UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

An analysis of the effect of the rotational, convex, poly-axial, mechanical knee brace (prototype I).. Cooke, Christopher 1977

You don't seem to have a PDF reader installed, try download the pdf

Item Metadata

Download

Media
[if-you-see-this-DO-NOT-CLICK]
[if-you-see-this-DO-NOT-CLICK]
UBC_1977_A7_5 C66.pdf [ 17.47MB ]
Metadata
JSON: 1.0077338.json
JSON-LD: 1.0077338+ld.json
RDF/XML (Pretty): 1.0077338.xml
RDF/JSON: 1.0077338+rdf.json
Turtle: 1.0077338+rdf-turtle.txt
N-Triples: 1.0077338+rdf-ntriples.txt
Original Record: 1.0077338 +original-record.json
Full Text
1.0077338.txt
Citation
1.0077338.ris

Full Text

AN ANALYSIS OF THE EFFECT OF THE ROTATIONAL/ CONVEX/ POLY-AXIAL/ MECHANICAL KNEE BRACE (PROTOTYPE i) ON THE STABILITY AND DYNAMIC RANGE OF MOTION OF THE KNEE JOINT by  CHRISTOPHER COOKE B . A . / B . P . H . E . , Queen's U n i v e r s i t y , B . E d . , Queen's U n i v e r s i t y ,  1973  1974  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE  PJEQUIRENENTS FOR THE DEGREE OF MASTER OF PHYSICAL EDUCATION  in THE  SCHOOL OF PHYSICAL EDUCATION AND  We  RECREATION  a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t h e  required standard  THE  UNIVERSITY OF BRITISH COLUMBIA MARCH, 1977  (c^  C h r i s t c p h e r Cooke, 1 9 7 7  In p r e s e n t i n g t h i s t h e s i s in p a r t i a l f u l f i l m e n t o f the requirements f o r an advanced degree at the U n i v e r s i t y the L i b r a r y  of B r i t i s h Columbia, I agree that  s h a l l make i t f r e e l y a v a i l a b l e f o r  r e f e r e n c e and s t u d y .  I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying o f t h i s  thesis  f o r s c h o l a r l y purposes may be g r a n t e d by the Head of my Department or by h i s r e p r e s e n t a t i v e s .  It  i s understood that c o p y i n g or p u b l i c a t i o n  o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d without my written permission.  Department of  Graduate Studies, School of Physical Education and Recreation  The U n i v e r s i t y  o f B r i t i s h Columbia  2075 Wesbrook P l a c e V a n c o u v e r , Canada V6T 1W5  D a t e  6  March 23, 1977  ABSTRACT  The f u n c t i o n a l l o s s o f knee s t a b i l i t v t h a t r e s u l t s from s o f t  tissue  and ligamentous i n j u r y i s a s e r i o u s problem f o r the c o n p e t i t i v e athlete.  N o n - s u r g i c a l attempts t o r e s t o r e f e m o r o - t i b i a l  stability  and f u n c t i o n have been c e n t e r e d on t h e e x t e r n a l a p p l i c a t i o n o f s u p p o r t i v e tape and a t h l e t i c knee b r a c e s . a r e a v a i l a b l e on the market today.  Several a t h l e t i c braces  The more s u b s t a n t i a l ones,  however, have p r o v e n ajrtibersane and uncomfortable i n t h e i r  attempts  t o p r o v i d e s u p p o r t f o r the u n s t a b l e knee. P r o t o t y p e I o f tlie r o t a t i o n a l , convex, p o l y - a x i a l , m e c h a n i c a l knee b r a c e  ( T a y l o r Brace) was  s u b j e c t e d t o t e s t i n g t o deteririine  i t s e f f e c t on knee s t a b i l i t y and dynamic range o f m o t i o n . E l e c t r o g o n i o m e t r i c r e c o r d i n g s o f knee f u n c t i o n i n t h r e e m u t u a l l y p e r p e n d i c u l a r movement parameters were o b t a i n e d from each s u b j e c t a t v a r y i n g speeds o f ambulation.  T e s t i n g was  conducted i n the  l a b o r a t o r y f o r unbraced and b r a c e d c o n d i t i o n s u s i n g a 2 x 2 c o l l a p s i b l e parallelogram chain electrogoniometer. I n s t a n t c e n t e r o f r o t a t i o n pathways and j o i n t s u r f a c e v e l o c i t y a n g l e s were determined from roentgenogram  a n a l y s i s o f the u n s t a b l e  knee f o r unbraced and b r a c e d c o n d i t i o n s .  Seven m e d i a l  roentgenograms  were taken o f the knee w i t h t h e femur f i x e d and the t i b i a moved from n i n e t y degrees o f f l e x i o n t o z e r o degrees o f f l e x i o n i n  increments o f f i f t e e n t o twenty d e g r e e s . S t r e s s a n a l y s i s was  c a r r i e d o u t on the u n s t a b l e knee u s i n g  m e c h a n i c a l s t r e s s machine. j o i n t and  R e g u l a t e d f o r c e s were a n p l i e d t o the knee  r a d i o g r a p h i c changes i n the range o f m e d i a l and  l a x i t y recorded e v a l u a t i o n was  f o r the unbraced and b r a c e d knee.  anterior  Subjective  a l s o conducted i n which s u b j e c t s e v a l u a t e d  the  T a y l o r Brace v e r b a l l y , a f t e r each s e s s i o n o f a c t i v i t y , and o v e r a l l w r i t t e n assessement a t the end o f the s t u d y . o f brace c o n s t r u c t i o n and  a  i n an  Various  aspects  f u n c t i o n were d i s c u s s e d under p r e - d e t e r m i n e d  criteria. Electrogoniometric general  r e s u l t s showed t h a t the T a y l o r Brace had  a  r e s t r a i n i n g e f f e c t on unwanted i n t e r n a l - e x t e r n a l r o t a t i o n  and v a r u s - v a l g u s  movement o f the knee.  Reductions i n the  range were a l s o r e c o r d e d b u t were c o n s i d e r e d t o t o t a l knee f u n c t i o n .  T h e r e was  flexion-extens  unimportant as a h i n d r a n c e  a l s o an i n d i c a t i o n t h a t  the  c o n t r a - l a t e r a l , unbraced knee p a t t e r n changed f o l l o w i n g b r a c i n g . There were no c o n s i s t e n t t r e n d s  i n the p a t t e r n o r d i s o e r s i o n  o f the i n s t a n t c e n t e r o f r o t a t i o n pathways f o l l o w i n g b r a c i n g . c o n s i s t e n t s h i f t i n g p o s t e r i o r l y and c e n t e r s and however, was  s u p e r i o r l y o f the i n d i v i d u a l  a change i n abnormal j o i n t s u r f a c e v e l o c i t y a n g l e s , n o t e d f o l l o w i n g a p p l i c a t i o n o f the T a y l o r B r a c e .  S u b j e c t i v e e v a l u a t i o n suggested s e v e r a l minor a s p e c t s c o n s t r u c t i o n f o r improvement i n f u t u r e p r o t o t y p e s . rigidity,  A  Triigh c u f f  t i b i a l a b r a i s o n and b r a c e s l i p p a g e were c i t e d as  f o r improvement.  Knee j o i n t range and  o f brace  a r t i c u l a t i o n was  areas  considered  excellent as well as ease of a p p l i c a t i o n , o v e r a l l brace comfort, lightness and cosmetics of design.  ACKNOWLEDGEMENTS Had  i t n o t been f o r t h e e x o n e r a t i o n o f Mr. George T a y l o r  (G.F. S t r o n g R e h a b i l i t a t i o n Center) t h i s study c o u l d not have place. brace  H i s i n i t i a l kindness  taken  i n a l l o w i n g the f i r s t p r o t o t y p e s o f h i s  t o be t e s t e d and h i s subsequent h e l p and a d v i c e t h r o u g h o u t have  made t h i s study p o s s i b l e . Thanks a r e due  t o Dr. Robert Hindmarch, Ms.  Sue  F i f e , Dr.  Ted  Rhodes and Dr. D a v i d Harder f o r t h e i r c r i t i c i s m s and a d v i c e  during  tlie s t u d y .  Bridge  Thanks are a l s o due  t o Dr. Frank Cox  (Workers' Compensation Board) f o r t h e i r a d v i c e on technique; for  t o Ms.  roentgenogtam  L e f k i K r i p t o s (G.F. S t r o n g R e h a b i l i t a t i o n Center)  her h e l p w i t h roentgenogram a n a l y s i s ; t o Mr.  (Canadian  and Dr. T.  Steve  Cousins  A r t n r i t i s and Rheumatism S o c i e t y ) f o r h i s k i n d h e l p  and  a d v i c e d u r i n g e l e c t r o g o n i o m e t r i c t e s t i n g ; and t o t h e s u b j e c t s , Bruce Goldsmid, B r i a n B a r k e r and Doug F i n l a y f o r t h e i r time cooperation.  My  and  thanks.  F i n a l l y , a s p e c i a l n o t e o f thanks t o D a v i d Rankine and F i e l d f o r t h e i r e x c e l l e n t a r t work, and o f c o u r s e t o  L.C.  Bob  vi  TABLE OF CONTENTS  Page LIST OF TABLES  i x  LIST OF FIGURES  x  Chapter I  STATEMENT OF THE PROBLEM  1  Introduction  1  Nature and Scone o f the Problem  2  Knee Brace D e s c r i p t i o n  5  Statement o f the Problem  9  J u s t i f i c a t i o n and S i g n i f i c a n c e  II  of tlie Study  10  Delimitations  10  Assumptions and L i m i t a t i o n s  11  D e f i n i t i o n o f Terms  11  REVTE.'/ OF THE LITERATURE  15  Electrogoniometric Studies  15  Recent Electrogoniometric Evaluation o f J o i n t Motion  18  Electrogoniometry of Abnormal Knee Patterns  18  Functional Evaluation of Below-Knee  III  Braces  19  Bracing the Unstable Knee  21  Instant Center o f Rotation Theory . . . .  22  Summary  25  METHODS AND PROCEDURES Subjects  . .  27 27  vii  Chapter  Page Apparatus and Instrumentation  27  Experimental Procedure  29  Subjective Evaluation  29  Test C r i t e r i a  30  Electrogoniometric Measurement  31  Instant Center o f Rotation Measurement  37  Instant Center o f Rotation  IV  V  VI  Calculation  38  Stress A n a l y s i s  41  Anterior Laxity  42  Medial L a x i t y  43  L a x i t y Measurement Technique  45  RESULTS AND DISCUSSION  48  Electrogoniometer  48  Discussion  76  Instant Center o f Rotation  79  Discussion  85  Stress A n a l y s i s  87  Discussion  89  Subjective Evaluation  90  Discussion  92  SUMMARY AND CONCLUSIONS  94  Summar/  94  Conclusions  97  RECENT DEVELOPMENTS AND SUGGESTIONS FOR FURTHER RESEARCH  BIBLIOGRAPHY  98  New Prototypes  98  Suggestions f o r Further Research . . . .  103  -  104  viii  Chapter  Page  APPENDICES APPENDIX A - Knee Axes of Rotation  107 ....  108  APPENDIX 8 - Subject Case Histories . . . .  110  APPENDIX C - 2 x 2 Collapsible Parallelogram Chain Electrogonicmeter  113  APPENDIX D - Electrogoniometric Testing Data Sheet  115  APPENDIX E - Instant Center of Rotation Calculation  119  ix  L I S T OF  TABLES  Table 1  Page Average values of knee motion during slow, l e v e l walking f o r Subject A w i t h normal (stable) knees  49  Average values of knee motion during slow, l e v e l running f o r Subject A w i t h normal (stable) knees  49  Average values of knee motion during slow, l e v e l walking f o r Subject B w i t h abnormal (unstable) knee  56  Average values o f knee motion during slow, l e v e l running f o r Subject B w i t h abnormal (unstable) knee  56  Average values o f knee motion during slow, l e v e l walking f o r Subject C w i t h abnormal (unstable) knee  63  Average values of knee motion during slow, l e v e l running f o r Subject C w i t h abnormal (unstable) knee  63  Average values o f knee motion during slow, l e v e l walking f o r Subject D w i t h abnormal (unstable) knee  70  Average values of knee motion during slew, l e v e l running f o r Subject D w i t h abnormal (unstable) knee  70  9  J o i n t surface v e l o c i t y angles f o r Subject B, unstable knee, unbraced and braced  81  10  J o i n t : surface v e l o c i t y angles f o r Subject C, unstable knee, unbraced and braced  83  11  Medial l a x i t y values  87  12  A n t e r i o r l a x i t y values  88  13  A n t e r i o r l a x i t y reduction values  88  2  3  4  5  6  7  8  X  L I S T OF FIGURES  Figure  "age  1  L e n n o x - l l i l l De-rotation Brace  3  2  Taylor Brace, l a t e r a l view  5  3  Taylor Brace j o i n t , exploded view . . . .  6  4  P o s t e r i o r view o f the knee w i t h the Taylor Brace a p p l i e d  7  5  L a t e r a l roentgenogram o f the knee w i t h the Taylor Brace a p p l i e d  8  5  Sequence view o f knee w i t h Taylor Brace applied  9  7  Comparison views o f o f f s e t and i n - l i n e hinge j o i n t s  13  8  Instant center l o c a t i o n w i t h r e l a t i v e p o s i t i o n s o f the t i b i a and femur . . . .  24  9  Electrogoniometer a n p l i c a t i o n shaving the c o l l a p s i b l e parallelogram chain and potentiometer c l u s t e r  31  Proper parallelogram chain p o s i t i o n a t 45 e x t e r n a l r o t a t i o n  32  Electrogoniometer a p p l i c a t i o n t o the unbraced knee  33  Experimental set-up shaving segment o f hallway used and equipment f o r electrogoniometer t e s t i n g  35  13  Exoerimental apparatus f o r braced electrogoniometer t e s t i n g  36  14  Subject p o s i t i o n i n g f o r i n s t a n t center o f r o t a t i o n x-ray a n a l y s i s  37  10 11 12  xi  Figure 15  16  17  18  19  Page Centrode l o c a t i o n from the movement o f two p o i n t s Instant center of rotation  translation  frcm 90  of flexion  of flexion  t o 10  39  .  41  M e c h a n i c a l s t r e s s apparatus p o s i t i o n e d f o r a n t e r i o r l a x i t y measurement, j o i n t unstressed  42  Knee p o s i t i o n f o r m e d i a l measurement  44  Experimental measurement  laxity  set-ur) f o r m e d i a l  laxity 45  20  A n t e r i o r l a x i t y measuring t e c h n i q u e  21  Medial  22-A  Electrogoniometric t r a c i n g s o f Subject A w i t h normal knees d u r i n g unbraced, slow, l e v e l walking  50  Electrogoniometric t r a c i n g s of Subject w i t h normal knees d u r i n a slow, l e v e l w a l k i n g w i t h the T a y l o r Brace on t h e r i g h t knee  51  22- B  23- A  23- B  24- A  24-B  l a x i t y measuring t e c h n i q u e  .  .  . . .  46 47  A  Electrogoniometric t r a c i n g s of Subject A w i t h normal knees d u r i n g unbraced, slow, l e v e l running  52  Electrogoniometric t r a c i n g s of Subject w i t h normal knees d u r i n g slow, l e v e l r u n n i n g w i t h the T a y l o r B r a c e on t h e r i g h t knee  53  A  Electrogoniometric tracings of Subject 3 w i t h abnormal knee d u r i n g unbraced, slow, l e v e l walking  57  Electrogoniometric tracings of Subject w i t h abnormal knee d u r i n g slow, l e v e l w a l k i n g w i t h the T a y l o r Brace on t h e l e f t knee  58  B  xii  Figure 25-A  25- B  26- A  26-B  27- A  27- B  28- A  28- B  Page Electrogoniometric t r a c i n g s o f Subject B w i t h abnormal knee during unbraced, slow, l e v e l running  59  Electrogoniometric t r a c i n g s o f Subject B w i t h abnormal knee during slow, l e v e l running w i t h the Taylor Brace on the l e f t knee  60  Ele(_±rc>goniaTietric t r a c i n g s o f Subject C w i t h abnormal knee during unbraced, slow, l e v e l walking  64  E l e c t r o g o n i a n e t r i c t r a c i n g s o f Subject C w i t h abnormal knee during slow, l e v e l walking w i t h the Taylor Brace on the r i g h t knee  65  Electrogoniometric t r a c i n g s o f Subject C w i t h abnormal knee during unbraced, slow, l e v e l running  66  Electrogoniometric t r a c i n g s o f Subject C w i t h abnormal knee during slow, l e v e l running w i t h the Taylor Brace on tlie r i g h t Isnee  67  Electrogoniometric t r a c i n g s o f Subject D w i t h abnormal knee during unbraced, slow, l e v e l walking  71  Electrogoniometric t r a c i n g s o f Subject D with abnormal knee during slow, l e v e l walking w i t h the L e n n o x - H i l l D e - r o t a t i o n a l 3race on the r i g h t knee  72  Electrcgoniometric t r a c i n g s o f Subject D w i t h abnormal knee during unbraced, slow, l e v e l running  73  Elec±rwoniometric t r a c i n g s o f Subject D w i t a abnormal knee during Slav, l e v e l running w i t h the Lennox-Hill De-rotational Brace on the r i g h t knee  74  :  29- A  29-B  xiii  Figure 30  Page Pathway o f i n s t a n t c e n t e r o f r o t a t i o n w i t h r e s p e c t t o t h e t i b i a and femur f o r S u b j e c t B, l e f t knee, u n s t a b l e . . . .  80  Pathway o f i n s t a n t c e n t e r o f r o t a t i o n w i t h r e s p e c t t o the t i b i a and femur f o r S u b j e c t C, r i g h t knee, u n s t a b l e . . .  82  32  Prototype  I, T a y l o r B r a c e  93  33  Prototype  I I , T a y l o r Brace  99  34  Prototype  I I I , T a y l o r Brace  100  35  Prototype  I I I , l a t e r a l view showina t h i g h  31  and c a l f c u f f s w i t h webbing removed  . . .  101  36  Joint fixation  102  37  Parallelogram chain linkages  113  38  Instant.center of r o t a t i o n c a l c u l a t i o n  . .  119  CHAPTER I STATEMENT OF THE PROBLEM  Introduction  During normal a c t i v i t y , t h e ligaments o f the knee j o i n t a r e e s s e n t i a l f o r the c o n t r o l , i n t e g r i t y and s t a b i l i t y o f the knee. The s p e c i f i c f u n c t i o n o f the i n d i v i d u a l ligaments (Wolf,  1973)  and t h e f u n c t i o n a l l o s s t h a t r e s u l t s from s o f t t i s s u e and ligamentous i n j u r / , s i n g l y o r i n combination, has been w e l l documented (Kennedy, Hughston e t a l ,  1971;1973; O'Donoghue, 1973; Slocum, 1974;  1976; and E r i k s s o n , 1976).  as a r e s u l t o f p a r t i a l o r complete structures  I n t e r n a l derangement,  l e s i o n s o f the  ligamentous  o f the knee has been c l i n i c a l l y shown t o produce  exaggerated m e d i a l and a n t e r i o r l a x i t y and i n s t a b i l i t y o f the knee j o i n t w i t h r e s u l t a n t p a i n and l o s s o f f m o t i o n  (Kennedy and Fowler,  1971). Attempts  to restore  f e m o r o - t i b i a l s t a b i l i t y by t h e a p p l i c a t i o n  o f e x t e r n a l s u p p o r t have been approached  from two d i r e c t i o n s .  Researchers i n t e r e s t e d i n the n o n - s u r g i c a l  t r e a t m e n t o f the  athlete  2  who wishes t o r e t u r n t o a t h l e t i c c c n p e t i t i o n , have s t u d i e d t h e e f f e c t s o f t a p i n g on the u n s t a b l e knee  (Roser, M i l l e r and Clawson,  1971; Noonan and Cooke, 1976).  B i a n e c h a n i c a l and m e d i c a l r e s e a r c h e r s  (Lehmann, Warren and DeLateur,  1970; Poser, M i l l e r and Clawson, 1971;  Kennedy and F a b l e r , 1974) have been concerned w i t h t h e e f f e c t o f b r a c i n g on knee s t a b i l i t y , motion and a t h l e t i c  function.  Nature and Scope o f t h e Problem  S e v e r a l a t h l e t i c knee b r a c e s a r e a v a i l a b l e on the  Lennox-Hill Derotation Brace  1  tlie market today,  b e i n g one t h a t has been shown, w i t h  p r o p e r a p p l i c a t i o n , t o reduce c h r o n i c knee i n s t a b i l i t y , p a i n and s w e l l i n g i n damaged knees (Kennedy, 1974). for  Although s u p p o r t i v e  the c o r r e c t i o n o f m e d i o - l a t e r a l and a n t e r o - p o s t e r i o r movement,  tlie n a t u r e o f the a p p l i c a t i o n o f the L e n n o x - H i l l B r a c e , however, has tended t o s a c r i f i c e comfort, l i g h t n e s s and f l e x i b i l i t y f o r s t r e n g t h and s u p p o r t . O f t e n o b s t r u c t i v e on q u a d r i c e p s and h a m s t r i n g b u l k , and i r r i t a t i n g through t h e p o p l i t e a l r e g i o n o f the knee w i t h a c t i v e use, tae  L e n n o x - H i l l B r a c e has p r o v e n curiaersome and u n c o m f o r t a b l e .  Information available on request from Hodgson Orthotics Ltd., 1650 West Broadway, Vancouver, B.C. V6J 1X6.  The s t r a p s f o r t h e b r a c e attachment t o t h e t h i g h and c a l f ,  tlie  b i - l a t e r a l d e r o t a t i o n s t r a p s and t h e metal frame o f t h e b r a c e  itself  are c o n s t r i c t i v e and can reduce c i r c u l a t i o n t o t h e u n d e r l y i n g tissues  ( F i g u r e 1).  F i g u r e 1. L e n n o x - H i l l D e r o t a t i o n B r a c e shewing (A) and (C) s t r a p s f o r b r a c e attachment t o t h e t h i g h and c a l f ; (E) b i - l a t e r a l d e r o t a t i o n s t r a o s and (D) m e t a l b r a c e frame.  To t h e a t h l e t e , o b s t r u c t i o n o f muscle  f u n c t i o n and numbness o f tlie  limb as a r e s u l t o f c o n s t r i c t i o n o f s u r f a c e v e s s e l s , and t h e i r r i t a t i o n on tlie s k i n can s e r i o u s l y hamper t h e d u r a t i o n o f use and tlie e f f i c i e n c y o f w a l k i n g o r running.  The movement  mechanics  of the Lennox-Hill, "Bub" DuribiLknit^ and PaLmer Athletic Braces J  have been built into bi-lateral supportive struts i n the form of single hinge and off-set hinge joints (See Figure 1 , Definition of Terms). Allowing planar movement i n the fixed, single-axis direction of flexion and extension, conventional athletic brace joint designs have ignored the internal-external rotation and varus-valgus movement of the tibia and femur that takes place during normal knee motion. Jesswein (1966) developed a polycentric knee joint that provided stability, at the same time allowing for a shifting of the knee brace axis with the angulation of the anatomical joint.  Its one drawback  for functional use was that i t only allowed flexion with weight-bearing up to fifteen degrees.  To date, no mention has been found i n the  literature of a device flexible enough i n i t s design to simulate the anatomical functioning of the human knee joint, that i s not restricting because of i t s weight, that i s ccmfortable and that can provide the necessary knee stability, support and dynamic function.  'Manufactured by John B. Flaherty Co., Incorporated, New York, N.Y. Distributed by Sparlings Sporting Goods, 929 Granville St., Vancouver, B. 'Developed by Rex 8 . Palirer, M.D. of Seattle. Incorporated, Moberly, Missouri, U.S.A.  Available from Ouik-Cold  5  Knee Brace Description  The rotational, convex, poly-axial, mechanical knee brace (Taylor Brace) prototype consists of a lateral leg iron composed of two independently articulating metal extensions held together at the knee by a common, convex base (Figure 2). The leg iron i s constructed of .072 inch tempered, high carbon (C1095)' steel.  Figure 2.  Taylor Brace, lateral view.  Articulation simulating an anatomical knee movement comes about by the geometric slotting on the joint ends of the extension arms  6 moving s i m u l t a n e o u s l y  on t h e convex s u r f a c e o f the base.  The  pathway o f the e x t e n s i o n movement i s governed by p i n s s l i d i n g i n tne slots.  The n a t u r e o f the convex s u r f a c e o f fahe base and t h e s l o p e o f  the s l o t s on t h e e x t e n s i o n arms, a l l o w s r o t a t i o n o f the e x t e n s i o n s t o the i n s i d e and t o t h e o u t s i d e  (Figure 3 ) .  7 The l a t e r a l l e g iron i s secured to the l e g by means of f l e x i b l e , moulded thigh and c a l f c u f f s .  These cuffs are made o f  polyester r e s i n , vacu-moulded from a p o s i t i v e cast of the l e g .  The  moulded thigh and c a l f cuffs are l i n e d with a foam padding to protect the skin i n the area o f application.  The a r t i c u l a t i n g j o i n t l i e s  close t o the skin at the knee but i s never i n contact  (Figure 4).  Figure 4. Posterior view o f the knee with the Taylor Brace applied. Note the p o s i t i o n o f the brace j o i n t r e l a t i v e to the feiroro-tibial a r t i c u l a t i n g surfaces. The arrow shows the location o f the a r t i c u l a t i n g j o i n t close to the s k i n .  F i g u r e 5. L a t e r a l view o f T a y l o r Brace a p p l i e d . Note the l o c a t i o n o f the b r a c e j o i n t and the p o s i t i o n o f the e x t e n s i o n arms r e l a t i v e t o t h e s h a f t s o f the femur and t i b i a .  A d d i t i o n a l m e d i a l s u p p o r t i s p r o v i d e d by an e l a s t i c s t r a p webbing e x t e n d i n g from the l a t e r a l l e g i r o n , o v e r the p a t e l l a , t i e medial aspect  o f t h e knee and a t t a c h i n g t o t h e f i b e r g l a s s  The p o p l i t e a l r e g i o n o f the knee i s , t h e r e f o r e , n o t r e s t r i c t e d (Figure 6 ) .  across cuffs.  9  Figure 6 . Sequence view of Taylor Brace applied showing (a) l a t e r a l view, (b) anterior view witn medial support strap o r i g i n a t i n g from l a t e r a l leg i r o n and crossing p a t e l l a , (c) medial view and (d) posterior view shaving free p o p l i t e a l region.  Statement of the Problem  The purpose o f t h i s study i s t o determine the e f f e c t of the r o t a t i o n a l , convex, poly-axial, mechanical knee brace (Taylor Brace) prototype on the s t a b i l i t y and dynamic range of motion of the human knee j o i n t .  10 J u s t i f i c a t i o n and S i g n i f i c a n c e o f the Study  The study i s d e s i g n e d t o a p p l y t h e p r e s e n t work b e i n g done i n the f i e l d of orthotic bracing to a t h l e t i c s .  In o a r t i c u l a r , i t i s b e i n g  done t o e v a l u a t e t h e T a y l o r Brace under f a i r l y n a t u r a l c o n d i t i o n s o f w a l k i n g and r u n n i n g .  I t i s a l s o i n t e n d e d t o u t i l i z e new  developments  i n the f i e l d o f e l e c t r o g o n i o m e t r y t o a n a l y s e normal and p a t h o l o g i c a l knee f u n c t i o n by d e t e r m i n i n g p a t h o l o g i c a l p a t t e r n s i n u n s t a b l e knees and s p e c i f i c a l l y o f tne e f f e c t o f b r a c i n g on knee f u n c t i o n . The use o f a roentgenogram  tedinique  f o r the d e t e r m i n a t i o n o f the  i n s t a n t c e n t e r o f r o t a t i o n f o r the knee i s a l s o b e i n g i n v e s t i g a t e d and tne T a y l o r Brace pattern.  i s b e i n g used t o e v a l u a t e the e f f e c t o f b r a c i n g on t h a t  S t r e s s a n a l y s i s o f j o i n t l a x i t y w i l l be i n c l u d e d t o determine  the e f f e c t o f the b r a c e on s t a b i l i t y o f the knee under f o r c e a p p l i c a t i o n . E l e c t r o g o n i o m e t r i c and roentgenogram a n a l y s i s o f the f u n c t i o n o f t i e b r a c e d knee can p r o v i d e i n f o r m a t i o n u s e f u l t o t h e o r t h o p a e d i c  surgeon,  a t h l e t i c t r a i n e r and r e h a b i l i t a t i o n t h e r a p i s t on the e f f e c t o f t h e T a y l o r Brace d e s i g n on the f u n c t i o n o f the abnormal knee.  Delimitations  The  d e t e r m i n a t i o n o f normal and p a t h o l o g i c a l knee f u n c t i o n w i l l  be  c o n f i n e d t o the e v a l u a t i o n o f dynamic c l i n i c a l e l e c t r o g o n i o m e t r i c d a t a o f the knee j o i n t .  A l l f u n c t i o n s o f w a l k i n g and r u n n i n g a r e performed  i n t h e l a b o r a t o r y under c o n t r o l l e d c o n d i t i o n s .  Tne  recorded data  can,  11 t h e r e f o r e , o n l y be i n t e r p r e t e d from t h i s r e s t r i c t e d s i t u a t i o n .  The  roentgenogram measurements f o r i n s t a n t c e n t e r o f r o t a t i o n c a l c u l a t i o n were performed i n a l y i n g p o s i t i o n from n i n e t y degrees o f f l e x i o n t o f u l l extension.  Tlie n o n - w e i g h t - b e a r i n g n a t u r e o f the  cannot, t h e r e f o r e , be c o r r e l a t e d w i t h the with weight-bearing.  f u n c t i o n o f the knee  Roentgenogram s t r e s s a n a l y s i s was  the l a b o r a t o r y u s i n g m e c h a n i c a l l y joint.  evaluation  Tlie r e s u l t s can o n l y be  simulated  considered  joint  c a r r i e d out i n  f o r c e s imposed a t the knee from t i i s  restricted  situation.  Assumptions and  Limitations  I n t h e a n a l y s i s o f e l e c t r o g o n i o m e t r i c d a t a , the f o l l o w i n g i n f o r m a t i o n is  taken i n t o c o n s i d e r a t i o n : (a)  e l g o n accuracy as determined by j o i n t s i m u l a t i o n r e p r o d u c t i o n w i l l keep the r e c o r d i n g o f the d a t a from knee f u n c t i o n t o w i t h i n an e r r o r o f f o u r p e r c e n t (Cousins, 1975:74).  In determining  t h e i n s t a n t c e n t e r o f r o t a t i o n f o r the knee,  f o l l o w i n g p o i n t s w i l l be (a)  (b)  the  followed:  two f i x e d p o i n t s on the femur are s u f f i c i e n t ( F r a n k e l and B u r s t e i n ,  considered  1971:916).  a l l m e d i o - l a t e r a l and a x i a l r o t a t i o n movement o f the knee i s i g n o r e d and o n l y f l e x i o n and e x t e n s i o n w i l l be used.  D e f i n i t i o n o f Terms  D e f i n i t i o n o f the f o l l o w i n g terms i s n e c e s s a r y f o r the  understanding  12 o f j o i n t f u n c t i o n and movement parameters  (See Appendix A: Knee Axes  of Rotation). Flexion-extension Movement about the knee j o i n t i n tlie s a g g i t a l p l a n e . Internal-external Rotation Inward and outward movement o f tlie t i b i a about i t s l o n g a x i s w i t h r e s p e c t t o t h e femur. Varus-valgus .Movement about the knee j o i n t o c c u r r i n g i n tlie c o r o n a l p l a n e . I n t e r n a l Derangement o f the Knee An a n a t o m i c a l d i s t u r b a n c e o f the s t r u c t u r e s w i t h i n the knee  joint,  b o t h bony and s o f t t i s s u e , r e s u l t i n g i n changes i n t h e mechanics o f the joint. Medial Laxity The e x t e n t o f the i n t r a - a r t i c u l a r  gap o r d i s t a n c e between the most  d i s t a l p o r t i o n s o f the s u b - d i o n d r a l bone o f the m e d i a l f e m o r a l  condyle  and the most d i s t a l l y p l a c e d p o r t i o n s o f the s u b - c h o n d r a l bone o f the medial t i b i a l  condyle.  I n damaged knees, m e d i a l l a x i t y i n c r e a s e s w i t h  s t r e s s a p p l i c a t i o n as a r e s u l t o f ligamentous  instability.  Anterior Laxity The tibial  amount o f f o r w a r d d i s p l a c e m e n t o f the m e d i a l and  lateral  c o n d y l e s w i t h r e s p e c t t o t h e m e d i a l and l a t e r a l f e m o r a l c o n d y l e s .  A n t e r i o r l a x i t y i n c r e a s e s w i t h s t r e s s a p p l i c a t i o n as a r e s u l t ligamentous  instability.  of  13  Offset Hinge J o i n t A j o i n t formed from, two extensions of metal c a r i n g together i n a corrmon hinge, a l l o w i n g independent a r t i c u l a t i o n of the extensions i n a f i x e d , s i n g l e - a x i s d i r e c t i o n through ninety degrees.  Tne hinge i s o f f s e t  p o s t e r i o r l y from the l i n e formed by the metal extensions (Figure 7).  Figure 7: (a) Offset hinge j o i n t and (b) hinge j o i n t .  Iiinge J o i n t A j o i n t formed from two extensions of metal coming together i n a conTnon  hinge a l l o w i n g independent movemsnt of the extensions i n a  f i x e d , s i n g l e - a x i s d i r e c t i o n through ninety degrees.  The hinge o r  point o f a r t i c u l a t i o n i s i n l i n e w i t h the metal extensions (Figure 7) .  Poly-centric Joint A j o i n t formed through t h e geared a r t i c u l a t i o n o f two e x t e n s i o n s o f m e t a l about each o t h e r on a common p l a n e . a fixed-axis direction.  T h i s a l l o w s movement i n  The g e a r e d n a t u r e o f t h e j o i n t produces a  d r i v i n g a c t i o n w i t h t h e r e s u l t t h a t one m e t a l e x t e n s i o n i s d r i v e n about t h e o t h e r p r o d u c i n g two axes o f r o t a t i o n . Poly-axial A term used t o d e f i n e a r t i c u l a t i o n i n more than one p l a n e o r about more than one a x i s .  The human knee j o i n t i s p o l y - a x i a l i n t h a t t h e a x i s  o f r o t a t i o n i s c o n s t a n t l y s h i f t i n g o r t r a v e l l i n g d u r i n g a c t i v e knee function.  15  CHAPTER II REVIEW OF THE LITERATURE  Electrogoniometric Studies  Electrogoniornetry* measures motion using potentiometer transducers. There are recording techniques for measuring joint motion using closedcircuit video tape, strobasccpic cinematography and motion analysis, but the techniques themselves are time consuming and the data must be reduced to useable numerical or graphical information. The electrogoniometer is externally worn by the subject and converts joint movement into voltage.  The data produced i s easily interpreted i n direct graphical  form. Electrogoniometric evaluation of human joint motion has been divided into the research activities of the following three major groups: (1)  The investigations of Karpovich et a l (1960, 1962, 1964, 1965)  initiated the c l i n i c a l use of the elgon.  This device consisted of a  potentiometer and two metal bars or lever arms, one attached to the potentiometer casing and one attached to the potentiometer shaft.  * "electro" refers to the voltage produced by the potentiometer motion transducer; "goniometry" oomes from the Greek, gonia, which means angle and refers to angle movement. The device used i s called an electrogoniometer, often referred to as an "elgon".  16 One lever arm was strapped above the joint and one below.  By  aligning the shaft of the potentiometer to the joint axis of rotation, joint motion in that plane could be measured. .Angular joint rotation was converted to a voltage output by the potentiometer, which was then graphically recorded.  Flexion-extension of the knee and ankle joints  were measured for normal and pathological gaits during various, everyday and athletic activities.  The work of Karpovich et a l initiated  research into dynamic movement evaluation by providing an recording of joint motion.  instantaneous  This work was limited, however, because:  (a)  knee joint motion evaluation was limited to flexion-extension, ignoring the additional movement parameters of internal-external rotation and varus-valgus that take place coincident with the normal flexion-extension phase of knee articulation.  (b)  most of the published data was for one leg only; the movement of the unmonitored leg and i t s effect on gait pattern was not considered.  (c)  potentiometer alignment with the joint center of rotation was a matter of guesswork and could vary between successive applications to yield a significant source of error. The constantly shifting axis of the poly-axial anatomical knee joint could not be accurately accommodated by a fixed, single-axis mechanism.  (2)  Johnson and associates advanced the work of Karpovich,  evaluating the movement of the hip (Johnson, 1969) and knee joints (Kettlekamp and Johnson, 1970) during normal walking and of the knee during activities of daily living (Laubenthal and Kettlekamp, 1972). Johnson and Kettlekamp established the f i r s t electxogoniometric values for the three mutually perpendicular rotations of flexion-extension, varus-valgus and internal-external rotation of the knee.  Laubenthal  and Kettlekamp provided useful electrogoniometric data of knee function  during a c t i v i t i e s o f climbing s t a i r s , Although  lifting  o b j e c t s and s i t t i n g down.  t h e i r work c o n t r i b u t e d t o t h e knowledge o f j o i n t motion, tlie  s o l u t i o n s o f Johnson and h i s a s s o c i a t e s were a l s o r e s t r i c t e d because: (a)  t h e i r measuring d e v i c e was n o t s e l f - a l i g n i n g and had t o be p o s i t i o n e d f o r each t r i a l w i t h i n a g i v e n d i s t a n c e o f t h e calculated j o i n t center.  (3)  Lamoreux (1971), i n h i s s t u d i e s o f g a i t , s e t down t h e most  e x t e n s i v e c r i t e r i a f o r t h e e v a l u a t i o n o f human j o i n t motion. developed  and t e s t e d an e x o s k e l e t o n  device that  He  simultaneously  measured t h r e e d i m e n s i o n a l motion o f the p e l v i s and the major j o i n t s of  tlie r i g h t lower e x t r e m i t y o f a s i n g l e , normal s u b j e c t w a l k i n g  treadmill.  Measurements were made a t s i x d i f f e r e n t speeds.  on a  Results  were p r e s e n t e d i n g r a p h i c a l form t o p e r m i t v i s u a l i n t e r p r e t a t i o n o f t h e e f f e c t s o f v a r i a t i o n s i n speed on t h e p a t t e r n s o f motion. Lamoreux's e x o s k e l e t o n h a d s e l f - a l i g n i n g p a r a l l e l o g r a m l i n k a g e s t h a t made e v a l u a t i o n o f p o l y - a x i a l j o i n t s p o s s i b l e by t h e use o f s i n g l e - a x i s potentiometers. reducing re-alignment  Although  e n h a n c i n g r e p r o d u c i b i l i t y by  e r r o r , Lamoreux's d e v i c e had t h e f o l l o w i n g  liiriitations: (a)  t h e w e i g h t o f t h e d e v i c e (3.5 k i l o g r a m s ) made i t q u i t e cumbersome and d i d n o t a l l o w more mobile a c t i v i t y than normal w a l k i n g .  (b)  t h e h i p a n a l o g was n o t s e l f - a l i g n i n g , a g a i n i n t r o d u c i n g tlie e r r o r o f alignment f o r s u c c e s s i v e t r i a l s .  (c)  tlie c o m p l i c a t e d a p p l i c a t i o n o f two s e l f - a l i g n i n g p a r a l l e l o g r a m l i n k a g e s f o r e v a l u a t i o n o f ankle motion produced a b u l k y d e v i c e .  (d)  the e l a b o r a t e n a t u r e o f a p p l i c a t i o n l i m i t e d i t s use t o a laboratory.  18 Recent E l e c t r o g o n i o m e t r i c E v a l u a t i o n o f J o i n t Motion  Recent work by Cousins d e s i g n capable  (1975) has produced a p a r a l l e l o g r a m c h a i n  o f measuring, s i m u l t a n e o u s l y ,  h i p , knee and ankle  joints.  t r i - a x i a l movement o f  the  As each p a r a l l e l o g r a m s c i s s o r s "unwanted  t r a n s l a t i o n s are absorbed w h i l e  three mutually  pass through t h e c h a i n unchanged."  perpendicular rotations  T h i s a l l o w s the d e v i c e t o be  e s s e n t i a l l y s e l f - a l i g n i n g and e v a l u a t i o n o f f l e x i o n - e x t e n s i o n , i n t e r n a l e x t e r n a l r o t a t i o n and v a r u s - v a l g u s  movement can be c a r r i e d o u t .  r o t a t i o n a l movement p a s s i n g through t h e c h a i n i s r e g i s t e r e d by  The potentiometers  p o s i t i o n e d a l o n g t h e axes o f r o t a t i o n and a permanent g r a p h i c a l r e c o r d is  obtained. The  is light  d e v i c e has been developed f o r e a s y , b i - l a t e r a l a p p l i c a t i o n , (1.7  kilograms)  and n o n - r e s t r i c t i n g .  I t can be used f o r  i n d o o r o r o u t d o o r t e s t i n g a t v a r y i n g r a t e s o f ambulation. a p p l i c a t i o n o f the p a r a l l e l o g r a m c h a i n d e v i c e i s c u r r e n t l y  Clinical teing  i n v e s t i g a t e d f o r the e v a l u a t i o n o f normal and p a t h o l o g i c a l g a i t s . R e p r o d u c i b i l i t y o f the e l e c t r o g o n i o m e t e r  was  measured by p l a c i n g  i t on a normal s u b j e c t and o b t a i n i n g a g r a p h i c a l r e c o r d o f walking. This  The equipment was  tecnnique  was  repeated  u n t i l r e p r o d u c i b i l i t y was  Electrogonicmetry  Kettlekamp e t a l  level  t h e n removed, r e p l a c e d and t e s t e d a g a i n . a number o f times f o r v a r i o u s  subjects  achieved.  o f Abnormal Knee P a t t e r n s  (1970) p r e s e n t e d d a t a on abnormal knee p a t t e r n s  19  from t h e i r s t u d i e s o f knee motion i n normal g a i t . t r a c i n g s of a p a t i e n t with degenerative  Elec±rogonioiretric  genu varum showed g r e a t e r knee  e x t e n s i o n d u r i n g t h e s t a n c e phase than d u r i n g n e u t r a l s t a n c e .  They  a l s o p r o d u c e d d a t a from a p a t i e n t w i t h rheumatoid a r t h r i t i s w i t h a l o s s o f bone from the l a t e r a l t i b i a l p l a t e a u and i n c r e a s e d v a l g u s . E l e r t r o g o n i c m e t r i c p a t t e r n s o f the knee showed v e r y l i t t l e f l e x i o n - e x t e n s i o n . The  abduction-adduction  p a t t e r n s were g r o s s l y abnormal w i t h the swing  phase o f the l e g d u r i n g normal w a l k i n g b e i n g q u i t e reduced. Karpovich  and T i p t o n  (1965) i n t h e i r s t u d i e s o f knee and  ankle  movements i n p a t h o l o g i c g a i t s showed e l e c t r o g o n i c m e t r i c d a t a from p a t i e n t s r e c o v e r i n g from i n t e r n a l derangements o f the knee.  They shaved  r e c o r d i n g s from a p a t i e n t r e c o v e r i n g from an " i n d u s t r i a l a c c i d e n t " which r e s u l t e d i n i m p a i r e d e x t e n s i o n o f the r i g h t knee.  As a r e s u l t o f t h i s  i n j u r y , f l e x i o n d u r i n g tlie s u p p o r t phase o f w a l k i n g was p a t i e n t walked s t i f f - l e g g e d .  The  second s e t o f d a t a was  r e c o r d e d f o u r days a f t e r a r i g h t m e d i a l menisectcmy. walked w i t h a limp and  f l e x i o n i n t h e r i g h t knee was  nature o f t h e i n j u r i e s , u n f o r t u n a t e l y , was  and  the  from a p a t i e n t  The p a t i e n t l i m i t e d to fourteen  degrees as compared t o s i x t y degrees i n t h e l e f t knee.  was  absent  The  not a v a i l a b l e .  specific T h e i r study  l i m i t e d t o two s e t s o f t r a c i n g s .  F u n c t i o n a l E v a l u a t i o n o f Below-Knee i3races  P u b l i s h e d d a t a on the f u n c t i o n a l e v a l u a t i o n o f b r a o e d limbs i s n o t abundant i n the l i t e r a t u r e .  F o r t h e most p a r t , i t has been  20 confined to minor references in studies of joint motion. Electrogoniatietric evaluation of braced joint function began with the work of Karpovich and Tipton (1964). evaluation of the electrogoniometer,  In their study of the c l i n i c a l they included sane information  on the effect of wearing a below-knee, lower, l e f t leg brace on the joint movement of a cerebral palsied individual.  They found that a  marked reduction in flexion occurred in the l e f t knee range but l i t t l e change occurred in the right knee pattern.  Their observations were  limited to flexion-extension evaluation of an isolated individual. The other movement parameters of internal-external rotation and varus-valgus of the knee were not included and no data was available for joint function before bracing.  Information on the type of brace  used was not available. Rozin et a l (1972) correlated electrogoniometric results of nip motion with electromyography of the muscles of the lower limb.  A  standard below-knee, drop-foot brace was used consisting of tovo side bars attached through a pivot joint to a heel stirrup.  The  drop-foot  stop mechanism allowed ankle movement in the range of ten degrees of plantar flexion and free dorsi-flexion but eliminated the movements of abduction-adduction and inversion-eversion.  The analysis was limited  to normal subjects and the effect of bracing on pathological joint function was not considered.  Electrogoniometric evaluation consisted of motion  of the hip in the frontal and saggital planes and of knee flexion-extension during slow walking. Rozin et a l found that continuous knee flexion occurred on the braoed leg as well as:persistent contraction of the quadriceps muscle.  The mechanics of the brace used was below the knee and did not involve the knee joint.  They suggested that these changes i n the pattern of  gait may explain early fatigue and the possible development of secondary degenerative changes of the knee joint. Biomechanical evaluation of knee function was carried out by Lehman et a l (1970), who analyzed the forces affecting knee stability in normal subjects using short-leg, below-knee braces. Transducers were mounted just below the calf band or shell of the brace to monitor the force produced, i n pounds, between the leg and the brace during the various phases of normal gait.  Their study showed that many designs of  belav-knee braces can be used to prevent hyperextension of the knee in conditions of genu recurvatum and that knee stability can be inhanced by the use of toe levers from the f l a t foot to the toe-off stage of stance.  Bracing the Unstable Knee  Roser et a l (1971) have produced data concerning the effect of taping and bracing on medio-lateral and antero-posterior stability of the knee. Medial and lateral instability were measured in four male college athletes with c l i n i c a l l y unstable knees by applying varus and valgus stress to the knee while maintaining i t flexed to twenty degrees. A twenty pound force was applied to the ankle v i a a f e l t sling keeping the knee stable.  The knee was then flexed to ninety degrees and  anterior and posterior stress exerted by applying a twenty pound force  22  on t h e p r o x i m a l t i b i a . Roentgenogram e v a l u a t i o n was c a r r i e d o u t under t h e s e s t r e s s e d c o n d i t i o n s and d i s p l a c e m e n t o f t h e a r t i c u l a t i n g s u r f a c e s  calculated  f o r t a p e d and untaped and b r a c e d and unbraced s i t u a t i o n s u s i n g one and one h a l f i n c h a t h l e t i c t r a i n e r ' s tape and a Palmer Knee B r a c e . The  s t u d y shewed t h a t t h e o n l y s i g n i f i c a n t improvement i n s t a b i l i t y  occurred and  i n a n t e r o - p o s t e r i o r movement w i t h t h e combined use o f tape  a Palmer Knee B r a c e . Kennedy e t a l  t o apply  (1974) have made use o f a c l i n i c a l s t r e s s machine  f o r c e s t o t h e knee j o i n t .  Medial,  l a t e r a l and a n t e r i o r l a x i t y  were measured by s t r e s s roentgenogram a n a l y s i s and v a l u e s f o r p a t i e n t s w i t h c h r o n i c knee i n s t a b i l i t y . of the Lennox-Hill determined.  De-rotation  obtained  The e f f e c t o f t h e a p p l i c a t i o n  Knee B r a c e on knee j o i n t l a x i t y was  Kennedy e t a l showed t h a t n i n e o u t o f 32 p a t i e n t s who had  c h r o n i c i n s t a b i l i t y and who wore t h e L e n n o x - H i l l  Brace shaved marked  r e d u c t i o n i n a n t e r i o r d i s p l a c e m e n t o f t h e m e d i a l and l a t e r a l condyles.  Case s t u d i e s were c i t e d i n which d i s p l a c e m e n t o f t h e t i b i a l  c o n d y l e s was r e d u c e d from t e n m i l l i m e t e r s t o 0.5 m i l l i m e t e r s and  tibial  from 15.4 m i l l i m e t e r s m e d i a l l y  medially  t o one m i l l i m e t e r l a t e r a l l y a f t e r  a p p l i c a t i o n o f t h e L e n n o x - H i l l Brace i n two s u b j e c t s .  Instant Center o f Rotation  Frcm Rouleaux's Theory o f Machines  Theory  (1876) we f i n d t h a t " r e l a t i v e  motions o f p l a n e f i g u r e s i n a common p l a n e considered  (con-plane f i g u r e s ) may be  t o be a r o l l i n g motion and t h e motion o f any p o i n t s i n them  23 can be determined as soon as the centroids (or instantaneous centers of rotation) of the figures are known." This concept can be applied to a cylinder rolling on a plane or to two circles rolling on each other. If we consider the femur and t i b i a (a combination of cylinder and plane) to be rigid bodies undergoing angular motion i n one, common plane (flexion-extension), then the points along that rigid body move, except one, that point being the instant center of rotation or centroid for the instant being considered. In considering the movement of the femur and tibia, we assume that a l l other axial rotations of internal-external rotation and varus-valgus do not exist.  During articulation between  these two links, movement nay be considered to be sliding or rolling. If the femur moves on a fixed t i b i a , sliding occurrs when the femoral axis remains at a constant angle with the axis of the tibia; or rolling occurs as the femoral axis undergoes angular motion relative to the axis of the t i b i a .  Usual knee motion i n the saggital plane i s  considered to be a combination of both.  By locating the instant center,  i t i s possible to identify the type of motion at the articulating surface since an instant center on the surface indicates that there i s a rolling motion, while an instant center not on the surface indicates that there is sliding (Frankel and Burstein, 1971). Figure 8-A shews a particular instant center with the relative position of the t i b i a and femur. The direction of the velocity of the instant center can be obtained by drawing a line perpendicular to a line joining the instant center to a point on the condylar surface. I f tlie  velocity  l i n e a t the p o i n t o f c o n t a c t between t h e j o i n t s u r f a c e s i s  t a n g e n t i a l t o t h e s u r f a c e s , they w i l l be s l i d i n g on each o t h e r w i t h a relatively  f r e e and normal a c t i o n as t h e knee moves ( F i g u r e 8-B).  8-A  8-B  F i g u r e 8. I n s t a n t c e n t e r l o c a t i o n w i t h r e l a t i v e p o s i t i o n s o f t h e t i b i a and femur (8-A), and j o i n t v e l o c i t y l i n e t a n g e n t i a l t o t h e j o i n t s u r f a c e s (8-B).  Velocity l i n e s non-tangential t o the j o i n t surface i n d i c a t e abnormal f r i c t i o n and wear a t t h e p o i n t o f c o n t a c t as a r e s u l t o f some pa theme c h a n i c a l change i n t h e a r t i c u l a t i n g t h a t t h e motion w i l l tend t o s e p a r a t e producing  a cam-like  action.  surfaces.  T h i s means  o r compress t h e j o i n t s u r f a c e s ,  S l i d i n g w i l l n o t be t a k i n g p l a c e b u t t h e  f r i c t i o n a l and compressive f o r c e s a t t h e s u r f a c e w i l l be i n c r e a s e d .  25 The  l e a s t amount o f f r i c t i o n o c c u r s when t h e d i r e c t i o n o f t h e  j o i n t surface v e l o c i t y l i n e i s tangent t o the contact surface.  Vtfien  the l i n e j o i n i n g tlie i n s t a n t c e n t e r t o a p o i n t on t h e a r t i c u l a r surfaces a t t h e i r point o f contact i s perpendicular  ( n i n e t y degrees)  t o t h e a r t i c u l a r s u r f a c e s , then t h i s c o n d i t i o n t a k e s p l a c e .  Helfet  (1959, 1963) h a d r e l a t e d worn areas i n t h e t i b i o - f e m o r a l j o i n t t o areas o f j o i n t s u r f a c e i n c o n t a c t w i t h d i s p l a c e d m e n i s c i ,  fibrotic  f a t pads and t o abnormal p a t t e r n s as t h e r e s u l t o f d i s p l a c e d o r damaged The femoral not.  ligaments. t e c h n i q u e determines whether t h e s u r f a c e d i r e c t i o n o f t h e and t i b i a l a r t i c u l a t i n g s u r f a c e s produces e f f i c i e n t s l i d i n g o r  E x a m i n a t i o n o f t h e i n s t a n t c e n t e r o f r o t a t i o n pathway and t h e  i n s t a n t c e n t e r j o i n t v e l o c i t y angles may i n d i c a t e abnormal p a t t e r n s and abnormality  o f a r t i c u l a t i o n as a r e s u l t o f seme p a t h o m e c h a n i c a l change  i n the j o i n t .  Summary  A r e v i e w o f t h e a v a i l a b l e l i t e r a t u r e r e v e a l s t h a t a comprehensive s t u d y e v a l u a t i n g t h e dynamic e f f i c i e n c y and f u n c t i o n o f an a t h l e t i c knee b r a c e has n o t been found. electrogeniometric  I n i t i a l s t u d i e s o f b r a c e s i n v o l v e d the  e v a l u a t i o n o f n o n - a t h l e t i c , belaw-knee b r a c e s  designed f o r the c o r r e c t i o n o f foot deformity  associated with  clinical  conditions. Results  from e l e c t r o m y o g r a p h i c a l  and s t r e s s a n a l y s i s s t u d i e s shaved  26  r e s u l t s from normal s u b j e c t s o n l y .  E v a l u a t i o n o f a t h l e t i c knee  b r a c e s has been c o n f i n e d t o t h e a p p l i c a t i o n o f e x t e r n a l f o r o e s f o r the c a l c u l a t i o n o f j o i n t l a x i t y .  Recent advances i n the e l e c t r o g o n i o m e t r i c  r e c o r d i n g o f j o i n t motion i n t h r e e a x i a l r o t a t i o n parameters  appear  s u f f i c i e n t t o conduct an a n a l y s i s o f knee motion o f the i n t e r n a l l y deranged knee and o f the e f f e c t o f b r a c i n g on t h a t p a t t e r n .  27  CHAPTER  III  METHODS AND PROCEDURES  Subjects  Three male a t h l e t e s , ages twenty-four,  t w e n t y - f i v e and  y e a r s s e r v e d as t e s t s u b j e c t s f o r the s t u d y .  One  twenty-nine  o f the s u b j e c t s  (A)  had normal ( s t a b l e ) knees w i t h no p r e v i o u s h i s t o r y o f knee i n j u r y . Both o f the o t h e r s u b j e c t s  (B and C) had s u f f e r e d l e s i o n s o f tine  m e d i a l c o l l a t e r a l l i g a m e n t and the m e d i a l meniscus o f one r e s u l t of a t h l e t i c competition.  I n a d d i t i o n , one  o f the two  showed marked a n t e r o - p o s t e r i o r l a x i t y w i t h i n t e r n a l t i b i a l under e x a m i n a t i o n w i t h t h e a n t e r i o r drawer t e s t . t e s t produced an abnormal amount o f m e d i a l The  The  joint line  second t e s t s u b j e c t showed d e g e n e r a t i v e  l e g as  subjects  rotation  abduction  made.  stress  opening.  changes i n the  a r t i c u l a r s u r f a c e o f the femur on roentgenogram e x a m i n a t i o n . d i a g n o s i s o f o s t e o c h o n d r i t i s dessecans was  the  A  Both s u b j e c t s r e l a t e d  a h i s t o r y o f c h r o n i c p a i n , s w e l l i n g and l a c k o f f u n c t i o n o f the i n j u r e d knee j o i n t w i t h a c t i v e use  Apparatus and  (See Case H i s t o r i e s , Appendix B ) .  Instrumentation  Dynamic e v a l u a t i o n o f knee j o i n t motion r e q u i r e s i n s t r u m e n t a t i o n p r e c i s e enough t o d e t e c t and r e g i s t e r movement i n degrees.  Roentgenogram  a n a l y s i s o f i n s t a n t c e n t e r s o f r o t a t i o n o f the knee j o i n t and  stress  28 analysis require the use of sophisticated techniques and equipment. The following apparatus and instrumentation was available for this study: (a)  two 2 x 2 collapsible parallelogram chain electrogoniometers* (Appendix C) capable of measuring movement i n three planes.  (b)  a signal attenuator box to apply a voltage to the potentiometers and to reduce the signal from the electrogoniometer to a voltage recordable by the strip chart recorder.  (c)  an S.E. Laboratories ultra-violet strip chart recorder model 3006 for recording the knee joint movements i n graphical form. Flexion-extension, internal-external rotation and varus-valgus of both knees were simultaneously recorded using six separate channels. A deflection of one millimeter on the graphical print-out was calibrated to register five degrees of motion.  (d)  a Phillips Telestater remote control x-ray unit with x-omatic film and fluorscopic pre-positioning f a c i l i t y . This device was used for roentgenogram measurement of tlie knee joint in braced and unbraced conditions for instant center of rotation analysis.  (e)  a Picker model 6800 S x-ray unit with single phase f u l l wave rectification and Kodak x-omatic regular intensifying screens. This device was used for roentgenogram measurement during stress analysis.  (f)  a General Electric x-ray viewer model 11 FVl for use i n x-ray interpretation and evaluation.  (g)  a stress; application apparatus for applying foroes to the knee joint consisting of a hand rachet and supporting stand.  (h)  a Pacific Scientific cable tensiometer model 401-1C-2 with one-sixteenth inch steel cable to monitor the force generated during stress application.  permission for use of the 2 x 2 collapsible parallelogram chain electrogoniometers has been kindly given by Mr. Steven Cousins of the Canadian Arthritis and Rheumatism Society, Vancouver, British Columbia, Canada.  (i)  a n y l o n s l i n g f o r c o m f o r t a b l e attachment o f the s t e e l c a b l e t o the l e g f o r s t r e s s a n a l y s i s .  (j)  t h r e e p r o t o t y p e s o f the l a t e r a l i r o n , r o t a t i o n a l , c o n v e x , p o l y - a x i a l , m e c h a n i c a l knee b r a c e ( T a y l o r B r a c e ) . +  E x p e r i m e n t a l Procedure  The  T a y l o r Brace was  evaluated  under the  following test  conditions: (a)  subjective  (b)  electrogoniometric  (c)  i n s t a n t c e n t e r o f r o t a t i o n measurement  (d)  stress  Subjective  (i) The  arm  +  analysis  Brace a p p l i c a t i o n T a y l o r B r a c e was the  c o m f o r t a b l y a p p l i e d by the s u b j e c t i n  f o o t was  i n s e r t e d through the t h i g h and  the b r a c e p o s i t i o n e d on the  o f the b r a c e was  femur and  measurement  Evaluation  f o l l o w i n g manner: c u f f s and  evaluation  leg.  The  p o s i t i o n e d p a r a l l e l t o and  the d i s t a l e x t e n s i o n  proximal  calf  extension  approximating  arm o f the b r a c e was  the  positioned  the parallel  p e r m i s s i o n f o r use o f the l a t e r a l i r o n , r o t a t i o n a l , convex, p o l y - a x i a l , m e c l i a n i c a l knee b r a c e p r o t o t y p e s has been k i n d l y g i v e n by Mr. George T a y l o r , G.F. S t r a n g R e h a b i l i t a t i o n C e n t e r , Department o f O r t h o t i c s , Vancouver, B r i t i s h Columbia, Canada.  30 t o and  a p p r o x i m a t i n g the t i b i a  o f the m e c h a n i c a l j o i n t was above the head o f the  (See F i g u r e  The  f i b u l a i n a p o s i t i o n a t the c e n t e r o f the p a t e l l a (See F i g u r e  m e d i a l s u p p o r t s t r a p was  4,  7).  page  a p p l i e d from i t s attachment on  l a t e r a l l e g i r o n , o v e r the p a t e l l a , and s e c u r e d t o "D" t h i g h and c a l f c u f f s .  The  e l a s t i c t i b i a l s t r a p was  and s e c u r e d t o the t i b i a l c u f f . l i n i n g up  The  hooks on  then  f e m o r a l c u f f was  then t i g h t e n e d  and  s e c u r e d t o a "D"  the the  tightened  aligned  a f a s t e n e r on the m e d i a l a s p e c t o f the t h i g h .  t h i g h s t r a p was  center  located i n a p o s i t i o n s i x centimeters  w i t h the knee i n f u l l e x t e n s i o n The  5, page 8) .  The  r i n g on  by elastic  the  femoral c u f f .  (ii)  Test  Criteria  W i t h the T a y l o r Brace a p p l i e d , the s u b j e c t engaged i n a s e l e c t e d p h y s i c a l a c t i v i t y o f h i s own the s u b j e c t was  choosing.  A f t e r c o m p l e t i o n o f the  asked t o v e r b a l l y e v a l u a t e the b r a c e on the  activity,  following  points: (a)  comfort and f i t i r r i t a t i o n p o i n t s , p i n c h i n g , c o n s t r i c t i o n and b r a c e movement on l e g , s l i p p a g e .  (b)  joint  numbness,  function ease o f a r t i c u l a t i o n , range o f a r t i c u l a t i o n , r e s t r i c t i o n s t o movement.  (c)  weight, s i z e , ease o f a p p l i c a t i o n and  removal, c o s m e t i c s .  A t the c o m p l e t i o n o f the s t u d y , the s u b j e c t was written  assessement as an o v e r a l l e v a l u a t i o n  asked f o r a  o f the T a / l o r B r a c e .  filectrogcnicmetric I^asurement Electrogoniometer application (i)  unbraced  The proximal attachment of the electrogoniometer consisted of thigh cuff frame constructed of 0.40 centimeter steel wire.  The frame  was fixed to the thigh by means of a velcro strap which extended behind the leg and was fastened. Two brass brackets fastened the oroximal arm of the electroopruareter rigidly to the frame and allowed no movement (Figure 9).  Figure 9. Electrogonicmeter application showing the collapsible parallelogram chain and potentiometer cluster (arrows). Note the thigh and calf wire frames with the velcro attachments.  Attachment  o f t h e d i s t a l arm o f the e l e c t r o g o n i o m e t e r t o t h e c a l f  accomplished i n the same manner. c a l f muscles  A m e t a l w i r e frame was  was  a p p l i e d t o the  and s e c u r e d by a v e l c r o s t r a p a t the f r o n t o f the l e g .  d i s t a l arm o f the e l e c t r o g o n i o m e t e r was i n s i d e a h o l l o w b r a s s tube w h i c h was  The  allowed t o telescope f r e e l y  r i g i d l y attached t o the  frame.  The p o t e n t i o m e t e r c l u s t e r was p o s i t i o n e d a t a l e v e l b e s i d e t h e p a t e l l a w i t h t h e knee i n f u l l e x t e n s i o n .  P r o p e r alignment o f the  c o l l a p s i b l e p a r a l l e l o g r a m c h a i n o f the e l e c t r o g o n i o m e t e r from i t s f u l l extended p o s i t i o n was  a c h i e v e d by r o t a t i n g i t outward from the knee t o  an angle o f f o r t y - f i v e degrees  (Figure  10).  F i g u r e 10. Proper parallelogram chain p o s i t i o n (arrows) a t 45 e x t e r n a l r o t a t i o n . Note the w a i s t pack, u m b i l i c a l c o r d and p o t e n t i o m e t e r l e a d s .  Power f o r t h e p o t e n t i o m e t e r s was s u p p l i e d by a s t a n d a r d 110 v o l t , 60 c y c l e w a l l o u t l e t v i a independent l e a d s t o each e l e c t r o g o n i o n e t e r . V o l t a g e o u t p u t from t h e p o t e n t i o m e t e r s t r a v e l l e d t o t h e r e c o r d e r v i a an u m b i l i c a l c o r d a t t a c h e d t o a w a i s t pack.  (ii)  braced  The T a y l o r Brace was a p p l i e d t o t h e knee as p r e v i o u s l y described.  The e l e c t r o g o n i o m e t e r was a t t a c h e d t o t h e b r a c e by "U"-beam  s t r u t s o f aluminum b o l t e d t o t h e b r a c e e x t e n s i o n arms. attachment o f the e l g o n c o n s i s t e d o f  The p r o x i m a l  a h o l l o w b r a s s tube a t t a c h e d t o a  p l a s t i c "I"-beam and r i g i d l y f i x e d t o t h e aluminum s t r u t  ( F i g u r e 11).  F i g u r e 11. E l e c t r o g o n i o m e t e r a p p l i c a t i o n t o t h e b r a c e d knee. Arrow p o i n t s t o r i g i d "U"-beam aluminum s t r u t . Note the p o s i t i o n o f the p o t e n t i o m e t e r c l u s t e r r e l a t i v e t o the brace j o i n t .  34  The d i s t a l attachment o f the elgon was constructed i n the same manner.  The elgon arms were inserted i n s i d e the hollow brass tubes.  The proximal arm o f the elgon was r i g i d l y fixed to the brass tube by adhesive tape, while the d i s t a l arm was allowed to telescope freely inside the tube.  Potentiometer and parallelogram chain alignment were  the same as previously described f o r unbraced attachment.  Test Procedure Following application of the electrogoniometer, the subject walked about the laboratory t o become accustomed to the apparatus.  He then  stood i n h i s n a t u r a l standing p o s i t i o n (neutral stance) and the recording l i g h t beam channels of the s t r i p chart recorder were adjusted to the zero p o s i t i o n .  I t should be noted that the zero p o s i t i o n represents  the standing p o s i t i o n of the subject.  Records o f knee j o i n t motion  were then recorded as motion from the neutral stance p o s i t i o n .  Ml  tests were conducted i n the laboratory s e t t i n g i n a segment o f hallway forty meters long (Figure 12). The subject was instructed t o stand a t one end o f the hallway and the recorder beams were adjusted t o zero again.  Tne subject then  walked u n t i l ten steps were recorded, exclusive o f the f i r s t and l a s t steps of the walk.  He then repeated the walk.  Recordings were  obtained under t e s t conditions o f slow, l e v e l walking and slow, l e v e l running.  A f t e r a ten minute rest, the subject was asked t o apply the  Taylor Brace.  B  Figure 12. Experimental set-uo shewing segment of hallway used, (a) s i g n a l attenuator box and (bj u l t r a - v i o l e t l i g h t s t r i p chart recorder. The subject i s i n n e u t r a l stance with the brace and electjxigeniometer applied.  The elgon was then mounted and the procedure repeated.  The  pattern o f knee motion as represented by the u l t r a - v i o l e t l i g h t s t r i p chart recordings was determined from the beam d e f l e c t i o n .  S i x channels  were used to record, simultaneously, movements o f flexion-extension, internal-external rotation and varus-valgus f o r both knees under unbraced and braced t e s t conditions. A beam d e f l e c t i o n o f one millimeter on the pront-out represented f i v e degrees o f motion. The chart speed was s e t at f i v e millimeters per second.  An  electrogoniometric t e s t i n g data sheet was kept on the s t a t i s t i c s o f each t e s t (See Appendix D) .  F i g u r e 13.  Experimental set-up f o r braced t e s t i n g .  37 Instant  C e n t e r o f R o t a t i o n Measurement  Instant  c e n t e r o f r o t a t i o n measurement was  o f the P h i l l i p s T e l e s t a t e r  remote c o n t r o l x - r a y u n i t .  assumed a p o s i t i o n l y i n g on t h e The  t h i g h was  made p o s s i b l e  side with the  The  selected  by  the  use  subject  l e g underneath.  f i x e d t o the x-ray t a b l e by means o f a canvas c u f f  a t t a c h e d t o the  t a b l e edge.  Tension i n the  c u f f was  c o n t r o l l e d by  rachet tightening  d e v i c e mounted t o the x - r a y t a b l e by  bracket  14).  (Figure  a  a  sliding  F i g u r e 14. Subject p o s i t i o n for instant center o f r o t a t i o n x-ray a n a l y s i s , ^ote the canvas c u f f (s) and the s l i d i n g b r a c k e t (d) f o r c u f f a p p l i c a t i o n t o the t a b l e .  S u p e r i m p o s i t i o n o f t h e m e d i a l and was  o b t a i n e d by  fluoroscopy.  A sample x-ray was  p r o p e r exposure and p o s i t i o n .  The  hundred MA,  femur  taken t o e n s u r e  exposures were taken u s i n g a  hundred c e n t i m e t e r f o c u s f i l m d i s t a n c e . c o n s t a n t a t one  l a t e r a l condyles o f the  one  Tlie exposure f a c t o r s were k e p t  o n e - t e n t h o f a second a t e i g h t y  Kvp.  Kodak  G film was used with x-omatic screens. The focal spot was  0.6  millimeters. With the femur fixed to the x-ray table, the t i b i a was manually moved by the experimenters from ninety degrees of flexion to f u l l extension i n incremsnts of fifteen to twenty degrees. a medial roentgenogram was taken of the knee joint. maintain the femur i n a constant position.  At each interval, Care was taken to  The oosition of the medial  and lateral femoral condyles was monitored at each exposure to ensure superimposition.  A total of seven medial roentgenograms were taken of  the unbraced knee. The patient was told to s i t up and relax.  The Taylor Brace was  then applied in the previously described manner, and tlie process of x-ray exposures repeated.  Seven medial x-rays were obtained of the  knee joint with the Taylor Brace applied.  The roentgenograms were  then examined and the instant center of rotation calculated for the series of braced and unbraced exposures.  Instant Center of Rotation Calculation  From the study of Kinematics, or the relative motion between rigid bodies called links, we can derive the following statements for the evaluation of a joint: (a)  the bones may be considered to be rigid bodies and to constitute kinematic links (Frankel and Burstein, 1971).  (b)  as one of the links rotates about the other, at amy instant in time there i s a point which has zero velocity and constitutes the instantaneous center of rotation, or centrode.  The  centrode  i s l o c a t e d by i d e n t i f y i n g t h e displacements  o f two  p o i n t s on a limb segment as the segment moves from one p o s i t i o n t o anotner.  The s u c c e s s i v e p o s i t i o n s o f each o f these p o i n t s a r e  i d e n t i f i e d as t n e segment moves and l i n e s a r e drawn c o n n e c t i n g them. These l i n e s r e p r e s e n t t h e s e r i a l t r a n s l a t i o n o f each s e l e c t e d p o i n t . I f p e r p e n d i c u l a r b i s e c t o r s a r e drawn t h r o u g h the l i n e nrLdpoint f o r eacn p a i r o f d i s p l a c e m e n t s , r e p r e s e n t s tlie c e n t r o d e  the i n t e r s e c t i o n o f these b i s e c t o r s  o r instantaneous  p a r t i c u l a r segmental t r a n s l a t i o n  center o f rotation f o r t i a t  (Figure 15).  In c o n s i d e r i n g t h e knee, t h e g u i d i n g a c t i o n o f ligaments and muscles on motion i n t h e s a g g i t a l p l a n e causes a t r a n s l a t i o n o f t h e instantaneous  center f o r successive p o s i t i o n s o f the l i n k s .  A  pathway can t h e r e f o r e be c o n s t r u c t e d a l o n g which tlie i n s t a n t c e n t e r  F i g u r e 15. Centrode l o c a t i o n from t h e movement o f two p o i n t s A, t o A- and B, t o B . Note tiie centrode l o c a t i o n (C) from t h e p e r p e n d i c u l a r b i s e c t o r s . 2  40 moves as the j o i n t goes from flexion to extension  (figure 16).  From the method of Rouleaux (1876) and l a t e r expanded by Frankel, Burstein and Brooks (1971), the instant center o f rotation or centrode may be determined (Appendix E ) .  Figure 16. Instant center of rotation translation from (A) 90° of flexion to (F) 10 of flexion. Note the instant center of rotation pathway (F) for the six successive knee positions. The arrows indicate the joint surface velocity angles at the point of contact between the articulating surfaces.  Stress Analysis  Regulated forces were applied to the knee joint using a mechanical stress apparatus.  Radiographic changes in the laxity of  the knee joint were recorded for unbraced and braced conditions to give an indication of knee stability.  Anterior and medial laxity  measurements were made for each subject with abnormal (unstable) knees.  Anterior  The  Laxity  s u b j e c t was  asked t o assume a s i t t i n g p o s i t i o n on  f a c i n g the d i r e c t i o n o f f o r c e . s e c u r e d f i r m l y t o the and  the  stool.  The The  the  t h i g h o f the s e l e c t e d l e g  knee was  flexed to ninety  ankle s e c u r e d t o the base o f the s t o o l by  stool was  degrees  a stran.  A medial  exDosure o f the r e s t i n g j o i n t was made. A n y l o n s l i n g was  then a p p l i e d t o the n r o x i m a l t i b i a  connected t o a o n e - s i x t e e n t h i n c h s t e e l c a b l e . t o the hand-cranked winch. cable  (Figure  The  cable  The  and  c a b l e was  t e n s i o m e t e r was  connected  aoolied to t i e  17).  F i g u r e 17. M e c h a n i c a l s t r e s s apparatus p o s i t i o n e d f o r a n t e r i o r l a x i t y measurement, j o i n t u n s t r e s s e d . Note the f l e x e d knee p o s i t i o n , the a n k l e s e c u r e d t o the base o f the s t o o l , the c a b l e t e n s i o m e t e r (T) and t i e hand-cranked winch (W).  43  The subject was instructed to relax the muscles of the leg and a gentle pull was exerted on the proximal tibia.  The force was gradually  increased until a twenty pound equivalent reading was obtained on the cable tension indicator.  The hand-cranked winch was then locked and  a medial exposure taken of the stressed knee joint.  The force was  reduced and the subject told to relax. The Taylor Brace was then applied to the knee joint and the knee stressed again to twenty pounds. A third medial exposure was taken and the tension released. The three medial exposures were taken using the Picker Model 6800 S x-ray unit.  Radiation consisted of 400 MA for one-sixth of a second  at eighty Kvp with a bucky screen cassette.  Medial Laxity Tne subject was asked to assume a supine position on the x-ray table with the knees flexed to twenty degrees.  This position was  maintained by sponge wadding. The knees were padded and secured together by a webbed, nylon belt.  The thigh of the selected leg was positioned  in an aluminum thigh cuff and securely fastened to prevent movement (Figure 18) . An antero-posterior exposure was then made of the knee in this resting position. With the thigh of the selected leg gripped firmly i n the aluminum cuff, a nylon sling was applied to the ankle of the leg and connected to a one-sixteentn inch steel cable.  The cable was attached to the  hand-cranked winch and the cable tensicmeber positioned on the cable.  44  F i g u r e 18. Knee p o s i t i o n f o r rnadial l a x i t y ireasurement. Note t h e sponge p a d d i n g between the knees and under tlie knees f o r s u p p o r t and p r o t e c t i o n . The aluminum t h i g h c u f f (/•/) i s s e c u r e l y f a s t e n e d t o p r e v e n t movement.  A gradual valgus  t e n s i o n was then a o p l i e d t o t h e a n k l e .  s u b j e c t was reminded t o r e l a x t h e muscles o f t h e l e g .  The  Tne t e n s i o n  was  i n c r e a s e d u n t i l a twenty pound e q u i v a l e n t r e a d i n g was o b t a i n e d on  tie  cable tension i n d i c a t o r .  The winch was t h e n l o c k e d and an  a n t e r o - p o s t e r i o r exposure o f t i e s t r e s s e d knee j o i n t was made ( F i g u r e The  t e n s i o n was r e l e a s e d and t h e s u b j e c t t o l d t o r e l a x .  19).  The T a y l o r  Brace was then a p p l i e d t o t h e knee j o i n t and t h e knee s t r e s s e d a a a i n t o twenty pounds.  A t h i r d a n t e r o - o o s t e r i o r exoosure was made and tlie  tension  released. Tiie t h r e e a n t e r o - p o s t e r i o r exposures were taken u s i n g t h e P i c k e r Model 6800 S x-ray u n i t .  R a d i a t i o n c o n s i s t e d o f one hundred MA f o r  o n e - s i x t h o f a second a t s e v e n t y - e i g h t  Kvp.  Kodak x-omatic r e g u l a r  i n t e n s i f y i n g s c r e e n s were used.  A l l x-rays were d e v e l o p e d u s i n g  an R.P. X-omatic p r o c e s s o r w i t h t h e " r a p i d p r o c e s s i n g " t e c h n i q u e . A l l x-rays were taken u s i n g Kodak G f i l m .  F i g u r e 19. E x p e r i m e n t a l s e t - u p f o r m e d i a l measurement.  L a x i t y Measurement  laxity  Technique  Anterior Laxity  A n t e r i o r l a x i t y was measured by p l a c i n g exposure A unbraced,  ( f o r the  u n s t r e s s e d knee) w i t h a v e r t i c a l l i n e t a n g e n t i a l t o the  p o s t e r i o r c o n d y l a r s u r f a c e o f the femur and a n o t h e r v e r t i c a l t a n g e n t i a l t o t h e a n t e r i o r s u r f a c e o f the t i b i a l p l a t e a u . procedure was c a r r i e d o u t f o r the unbraced, and f o r the b r a c e d , s t r e s s e d knee  s t r e s s e d knee  (exposure C ) .  line  The same (exposure B)  T i e d i s t a n c e FmTm  was measured and t h e e x c u r s i o n o f the a n t e r i o r s u r f a c e o f t h e t i b i a  46 recorded  in relation  t o the p o s t e r i o r condylar  f o r the t h r e e exposures  ( F i g u r e 20).  V e r n i e r c a l i p e r s and r e c o r d e d  s u r f a c e o f tlie  femur  A l l measurements were made w i t h  t o w i t h i n the nearest  0.10  millimeter  as an i n d i c a t i o n o f a n t e r i o r l a x i t y .  A  B  C  F i g u r e 20. A n t e r i o r l a x i t y measuring technique showing (A) exposure A, unbraced, u n s t r e s s e d ; (B) exposure B, unbraced, s t r e s s e d ; and (C) exposure C, b r a c e d , s t r e s s e d . The d i s t a n c e FmTm was t a k e n as the amount o f a n t e r i o r l a x i t y f o r the s t r e s s e d knee.  Medial Laxity  M e d i a l l a x i t y was measured by p l a c i n g exposure A f o r the unbraced, unstressed  knee w i t h a h o r i z o n t a l l i n e t a n g e n t i a l t o t h e most d i s t a l  47 p o r t i o n s o f the s u b - c h o n d r a l bone o f b o t h f e m o r a l c o n d y l e s . h o r i z o n t a l l i n e was  then drawn t a n g e n t i a l t o t h e most d i s t a l l y p l a c e d  p o r t i o n s o f the s u b - c h o n d r a l bone o f b o t h t i b i a l c o n d y l e s . procedure was  c a r r i e d o u t f o r the unbraced,  s t r e s s e d knee  and f o r the b r a c e d , s t r e s s e d knee (exposure C ) . intra-articular  Another  gap f o r the t h r e e exposures was  m e d i a l s i d e o f the j o i n t  ( F i g u r e 21).  The same (exposure  Tne d i s t a n c e FoTo o r r e c o r d e d f o r the  T h i s d i s t a n c e was  t a k e n as the  amount o f m e d i a l l a x i t y as measured w i t h the V e r n i e r c a l i p e r s t o t h e n e a r e s t 0.10  B)  irdllimeter.  F i g u r e 21. M e d i a l l a x i t y measuring t e c h n i q u e showing (A) unbraced, u n s t r e s s e d ; (B) unbraced, s t r e s s e d ; and (C) b r a c e d and s t r e s s e d knee. The d i s t a n c e FoTo was t a k e n as the amount o f m e d i a l l a x i t y f o r tiie s t r e s s e d knee.  CHAPTER IV RESULTS AND DISCUSSION  Electrogoniometer  Data was and slow,  c o l l e c t e d f o r each s u b j e c t d u r i n g slew, l e v e l  l e v e l r u n n i n g under unbraced  walking  and b r a c e d c o n d i t i o n s .  E l e c t r o g e n i a m e t r i c v a l u e s were c a l c u l a t e d f o r knee f l e x i o n - e x t e n s i o n , i n t e r n a l - e x t e r n a l r o t a t i o n and v a r u s - v a l g u s . f o r each s u b j e c t from the average  Values were  determined  of five steps.  Tne summary o f r e s u l t s f o r S u b j e c t A w i t h normal ( s t a b l e ) knees i s p r e s e n t e d f o r slow, and f o r slow,  l e v e l walking  l e v e l running  (Table 1, F i g u r e s 22-A  (Table 2, F i g u r e s 23-A  and  and 23-3},..  22-3) Values  f o r the b r a c e d knee were r e c o r d e d u s i n g the T a y l o r Brace. The r e s u l t s from two s u b j e c t s (B and C) w i t h abnormal knees are p r e s e n t e d f o r slow, 24-A,  24-3,  F i g u r e s 25-A,  26-A,  26-B)  25-B,  27-A,  l e v e l walking  (Tables 3 and 5, F i g u r e s  and f o r slow, l e v e l r u n n i n g 27-B).  (unstable)  (Tables 4 and  A l l b r a c e d r e s u l t s were r e c o r d e d  w i t h the T a y l o r Brace a p p l i e d . Comparison v a l u e s from S u b j e c t D w i t h an abnormal knee are p r o v i d e d f o r slow, l e v e l w a l k i n g and slow, (Table 7, F i g u r e s 28-A,  28-B  (unstable)  level  and T a b l e 8, F i g u r e s 29-A  running  and 29-B).  A l l b r a c e d r e s u l t s were r e c o r d e d w i t h the use o f the L e n n o x - H i l l D e - r o t a t i o n a l Brace.  6,  TABLE I Average v a l u e s o f knee motion (degrees) for  d u r i n g slow l e v e l w a l k i n g  S u b j e c t A w i t h normal ( s t a b l e ) knees  UNBRACED l e f t knee  BRACED  r i g h t knee  l e f t knee  r i g h t knee*  Flexion-extension  74°  75°  75°  64°  Internal-external rotation  10°  8°  11°  6°  Varus-valgus  15°  12°  15°  7°  * i n d i c a t e s knee b r a c e d w i t h T a y l o r Brace  TABLE  II  Average v a l u e s o f knee motion (degrees) for  d u r i n g slow l e v e l  running  S u b j e c t A w i t h normal ( s t a b l e ) knees  UNBRACED  Flexion-extension Internal-external Varus-valgus  rotation  BRACED  l e f t knee  r i g h t knee  l e f t knee  75°  105°  75°  82°  15°  20°  15°  18°  15°  20°  16°  17°  * i n d i c a t e s knee b r a c e d w i t h T a y l o r Brace  r i g h t knee*  50  40°  \I\AAAA\ l e f t knee  Flexion  Extension  /\i/\*/WV*A.  r i g h t knee  l e f t knee  r i g h t knee  10° 0° 10°  l e f t knee  r i g h t knee  F i g u r e 22-A. E l e c t r o g o n i o m a t r i c t r a c i n g s * o f S u b j e c t A w i t h normal ( s t a b l e ) knees d u r i n g unbraced, slow, l e v e l w a l k i n g . Zero l i n e r e p r e s e n t s the p o s i t i o n o f t h e knee a t n e u t r a l stance. * due t o a l a c k o f c l a r i t y i n t h e o r i g i n a l , freehand t r a c i n g s have been used i n some c a s e s .  51  40  v  AAAAA  Flexion  Intension  VWUWUU _  Int.  rot n  Ext.  rot'n  bright  Jleft  knee  knee  1  _  _  _Jright  left  knee  knee  Varus Ir i g h t  Valgus  F i g u r e 22-B Electrogoniometric tracings of Subject A with normal (stable) knees d u r i n g s l o w , l e v e l w a l k i n g w i t h t h e T a y l o r B r a c e on t h e r i g h t knee.  knee  F i g u r e 23-A. normal  Electrogoniometric tracings of Subject A with  ( s t a b l e ) knees d u r i n g unbraced, slow, l e v e l  running.  53  Figure  23-B.  Electrcigcniometric tracings o f Subject A with  normal ( s t a b l e ) knees d u r i n g Brace on r i g h t  knee.  slow, l e v e l r u n n i n g w i t h  Taylor  Results Table 1 (walking subject with normal (stable) knees, i n a comparison of the unbraced and braced columns, shows a reduction i n the range of movement values for the right knee of 11° for flexion-extension (75° to 64°); of 2° for internal-external rotation (8° to 6°) and of 5° for varus-valgus (12° to 7°) following application of the Taylor Brace. The left, unbraced knee range shows a slight increase of 1° i n flexion-extension (74° to 75°); an increase of 1° in internal-external rotation (10° to 11°) and remained the same at 15° of varus-valgus movement. Table 2 (running subject with normal (stable) knees), i n a comparison of the unbraced and braced columns, shows a reduction i n the range of movement values for the right knee of 23° for flexion-extension (105° to 82°); of 2° for internal-external rotation (20° to 18°) and of 3° for varus-valgus (20° to 17°). Tne l e f t , unbraced knee range remained consistent for flexion-extension at 75°,  for internal-external rotation at 15° and increased 1°  (15" to 16") of varus-valgus movement. The increased speed of ambulation produced a net decrease i n the range of flexion-extension for the right, braced knee of 11° (for a slow, level walk), to 23° (for a slow, level run). The net decrease i n the range of internal-external rotation and varus-valgus for the right, braced knee remained the same following an increase  in the speed of ambulation (2° vs 2° and 5° vs 3°). The magnitude of the recorded values, however, increased from 6° to 18° for internal-external rotation and from 7° to 17° for varus-valgus. The range of movement for the l e f t , unbraced knee after apnlication of the Taylor Brace to the right knee remained consistent  (See Table 1). Similarly, when the speed of ambulation  increased, there was very l i t t l e change i n the range of movement values (Table 2).  TABLE I I I Average v a l u e s o f knee motion (degrees) d u r i n g slow l e v e l w a l k i n g for  S u b j e c t B w i t h abnormal (unstable) knee  UNBRACED  BRACED  l e f t knee  r i g h t knee  l e f t knee*  r i g h t knee  Flexion-extension  80°  79°  66°  80°  Internal-external rotation  23°  16°  12  16  Varus-valgus  13°  19°  5°  19°  * i n d i c a t e s knee b r a c e d w i t h T a y l o r Brace  TABLE IV Average v a l u e s o f knee motion (degrees) d u r i n g slow l e v e l r u n n i n g for  S u b j e c t B w i t h abnormal (unstable) knee  UNBRACED  BRACED  l e f t knee  r i g h t knee  Flexion-extension  93°  100°  97°  105°  Internal-external rotation  25°  25°  16°  31°  Varus-valgus  16°  25°  7°  20°  * i n d i c a t e s knee b r a c e d w i t h T a y l o r Brace  l e f t knee*  r i g h t knee  57  40^  l e f t knee  Flexion  r i q h t knee Extension 10° 0° 10°  l e f t knee  I n t . rot'n  r i q h t knef  Ext. r o t ' n  l e f t knee  r i g h t knee  Figure 24-A. ;Electrogoniometric t r a c i n g s of Subject i i w i t h abnormal (unstable) knee during unbraced, slow, l e v e l walking. Zero l i n e represents the p o s i t i o n of tne knee a t n e u t r a l stance. :  58  l e f t knee  r i g h t knee  r i g h t knee Int.  rot'n  F i g u r e 24-3. E l e c t r o g o n i o m e t r i c t r a c i n g s o f S u b j e c t R w i t h abnormal (unstable) knee d u r i n g slow, l e v e l w a l k i n g w i t h tlie T a y l o r 3 r a c e on the l e f t knee.  59  F i g u r e 25-A. Elec±rcigoniorretric t r a c i n g s o f S u b j e c t B wit-i abnormal (unstable) knee d u r i n g unbraced, slew, l e v e l r u n n i n g .  60  l e f t knee  Flexion  i g n t knee  Extension l e f t knee Int. r o t r i c h t knee Ext. r o t  1  l e f t knee 10 Varus  r i g h t knee  Valgus'  F i g u r e 25-B, E l e c t r o g o n i o i r e t r i c t r a c i n g s o f S u b j e c t B w i t h abnormal (unstable) knee d u r i n g slow, l e v e l ^running w i t h t h e T a y l o r Braoe on the l e f t knee. .  61  Results  T a b l e 3 (walking s u b j e c t w i t h abnormal (unstable) knee), comparison o f the unbraced  and b r a c e d columns, shows a r e d u c t i o n i n  the range o f movement v a l u e s f o r t h e l e f t knee o f 14° flexion-extension (23°  t o 12°)  (80°  in a  t o 66°);  o f 11°  and o f 8° f o r v a r u s - v a l g u s  a p p l i c a t i o n o f the T a y l o r B r a c e .  The  for  for internal-external rotation (13°  t o 5°) f o l l o w i n g  r i g h t , unbraced knee range  shows a s l i g h t i n c r e a s e o f 1° i n f l e x i o n - e x t e n s i o n (79°  to  89°);  and m a i n t a i n e d tne same v a l u e s f o r i n t e r n a l - e x t e r n a l r o t a t i o n and v a r u s - v a l g u s  (16°)  (19°).  T a b l e 4 ( r u n n i n g s u b j e c t w i t h abnormal (unstable) knee), i n a comparison o f the unbraced  and b r a c e d columns, shows an i n c r e a s e i n  tiie range o f movement v a l u e s f o r t h e l e f t knee o f 4° f o r f l e x i o n - e x t e n s i o n (93°  t o 97°);  v a l u e s o f 9° 9°  (16°  a decrease i n t h e range o f i n t e r n a l - e x t e r n a l (25°  t o 7°).  t o 16°) The  rotation  and a d e c r e a s e i n t h e v a r u s - v a l g u s range o f  r i g h t , unbraced knee range showed an i n c r e a s e o f  5° f o r f l e x i o n - e x t e n s i o n (100° t o 105°); an i n c r e a s e o f 6° f o r internal-external rotation varus-valgus  (25°  to  (25°  t o 31°)  and a decrease o f 5° f o r  20°).  The range o f f l e x i o n - e x t e n s i o n o f the l e f t , b r a c e d knee reduced 14° i n a s u b j e c t w a l k i n g s l o w l y on t h e l e v e l .  was  These r e s u l t s  are c o n s i s t e n t w i t h t h e r e s u l t s o f the normal ( s t a b l e ) knee f o r slow, l e v e l w a l k i n g where a r e d u c t i o n o f 11° was speed o f ambulation  recorded.  I n c r e a s i n g the  from a slow, l e v e l walk t o a slow, l e v e l run  62  produced an increase i n the flexion-extension range of 4 l e f t , braced knee.  W  for the  These results are not consistent with the results  from the normal (stable) knee where a decrease of 23° i n the flexion-extension range was recorded. There was a consistent net decrease i n the range of internal-external rotation for the l e f t , braced knee of 11° for a slow-walking subject and of 9° for a slew-running subject.  There was also a consistent net  decrease i n the range of varus-valgus for the l e f t , braced knee of 8° in a walking subject and of 9° i n a running subject. The range of movement of the right, unbraced knee remained the same following application of the Taylor Brace to tlie l e f t knee of the walking subject.  An increase i n the speed of ambulation, however, to  a slow, level run resulted i n increases i n the range of flexion-extension of 5° (100° to 105°); and i n tlie range of internal-external rotation of 6° (25° to 31°). The range of varus-valgus decreased 5° (25° to 20°) for the right, unbraced knee following application of tie Taylor Brace to the l e f t knee of the slow-running subject.  63  TABLE V Average v a l u e s o f knee m o t i o n (degrees) d u r i n g s l e w l e v e l w a l k i n g f o r S u b j e c t C w i t h abnormal ( u n s t a b l e )  knee  UNBRACED  BRACED  l e f t knee  r i g h t knee  l e f t knee  r i g h t knee*  Flexion-extension  90°  80°  85°  56°  Internal-external rotation  20°  18°  25°  9°  Varus-valgus  10°  11°  8°  10°  * i n d i c a t e s knee b r a c e d w i t h T a y l o r B r a c e  TABLE VI Average v a l u e s o f knee m o t i o n (degrees) d u r i n g s l o w l e v e l r u n n i n g f o r S u b j e c t C w i t h abnormal (unstable)  knee  UNBRACED  BRACED  l e f t knee  r i g h t knee  l e f t knee  Flexion-extension  90°  86°  86°  59°  Internal-external rotation  23°  21  30°  11  Varus-valgus  10°  11°  7°  11°  * i n d i c a t e s knee b r a c e d w i t h T a y l o r B r a c e  r i g h t knee*  64  l e f t knee  ^^^^ Varus  r i g h t knee  Valgus  l e f t knee  Int.  rot'n  r i g h t knee  Ext. rot'n  1  L v ^ L ! l e f t knee  Flexion  r i g h t knee Extension  4  il  F i g u r e 26-A. E l e c t r o g c n i o m e t r i c t r a c i n g s * o f S u b j e c t C w i t h abnormal (unstable) knee d u r i n g unbraced, S l a v , l e v e l walking. Zero l i n e r e p r e s e n t s t h e p o s i t i o n o f the knee a t n e u t r a l s t a n c e . Each l i n e r e p r e s e n t s f i v e degrees o f movement. *  original  65  L e f t knee  Varus  r i g h t knee  Valgus  ft...  ;  Int.  l e f t knee  rot'n r i g h t knee  Ext.rot'n / • -<  l e f t knee 'HT-  . up-  Flexion  '** .;" >.,  '  -~  ...  -j~ "  J .- i ' .  11  'p  - " T V " " '• 'j _\_...... . ./  •'*'"' i*.' ' „„ " ;  X .  . . .  t"  V. • / "  Extension  F i g u r e 26^B. E l e c t r o g o n i o m e t r i c t r a c i n g s o f S u b j e c t C w i t h abnormal (unstable) knee d u r i n g slow, l e v e l w a l k i n g w i t h the T a y l o r B r a c e on the r i g h t knee.  r i g h t knee  66  l e f t knee  Varus  r i g h t knee  Valgus  If."  Int.  rot'n  Ext. rot'n  111  "- r e : r v  --•-~_ I V  l e f t knee  ricrht knee  y; .v.' c.  .r "Y"T.  , ^ t r ^ : i : - ^ l e f t knee  Flexion  \l  7- \ -  —- U"-A--" - - -'- \ •/  r i q h t knee Extension  F i g u r e 27-A. Electrogoniometric tracings o f Subject C w i t n abnormal (unstable) knee d u r i n g unbraced, slew, l e v e l running.  67  l e f t knee  Varus v.  Valgus  r i g h t knee  '  ."/\.:  l e f t knee  Int.  rot'n r i g h t knee  Ext. rot'n  -cwz^-^w; •I i -/ •  r  -  r  - -  y  - j  .  • | -j-  y..;y  i f  - vft" /...A  ^ y  l e f t knee  Flexion  r i g h t knee Extension  F i g u r e 27-B. E l e c t r o g o n i o i r e t r i c t r a c i n g s o f S u b j e c t C w i t h abnormal (unstable) knee d u r i n g slow, l e v e l r u n n i n g w i t h t h e T a y l o r Brace on t h e r i g h t knee.  68  Results  T a b l e 5 (walking s u b j e c t w i t h abnormal (unstable) k n e e ) , i n a comparison  o f the unbraced and b r a c e d columns, shows a r e d u c t i o n i n  the range o f movement v a l u e s f o r the r i g h t knee o f 24° f o r flexion-extension  (80° t o 56°); o f 9° f o r i n t e r n a l - e x t e r n a l  (18° t o 9°) and o f 1° f o r v a r u s - v a l g u s a p p l i c a t i o n o f the T a y l o r Brace.  (11  rotation  t o 10 ) f o l l o w i n g  The l e f t , unbraced knee range  shows a s l i g h t decrease o f 5° i n f l e x i o n - e x t e n s i o n , a s l i g h t i n c r e a s e of  5° i n i n t e r n a l - e x t e r n a l r o t a t i o n and a decrease i n v a r u s - v a l q i i s  of  2° (10° t o 8°). T a b l e 6 (running s u b j e c t w i t h abnormal (unstable) knee), i n a  comparison  o f the unbraced  and b r a c e d columns, shows a decrease i n the  range o f movement v a l u e s f o r the r i g h t knee o f 27° f o r f l e x i o n - e x t e n s i o n (86° t o 59°); o f 10° f o r i n t e r n a l - e x t e r n a l r o t a t i o n of  z e r o i n the v a r u s - v a l g u s v a l u e o f 11°.  fluctuated s l i g h t l y  internal-external rotation  The  unbraced  knee  f o l l o w i n g a n p l i c a t i o n o f the T a y l o r Brace  d e c r e a s i n g 4° i n f l e x i o n - e x t e n s i o n . ( 9 0 °  varus-valgus  The l e f t ,  (21° t o 11°) and  t o 86°); i n c r e a s i n g 7° i n  (23° t o 30°) and d e c r e a s i n g 3° i n  (10° t o 7°).  range o f f l e x i o n - e x t e n s i o n o f the r i g h t , b r a c e d knee  c o n s i s t e n t l y d e c r e a s e d from t h e unbraced  range d r o p p i n g 24° i n t h e  w a l k i n g s u b j e c t and 27° i n the r u n n i n g s u b j e c t .  There was a  c o n s i s t e n t decrease i n the i n t e r n a l - e x t e r n a l r o t a t i o n range o f the  r i g h t , b r a c e d knee o f 9 ° and o f 10°  ( f i f t y percent)  ( f o r t y - s e v e n peroent)  unbraced v a l u e s .  There was  f o r the w a l k i n g s u b j e c t  f o r the r u n n i n g s u b j e c t , f r o n t i e  very l i t t l e  f l u c t u a t i o n i n the  magnitude o f the i n t e r n a l - e x t e r n a l r o t a t i o n range, however, k e e p i n g c o n s t a n t v a l u e s d e s p i t e the i n c r e a s e i n t h e speed o f  ambulation.  These r e s u l t s were c o n s i s t e n t w i t h t h e r e s u l t s o f S u b j e c t B  who  showed d e c r e a s e s o f f o r t y - s e v e n p e r c e n t and t a i r t v - s i x p e r c e n t r e s p e c t i v e l y i n i n t e r n a l - e x t e r n a l r o t a t i o n v a l u e s f o r the b r a c e d knee. The v a r u s - v a l g u s v a l u e s o f the r i g h t knee f l u c t u a t e d v e r / a f t e r b r a c i n g , r e d u c i n g o n l y 1 ° d u r i n g slow, l e v e l w a l k i n g remaining the same d u r i n g slow, l e v e l  running.  little and  TABLE  VII  Average values o f knee motion (degrees) during slaw l e v e l walking for Subject D with abnormal (unstable) knee  UNBRACED  BRACED  l e f t knee  r i g h t knee  l e f t knee  r i g h t knee*  Flexion-extension  85°  79°  85°  60°  Internal-external rotation  15°  27°  13°  5°  Varus-valgus  13°  8°  15°  7°  * indicates knee braced with Lennox-Hill De-rotational Brace  TABLE V I I I Average v a l u e s o f knee motion (degrees) d u r i n g slow l e v e l for  running  S u b j e c t D w i t h abnormal (unstable) knee  UNBRACED  BRACED  l e f t knee  r i g h t knee  l e f t knee  r i g h t knee*  Flexion-extension  95°  96°  85°  69°  Internal-external rotation  20°  28°  18°  10°  Varus-valgus  14°  11°  16°  7°  * i n d i c a t e s knee b r a c e d w i t h L e n n o x - H i l l D e - r o t a t i o n a l Brace  71  F i g u r e 28-A. Elec±rogoniometric t r a c i n g s o f S u b j e c t D w i t h abnormal (unstable) knee d u r i n g unbraced, slow, l e v e l walking. Zero l i n e r e p r e s e n t s t h e p o s i t i o n o f t h e knee a t n e u t r a l s t a n c e . Each l i n e r e p r e s e n t s f i v e degrees o f movement.  72  eft knee  Lght knee  ^^^^; ;^, , ,^ ,,,,,,, M  I I  I  ^^^'''^'Vf  ) )  '""•I'l^"*'!'!!!^!!!!  l e f t knee  Hill  rot'n^o  riant knee  rot'n  .. . .  / —-V--  ...  /  7  / _ "  \ •  t—  l e f t knee  on  riaht knee  sion  Figure 28-B. Electrogoniometric tracings of Subject D with abnormal (unstable) knee during slow, level walking with the Lennox-Hill De-rotational Brace cn the right knee.  F i g u r e 29-A. Hlectrogoniometric tracings of Subject D with abnormal (unstable) knee d u r i n g unbraced, slow, l e v e l running.  74  left  knee  r i a n t knee jus  l e f t knee  rot'n  o  r i g h t knee  rot n  l e f t knee  xion  r i g h t knee ension  F i g u r e 29-B. E l e c t r o g o n i o m e t r i c t r a c i n g s o f S u b j e c t D w i t h abnormal (unstable) knee d u r i n g slow, l e v e l r u n n i n g w i t h the L e n n o x - H i l l D e - r o t a t i o n a l Brace on the r i g h t Jcnee.  75  Results  T a b l e 7 (walking s u b j e c t w i t h abnormal (unstable) knee), i n a comparison o f t h e unbraced  and b r a c e d columns, shows a r e d u c t i o n i n the  range o f movement v a l u e s f o r the r i g h t knee o f 19° (79°  t o 60°);  o f 22°  for internal-external rotation  1° f o r v a r u s - v a l g u s  (8° t o 7°)  De-rotation Brace.  The  (15°  t o 13°)  (27°  t o 5°)  and o f  f o l l o w i n g a p p l i c a t i o n o f the L e n n o x - H i l l  l e f t , unbraced  c o n s t a n t f o r f l e x i o n - e x t e n s i o n a t 85°; rotation  for flexion-extension  knee range v a l u e s remained d e c r e a s e d 2° f o r i n t e r n a l - e x t e r n a l  and i n c r e a s e d 2° f o r v a r u s - v a l g u s  (13°  t o 15°). .  T a b l e 8 (running s u b j e c t w i t h abnormal (unstable) knee), i n a comparison o f the unbraced  and b r a c e d columns, shows a decrease i n the  range o f movement v a l u e s f o r the r i g h t knee o f 27° (96°  t o 69°);  (28°  t o 10°)  a d e c r e a s e o f 18°  for flexion-extension  for internal-external  and a decrease o f 4° f o r v a r u s - v a l g u s  rotation  (11°  t o 7°).  The  l e f t , unbraced knee v a l u e s f l u c t u a t e d f o l l o w i n g a p p l i c a t i o n o f the L e n n o x - H i l l D e - r o t a t i o n B r a c e , d e c r e a s i n g 10° (95°  t o 85°);  i n flexion-extension  d e c r e a s i n g 2° i n i n t e r n a l - e x t e r n a l r o t a t i o n  and i n c r e a s i n g 2°  (14°  t o 16°)  (20°  to  18°)  i n v a r u s - v a l g u s movement.  The range o f f l e x i o n - e x t e n s i o n o f the r i g h t , b r a c e d knee c o n s i s t e n t l y d e c r e a s e d from the unbraced w a l k i n g s u b j e c t and 27°  range d r o p p i n g 19°  i n the running s u b j e c t .  i n the  The r e d u c t i o n i n  the r e c o r d e d v a l u e s f o r i n t e r n a l - e x t e r n a l r o t a t i o n were t h e g r e a t e s t f o r the w a l k i n g s u b j e c t a t 22° t o 18°  ( s i x t y - f o u r percent)  (eighty-one p e r c e n t )  i n the r u n n i n g s u b j e c t .  and were  reduced  Varus-valgus  values during  f l u c t u a t e d very l i t t l e  i n c r e a s i n g 1° d u r i n g w a l k i n g and  4°  running.  Walking w i t h  the L e n n o x - H i l l D e - r o t a t i o n a l Brace on the  right  knee o f S u b j e c t D d i d n o t g r e a t l y a l t e r the range o f the c o n t r a - l a t e r a l knee.  Running, however, d e c r e a s e d f l e x i o n - e x t e n s i o n by  d e c r e a s e d i n t e r n a l - e x t e r n a l r o t a t i o n by 2° and , by  10°,  increased  varus-valgus  _.o  2 .  Discussion  A l l s u b j e c t s t e s t e d w i t h t h e T a y l o r B r a c e under c o n d i t i o n s  of  slow, l e v e l w a l k i n g showed an o v e r a l l r e d u c t i o n i n the range o f f l e x i o n - e x t e n s i o n o f the b r a c e d knee (Subject A, S u b j e c t C,  24°).  11°;  S u b j e c t B,  I n c r e a s i n g the speed o f ambulation t o a slow,  14°; level  run produced a f u r t h e r d e c r e a s e i n the f l e x i o n - e x t e n s i o n range o f b r a c e d knee ( S u b j e c t A, 23°; S u b j e c t B who  recorded  S u b j e c t C,  27°),  an i n c r e a s e o f 4°.  with  Results  the e x c e p t i o n from S u b j e c t  the of  D  ( L e n n o x - H i l l D e - r o t a t i o n a l Brace) showed s i m i l a r f i n d i n g s w i t h d e c r e a s e s o f 19°  f o r slow, l e v e l w a l k i n g and  27°  f o r slow,  level  running. With the e x c e p t i o n  of Subject B  ( f o r slow, l e v e l r u n n i n g ) , i t  appears t h a t the T a y l o r B r a c e i s h a v i n g  a r e s t r a i n i n g e f f e c t on  dynamic f l e x i o n - e x t e n s i o n range o f the b r a c e d knee t h a t i n magnitude as the speed o f ambulation i n c r e a s e s . s i m i l a r i n magnitude t o the r e d u c t i o n produced by  the  increases  This e f f e c t i s the  Lennox-Hill  77  D e - r o t a t i o n a l Brace. A l l s u b j e c t s t e s t e d w i t h the T a y l o r Brace under c o n d i t i o n s o f slow, l e v e l walking  shewed an o v e r a l l r e d u c t i o n i n t h e range o f i n t e r n a l - e x t e r n a l  r o t a t i o n o f t h e b r a c e d knee ( S u b j e c t A, 2°; 9°).  S u b j e c t 3,  11°;  Subject  C,  I n c r e a s i n g the speed o f ambulation t o a slow, l e v e l run p r o d u c e d  minor f l u c t u a t i o n s i n the i n t e r n a l - e x t e r n a l r o t a t i o n range o f b r a c e d knee S u b j e c t A who  ( S u b j e c t B,  9°;  S u b j e c t C,  remained the same a t 2°.  10°)  the  w i t h the e x c e p t i o n  R e s u l t s from S u b j e c t  of  D  ( L e n n o x - H i l l D e - r o t a t i o n a l Brace) showed s i m i l a r f i n d i n g s w i t h d e c r e a s e s f o r i n t e r n a l - e x t e r n a l r o t a t i o n o f 22° walking  and  18°  f o r slow, l e v e l  (normal, s t a b l e knee) i t appears  a r e s t r a i n i n g e f f e c t on the dynamic  i n t e r n a l - e x t e r n a l r o t a t i o n range o f t h e b r a c e d knee. e f f e c t i s constant  level  running.  With the e x c e p t i o n o f S u b j e c t A t h a t t h e T a y l o r Brace i s h a v i n g  f o r slow,  This restraining  (with minor f l u c t u a t i o n s ) d e s p i t e i n c r e a s e s i n the  magnitude o f the r o t a t i o n measurements as a r e s u l t o f i n c r e a s e s i n the speed o f ambulation.  A p p l i c a t i o n o f the T a y l o r Brace t o the  abnormal (unstable) knees o f S u b j e c t s B and C reduced, the h i g h r o t a t o r y v a l u e s f o r slow, l e v e l w a l k i n g  t o w i t h i n the range r e c o r d e d  normal ( s t a b l e ) , unbraced knee (Subject A)  f o r slow, l e v e l  from the walking.  T h i s e f f e c t i s s i m i l a r i n magnitude t o t h e r e d u c t i o n produced by L e n n o x - H i l l D e - r o t a t i o n a l Brace on i n t e r n a l - e x t e r n a l r o t a t i o n . A l l s u b j e c t s t e s t e d w i t h the T a y l o r B r a c e under c o n d i t i o n s o f slow, l e v e l w a l k i n g  showed an o v e r a l l r e d u c t i o n i n the range o f  the  v a r u s - v a l g u s o f the b r a c e d knee ( S u b j e c t A, S u b j e c t C, 1°).  yJ  S u b j e c t B,  I n c r e a s i n g t h e speed o f ambulation  run p r o d u c e d s i m i l a r decreases b r a c e d knee ( S u b j e c t A, S u b j e c t C who  5;  i n the v a r u s - v a l g u s  3°; S u b j e c t B,  r e c o r d e d no change.  8; W  t o a slow,  level  range o f the  9°), w i t h the e x c e p t i o n o f  R e s u l t s from S u b j e c t D  ( L e n n o x - H i l l D e - r o t a t i o n a l Brace) shaved s i m i l a r f i n d i n g s w i t h decreases o f 1° f o r slow, l e v e l w a l k i n g and 4° f o r slow, l e v e l running. With the e x c e p t i o n o f S u b j e c t C, i t appears t h a t the T a y l o r Brace i s h a v i n g a r e s t r a i n i n g e f f e c t an the dynamic v a r u s - v a l g u s b r a c e d knee.  I n one  range o f the  s u b j e c t (B), t h i s r e s t r a i n i n g e f f e c t i n c r e a s e d i n  magnitude w i t h the speed o f ambulation.  The  r e s u l t s from S u b j e c t B  a r e s i m i l a r t o t h e r e d u c t i o n p r o d u c e d by t h e L e n n o x - H i l l D e - r o t a t i o n a l Brace on  varus-valgus.  A p p l i c a t i o n o f the T a y l o r Brace under c o n d i t i o n s o f slow, w a l k i n g p r o d u c e d minor f l u c t u a t i o n s i n t h e range o f the (unbraced) knee ( S u b j e c t A, r o t a t i o n ; S u b j e c t B, S u b j e c t C who  1° f l e x i o n - e x t e n s i o n , 1°  level  contra-lateral  internal-external  1° f l e x i o n - e x t e n s i o n ) w i t h t h e e x c e p t i o n o f  r e c o r d e d major f l u c t u a t i o n s i n the range o f a l l t h r e e  movement parameters.  I n c r e a s i n g the speed o f ambulation  l e v e l run produced major f l u c t u a t i o n s i n the range o f the  t o a slow, contra-lateral  (unbraced) knee ( S u b j e c t B, S u b j e c t C) w i t h the e x c e p t i o n o f S u b j e c t who  r e c o r d e d minor f l u c t u a t i o n s o f 1° i n t h e v a r u s - v a l g u s  R e s u l t s from S u b j e c t D  range.  ( L e n n o x - H i l l D e - r o t a t i o n a l Brace) showed  s i m i l a r f i n d i n g s w i t h minor f l u c t u a t i o n s f o r slow, l e v e l w a l k i n g  and  A  major fluctuations f o r slow, l e v e l running. With the exception o f Subject C, i t appears that the Taylor Brace os having very l i t t l e e f f e c t on the dynamic range of the (unbraced) knee f o r slow, l e v e l walking.  contra-lateral  Increasing the speed of  ambulation to a slow, l e v e l run appears to produce major fluctuations i n the range of the c o n t r a - l a t e r a l knee f o r both subjects with unstable knees (Subjects B and C).  This e f f e c t i s s i m i l a r t o the fluctuations  produced by the Lennox-Hill De-rotational Brace.  Instant Center of Rotation  Data was c o l l e c t e d f o r each subject from the unstable knee under unbraced and braced conditions.  A t o t a l of s i x roentgenograms were  taken and the instant center calculated f o r the series from ninety degrees of f l e x i o n t o zero degrees of f l e x i o n .  Each subject assumed  a p o s i t i o n l y i n g on the side with the selected knee non-'weightbearing. The summary of r e s u l t s i s presented f o r the instant center o f rotation pathways (Figures 30 and 31).. J o i n t surface velocity angles are shown f o r the s i x calculated instant centers f o r each subject from zero degrees of f l e x i o n (number six) to ninety degrees of f l e x i o n (number one) Tables 9-A, 9-3, 10-A and 10-B).  80  l i i  • '.6 I  unbraced circle diameter 4.6 centimeters  braced circle diameter 3.5 centimeters Figure 30. Pathway of instant center of rotation with respect to the t i b i a and femur for Subject B, l e f t knee, unstable. Scale i s approximately one third.  81  Angle o f Joint  90°  75°  60°  40°  20°  •10°  VelocityAngle (unbraced)  90°  76°  107°  90°  88°  90°  T a b l e 9-A. J o i n t surface v e l o c i t y angles, S u b j e c t B, u n s t a b l e knee, unbraced.  .Angle o f Joint  ^QO  Velocity (braced)  Angle o g 8  75°  60°  40°  20°  10°  90°  96°  90°  94°  90°  T a b l e 9-B. J o i n t surface velocity S u b j e c t B, u n s t a b l e knee, b r a c e d .  angles,  unbraced circle diameter 1.65 centimeters  i  vi  braced circle diameter 2.20 centimeters Figure 31. Pathway of instant center of rotation with respect to tlie t i b i a and femur for Subject C, right knee, unstable. Scale i s approximately one third.  83  Angle of Joint  9 Q  o  Velocity Angle^o (unbraced)  75°  60°  40°  20°  10°  90°  90°  90°  107°  96°  Table 10-A. Joint surface velocity angles, Subject C, unstable knee, unbraced.  Angle of Joint  90°  75°  60°  40°  20°  10°  Velocity Angle^o (braced)  90°  . 90°  91°  116°  90°  Table 10-B. Joint surface velocity angles, Subject C, unstable knee, braced.  Results  Results from both subjects (Figures 30 and 31) shew that the instant centers f o r the s i x .different knee angles are located i n the posterior portion of the medial femoral condyle.  The results also  show that there i s no standard pattern t o the instant center pathway for the abnormal, unbraced knee.  The instant center movement i n the  posterior portion of the medial femoral condyle i s quite random. There was a tendency f o r the instant center pathway to move p o s t e r i o r l y and superiorly following application of the Taylor Brace that was consistent f o r both subjects. For Subject B, the location of the instant center f o r the s i x d i f f e r e n t knee angles f e l l within a c i r c l e with a diameter of centimeters.  Following application of the Taylor Brace, the c i r c l e  diameter was reduced to 3.50  centimeters.  These findings were not  consistent with Subject C who showed an increase i n c i r c l e from 1.65  4.60  centimeters to 2.20  diameter  centimeters following application of  the Taylor Brace. The j o i n t surface v e l o c i t y angles were judged to Joe abnormal i n both of the subjects tested.  Subject B showed abnormal v e l o c i t y  angle values with impingement t o f l e x i o n between s i x t y and seventy-five degrees i n c l u s i v e (Table 9-A).  Application of the Taylor Brace to  Subject B resulted i n values i n d i c a t i v e o f r e l a t i v e l y free g l i d i n g at the a r t i c u l a r surfaces with no r e s t r i c t i o n t o f l e x i o n (Table 9-B). Subject C showed r e l a t i v e l y free knee motion throughout the e n t i r e  unbraced range e x c e p t f o r the l a s t abnormal v a l u e s were n o t e d  few degrees o f e x t e n s i o n where  (Table 10-A).  A p p l i c a t i o n o f the T a y l o r  Brace i n c r e a s e d the abnormal v a l u e s i n t h i s range.  Discussion  Both s u b j e c t s t e s t e d w i t h the T a y l o r Brace l o c a t e d the i n s t a n t c e n t e r o f r o t a t i o n pathway i n the p o s t e r i o r o o r t i o n o f the m e d i a l femoral c o n d y l e .  These r e s u l t s are c o n s i s t e n t w i t h the f i n d i n g s o f  r e l a t e d researchers  ( F r a n k e l and B u r s t e i n , 1971;  Martens and Temets, 1975).  Smidt, 1972;  Meek,  There appears t o be no s e t p a t t e r n t o  t h i s pathway f o r the abnormal (unstable) knee b u t , r a t h e r , random movement on the c o n d y l a r s u r f a c e .  Meek e t a l (1975) and Walker (1973)  have r e p o r t e d s i m i l a r r e s u l t s f o r abnormal knee pathways.  For both  o f the s u b j e c t s t e s t e d , the i n s t a n t c e n t e r pathway moved p o s t e r i o r l y and s u p e r i o r l y f o l l o w i n g a p p l i c a t i o n o f the T a y l o r B r a c e . Both o f the s u b j e c t s t e s t e d shewed an a l t e r a t i o n i n the p a t t e r n and c i r c l e diameter o f the i n s t a n t c e n t e r o f r o t a t i o n pathway a f t e r a p p l i c a t i o n o f the T a y l o r B r a c e .  There was  not, however,  any  c o n s i s t e n c y i n the p a t t e r n s o f any s u b j e c t n o r i n tne change o f diameter.  Subject B recorded  Subject C recorded  circle  a decrease i n c i r c l e diameter w h i l e  an i n c r e a s e f o l l o w i n g b r a c i n g .  I t appears t h a t a p p l i c a t i o n o f the T a y l o r Brace t o the  unstable  knee produces changes i n the p a t t e r n and d i s p e r s i o n o f the i n s t a n t c e n t e r o f r o t a t i o n pathway t h a t has no d e f i n i t e t r e n d .  There does  appear, however, t o be a d e f i n i t e s h i f t i n g o f the i n s t a n t c e n t e r pathway p o s t e r i o r l y and s u p e r i o r l y f o l l o w i n g b r a c i n g .  Both s u b j e c t s t e s t e d showed abnormal j o i n t s u r f a c e angles  (Tables 9-A  and 10-A).  velocity  A p p l i c a t i o n o f the T a y l o r Brace t o  S u b j e c t B showed changes i n the abnormal j o i n t s u r f a c e v e l o c i t y v a l u e s t o v a l u e s i n d i c a t i v e o f smooth, normal movement a t the surfaces  (Table 9-B).  articular  A p p l i c a t i o n o f the T a y l o r Brace t o S u b j e c t  r e s u l t e d i n an i n c r e a s e i n a l r e a d y abnormal v a l u e s degrees o f e x t e n s i o n  angle  (Table 10-B).  f o r the l a s t  T h i s i n c r e a s e may  few  be e x o l a i n e d  r o t a t i o n o f the t i b i a as a r e s u l t o f the screw-home mechanism o f knee.  D u r i n g t h e l a s t few degrees o f e x t e n s i o n ,  The  r o t a t i o n o f the. t i b i a a t t h i s p o i n t was  The  the  lateral  significant  enough t o produce i n c o r r e c t p r o j e c t i o n o f the i n s t a n t c e n t e r p o i n t s n o t on the m i d l i n e .  by  t i b i a l rotation  p r o j e c t s p o i n t s on a d i f f e r e n t p l a n e , n o t r e p r e s e n t i n g a t r u e roentgenogram.  C  from  u s e . o f p o i n t s on the m i d l i n e o f the  t i b i a l s h a f t r a t h e r than on the margins f o r the p r o j e c t i o n o f i n s t a n t c e n t e r would produce a more a c c u r a t e c a l c u l a t i o n .  the  Except f o r  t h i s impingement i n the l a s t few degrees o f e x t e n s i o n , S u b j e c t  C  demonstrates f r e e g l i d i n g a t the a r t i c u l a r s u r f a c e s . I t appears t h a t a p p l i c a t i o n o f the T a y l o r B r a c e t o the  unstable  knee produces changes i n abnormal j o i n t s u r f a c e v e l o c i t y angles w i t h i n the normal range.  With the e x c e p t i o n o f S u b j e c t C i n ' t h e  to last  few degrees o f e x t e n s i o n , t h e s e changes are i n d i c a t i v e o f r e l a t i v e l y f r e e g l i d i n g a t the a r t i c u l a r s u r f a c e s , throughout the monitored  range, increases i n abnormal values for Subject C can be explained by the presence of t i b i a l rotation and the use of points away from the midline causing miscalculation of the instant center for that particular segment.  Stress Analysis  Mechanical stresses were applied to the knee joint by means of a stress machine. knee.  Data was collected for each subject from the unstable  Roentgenograms were taken and the amount of medial and anterior  laxity determined for unbraced and braced conditions. The summary of results i s presented below for medial laxity (Table 11) and anterior laxity (Table 12).  A l l values for the braced  knee were recorded using the Taylor Brace.  TABLE 11 Medial Laxity*  Subject  Unbraced Unstressed  Unbraced Stressed  Braced Stressed  B  0.70  cms.  0.90  cms.  0.80  cms.  C  0.45  cms.  0.90  cms.  0.90  cms.  * a l l measurements of medial laxity were made in millimeters of distance between the sub-chondral bone of the medial femoral condyle and the sub-chondral bone of the medial t i b i a l condyle at a distance one centimeter from the medial margin of the proximal tibia.  88  TABLE 12 Anterior Laxity  Unbraced Unstressed  Subject  Unbraced Stressed  Braced Stressed  B  6.40 ens.  7.80 cms.  6.90 cms.  C  7.35 cms.  8.95 cms.  7.50 cms.  Tie overall effect of the Taylor Brace on anterior laxity can be seen in Table 13.  TABLE 13 Anterior Laxity Reduction Values  Subject  unbraced  braced  reduction  percentage  B  1.40 cms.  0.50 cms.  0.90 cms.  64  C  1.60 cms.  0.15 cms.  1.45 cms.  90  Results Table 11 (nedial laxity), in a.comparison of tlie unbraced, unstressed and unbraced, stressed columns shows a range of medial laxity for the two subjects of 0.20 centimeters to 0.45 centimeters.  Application of the  Taylor Brace to the unstable knee of.Subject S produced a reduction i n the  m e d i a l l a x i t y measurement o f 0.10  centimeters  ( f i f t y percent)  while  S u b j e c t C remained the same. T a b l e 12  ( a n t e r i o r l a x i t y ) , i n a comparison o f the  u n s t r e s s e d and unbraced,  unbraced,  s t r e s s e d columns sho/vs a range o f a n t e r i o r  l a x i t y f o r the two s u b j e c t s o f 1.40  c e n t i m e t e r s t o 1.60  centimeters.  A p p l i c a t i o n o f the T a y l o r Brace t o the u n s t a b l e knee produced  a  r e d u c t i o n i n t h e a n t e r i o r l a x i t y measurements o f b o t h s u b j e c t s ; o f S u b j e c t B by 0.50 by 1.45  centimeters  centimeters  ( s i x t y - f o u r percent)  ( n i n e t y p e r c e n t ) (Table  and o f S u b j e c t C  13).  Discussion  The t o 0.45 0.20  range o f m e d i a l l a x i t y f o r t h i s sample was  centimeters.  0.20  centimeters  S u b j e c t B w i t h a m e d i a l l a x i t y measurement o f  c e n t i m e t e r s i s below t h e v a l u e s r e p o r t e d by Kennedy and  (1971) and Roser e t a l (1971) f o r u n s t a b l e knees. m e d i a l l a x i t y measurement o f 0.45  c e n t i m e t e r s was  Subject  Fowler  C with a  within their  reported  range. Both s u b j e c t s t e s t e d w i t h the T a y l o r Brace under c o n d i t i o n s o f m e d i a l s t r e s s shaved minor o r n e g l i g i b l e changes i n the m e d i a l range.  These r e s u l t s are c o n s i s t e n t w i t h t h e s t r e s s a n a l y s i s  o f Roser e t a l  laxity findings  (1971) who r e p o r t e d r e d u c t i o n s o f 0.30 c e n t i m e t e r s and  i n c r e a s e s o f 0.10.  centimeters i n medial i n s t a b i l i t y  follaving  a p p l i c a t i o n o f the Palmer Knee Brace t o t h e u n s t a b l e knee. e x c e p t i o n o f S u b j e c t B who  shaved a decrease o f 0.10  With the  centimeters, i t  appears that the Taylor Brace is having l i t t l e or no effect on the nedial laxity of the unstable knee.^ The range of anterior laxity for this sample was 1.40 to 1.60 centimeters.  centimeters  These values are within the range rctx)rted by  Kennedy and Fowler (1971) for abnormal knees. Both subjects tested with the Taylor Brace under conditions of anterior stress displayed major decreases in the anterior laxity range (Table 13).  The values  demonstrated here are within those found by Poser et a l (1971) who reported reductions of 0.30 centimeters to 0.50 centimeters in anterior laxity following application of the Taylor Brace.  From the  results of both subjects, i t appears that the Taylor Brace i s producing a substantial decrease in the anterior laxity of the stressed knee.  Subjective Evaluation  Subjective evaluation of tlie Taylor Brace consisted of a verbal discussion with the subject following each session of physical activity, as well as an overall written assessement. Both the discussion and assessement were based on pre-determihed criteria. Subject A wore the Taylor Brace while narticinating in the following activities; rugby, cycling, volleyball, distance running, sprinting and weight l i f t i n g .  These are his comments:  "The most impressive thing about this brace i s the joint.  It  f i t s closely to tlie leg and can do anything the normal knee does. Even deep knee bends are easily done. The brace was easily applied  and  f i t snugly.  I t gave t h e Immediate i m p r e s s i o n  of stability.  There  was soma i n i t i a l i r r i t a t i o n a l o n g t h e f r o n t o f t h e t i b i a and b e h i n d the knee on t h e tendon o f b i c e p s ,  from r u b b i n g on t h e c u f f s .  The t h i g h  and c a l f c u f f s f i t w e l l b u t soon began t o g e t s l i p p e r y because o f sweat b u i l d i n g up i n s i d e .  With p r o l o n o u e d use t h e m e d i a l knee s t r a p  and c u f f s began t o s l i p down t h e l e g .  'During t h i s s l i p p a g e t h e j o i n t  s t i l l a r t i c u l a t e d w e l l b u t t h e c u f f s dug i n t o t h e t h i g h and s h i n making movement d i f f i c u l t .  There was n e v e r any c o n s t r i c t i o n o r  numbness i n t h e l e g t o hamper movement d e s p i t e p r o l o n g u e d use o f o v e r t h r e e hours on o c c a s i o n . one  The b r a c e was s o l i g h t t h a t a f t e r a w h i l e  f o r g o t t h a t t h e r e was a n y t h i n g  a t a l l on t h e knee."  S u b j e c t B wore t h e T a y l o r B r a c e w h i l e p a r t i c i p a t i n g i n t h e follaving activities;  squash, h a n d b a l l ,  volleyball,  s k i i n g , i n t e r v a l r u n n i n g and t r e e p l a n t i n g . "The  cycling, alpine  These a r e h i s comments:  a r t i c u l a t i o n o f t h e j o i n t was e x c e l l e n t .  The range o f  motion was i n no way hampered i n e i t h e r f l e x i o n o r e x t e n s i o n .  The  f i b e r g l a s s t h i g h and c a l f c u f f s had a tendency t o j a b i n t o t h e t h i g h a t some p o i n t s and p i n c h b e h i n d t h e knee and a l o n g The  the t i b i a l  snine.  s t i f f f i b e r g l a s s ( o f t i e t h i g h c u f f ) would n o t conform t o the  changing upper l e g muscles and tended t o s l i p down t h e l e g .  The  m e d i a l s u p p o r t s t r a p had a tendency t o s l i p down w i t h a c t i v e u s e . Because o f the d e s i g n ,  t h e p o p l i t e a l r e g i o n b e h i n d the knee was  never s e r i o u s l y occluded. was n o t n o t i c e a b l e  The weight o f t i e b r a c e  and d i d n o t hamper movement.  (.75 k i l o g r a m s )  A p p l i c a t i o n o f the  b r a c e was q u i c k and s i m p l e .  S u b j e c t C wore tlie T a y l o r Brace w h i l e p a r t i c i p a t i n g i n t h e f o l l o w i n g a c t i v i t i e s ; squash, rugby t r a i n i n g s e s s i o n s , slow jogging.  These a r e h i s ccmrients:  "When I f i r s t began t o use t h e b r a c e i t was a b i t  uncomfortable,  e s p e c i a l l y a t t h e back o f t h e knee ( l o n g head o f b i c e p s ) and on the s h i n .  A f t e r a w h i l e t h i s a l l went away.  The j o i n t moved w e l l .  There was n e v e r any r e s t r i c t i o n t o movement a t a l l .  There was a  d e f i n i t e movement o f tine brace down t h e l e g w i t h a c t i v e use and f r e q u e n t adjustements were n e c e s s a r y . l i g h t and i t n e v e r f e l t i n i t i a l wearing i n .  'The f i t was snug, t h e d e v i c e  r e s t r i c t i n g o r uncomfortable,  a f t e r the  You c o u l d even wear i t under t h e p a n t s  without  i t being noticeable.  Discussion  All  s u b j e c t s s u b j e c t i v e l y e v a l u a t e d f o l l o w i n g a c t i v e use o f t h e  T a y l o r 3 r a c e r e p o r t e d the f o l l o w i n g major p o i n t s : (a)  e x c e l l e n t j o i n t a r t i c u l a t i o n range even a f t e r o f t h e j o i n t from t h e knee a r e a .  displacement  (b)  i r r i t a t i o n from t h e f i b e r g l a s s c u f f s on t h e s k i n , e s p e c i a l l y i n t h e r e g i o n o f t h e l o n g head o f b i c e p s and a l o n g tlie a n t e r i o r s u r f a c e o f the t i b i a l s h a f t .  (c)  lack of.conformity o f the r i g i d f i b e r g l a s s t h i g h c u f f t o the changing q u a d r i c e p s muscle mass.  (d)  d e f i n i t e s l i p p a g e o f t h e t h i g h and c a l f c u f f s and m e d i a l s u p p o r t s t r a p down t h e l e g w i t h a c t i v e use.  93  (e)  ease o f a p p l i c a t i o n .  (f)  l i g h t weight,  (g)  comfort o f f i t w i t h no p i n c h i n g o r b i n d i n g a f t e r t h e i n i t i a l , wearing-in period.  (h)  no c o n s t r i c t i o n or numbness o f t h e l e g r e s u l t i n g i n r e s t r i c t i o n s t o movement.  not bulky.  CHAPTER V SUMMARY AND CONCLUSIONS  Summary  The  purpose o f t h i s study was  t o determine the e f f e c t o f tlie  T a y l o r Brace on t h e s t a b i l i t y and dynamic range o f motion o f the knee joint.  Tiie study was  under the testing,  d i v i d e d i n t o an a n a l y s i s o f the T a y l o r B r a c e  following experimental conditions; (b)  a n a l y s i s and  (a)  electrogoniometric  i n s t a n t c e n t e r o f r o t a t i o n c a l c u l a t i o n , (c) (d) s u b j e c t i v e  Electrogoniometric  stress  evaluation.  t e s t i n g consisted o f recordings  movement i n t h r e e m u t u a l l y p e r p e n d i c u l a r  o f knee  movement parameters o f  f l e x i o n - e x t e n s i o n , i n t e r n a l - e x t e r n a l r o t a t i o n and v a r u s - v a l g u s f o r the u n s t a b l e  knee.  T e s t i n g was  h a l l w a y f o r t y meters l o n g . e x c l u s i v e o f the f i r s t  and  conducted i n a l e v e l segment o f  E x p e r i m e n t a l runs c o n s i s t e d o f ten l a s t s t e p s . o f the run,  f o r unbraced  steps, and  braced conditions. I n s t a n t c e n t e r o f r o t a t i o n c a l c u l a t i o n was roentgenogram measurement o f the u n s t a b l e f i x e d t o the x - r a y t a b l e , the  t i b i a was  knee.  c a r r i e d out With the  manually moved.  through  femur f i r m l y Seven m e d i a l  roentgenograms were taken o f the knee from n i n e t y degrees o f f l e x i o n t o z e r o degrees o f f l e x i o n i n increments o f f i f t e e n t o twenty degrees.  The  i n s t a n t c e n t e r o f r o t a t i o n was c a l c u l a t e d f o r each x-ray f o r  unbraced and b r a c e d  conditions.  S t r e s s a n a l y s i s was c a r r i e d o u t on t h e u n s t a b l e mechanical s t r e s s apparatus. knee and r a d i o g r a p h i c recorded  knee u s i n g a  P e g u l a t e d f o r c e s were a p p l i e d t o t h e  changes i n the l a x i t y o f t h e knee  f o r unbraced and b r a c e d c o n d i t i o n s .  joint  M e d i a l and a n t e r i o r  l a x i t y measurements were made f o r unbraced, u n s t r e s s e d ;  unbraced,  s t r e s s e d ; and b r a c e d and s t r e s s e d c o n d i t i o n s . Subjective evaluation consisted o f verbal evaluation o f the brace function a f t e r periods  o f p h y s i c a l a c t i v i t y as w e l l as an  o v e r a l l w r i t t e n assessement a t t h e c o n c l u s i o n o f t h e s t u d y .  Both  p a r t s o f the s u b j e c t i v e e v a l u a t i o n were b a s e d on p r e - d e t e r m i n e d criteria.  S l e c t r o g o n i a n e t r i c r e s u l t s i n d i c a t e d a general  reduction  i n the  dynamic f l e x i o n - e x t e n s i o n , i n t e r n a l - e x t e r n a l r o t a t i o n and v a r u s - v a l g u s range o f the b r a c e d knee f o l l o w i n g a p p l i c a t i o n o f the T a y l o r Brace t o the walking subject.  The r e s t r a i n t on t h e dynamic f l e x i o n - e x t e n s i o n  range was c o n s i d e r e d  undesirable  b u t n o t s i g n i f i c a n t i n a l t e r i n g the  t o t a l g a i t pattern.  R e d u c t i o n o f i n t e r n a l - e x t e r n a l r o t a t i o n and  varus-valgus values,  however, were c o n s i d e r e d  i n the brace's a b i l i t y t o r e s t r a i n undesirable  t o be i m p o r t a n t f a c t o r s motions.  H i e movement  parameters o f t h e unbraced knee showed some f l u c t u a t i o n s i n t h e magnitude o f t h e range f o l l o w i n g a p p l i c a t i o n o f t h e T a y l o r Brace t o the c o n t r a - l a t e r a l knee.  These f l u c t u a t i o n s were minor i n t h e w a l k i n g  96  s u b j e c t w i t h a tendency t o i n c r e a s e i n magnitude as the speed o f ambulation  increased.  I n s t a n t c e n t e r o f r o t a t i o n c a l c u l a t i o n l o c a t e d the i n s t a n t c e n t e r o f r o t a t i o n pathway i n the r e g i o n o f the m e d i a l femoral c o n d y l e . was  no s e t p a t t e r n t o the pathway.  There  A p p l i c a t i o n o f the T a y l o r Brace  produced changes i n the pathway p a t t e r n and d i s t r i b u t i o n  (diameter)  but no t r e n d s were e v i d e n t . Abnormal j o i n t s u r f a c e v e l o c i t y angles  shaved d e f i n i t e a l t e r a t i o n s  t o normal v a l u e s , i n d i c a t i v e o f f r e e g l i d i n g a t the a r t i c u l a r s u r f a c e s , f o l l a v i n g a p p l i c a t i o n o f the T a y l o r Brace t o the u n s t a b l e  knee.  There were v e r y l i t t l e changes i n the m e d i a l l a x i t y measurements o f the u n s t a b l e knees f o l l a v i n g a p p l i c a t i o n o f the T a y l o r B r a c e t o the s t r e s s e d knee. subjects having  I t was  f e l t t h a t t h i s was  due  i n p a r t t o both  r e l a t i v e l y stable medial s t r u c t u r e s .  Anterior laxity  v a l u e s showed marked d e c r e a s e s by as much as n i n e t y p e r c e n t  in  one  s u b j e c t f o l l o w i n g b r a c i n g w i t h the T a y l o r B r a c e . S u b j e c t i v e e v a l u a t i o n showed e x c e l l e n t range and a r t i c u l a t i o n the T a y l o r Brace j o i n t w i t h v e r y l i t t l e r e s t r i c t i o n t o movement.  of  Subjects  found the b r a c e l i g h t w e i g h t , e a s y t o a p p l y , n o n - r e s t r i c t i n g and comfortable  t o wear.  Oi^servations were made t h a t the c u f f s and  medial  s t r a p d i d t e n d t o s l i p down the l e g w i t h a c t i v e use and t h a t t h e r e were sane i n i t i a l p r e s s u r e  areas a l o n g the a n t e r i o r s u r f a c e o f the  s h a f t and the tendon o f the l o n g head o f b i c e p s . the t h i g h c u f f was  The  r i g i d structure of;  not a c c o m o d a t i n g enough t o the changing  muscle mass d u r i n g a c t i v e use.  tibial  quadriceps  97  Conclusions  1.  The T a y l o r Brace has  a r e s t r a i n i n g e f f e c t on the dynamic  f l e x i o n - e x t e n s i o n range o f the b r a c e d knee t h a t i n c r e a s e s w i t h tlie speed o f ambulation.  T h i s r e s t r a i n i n g e f f e c t i s considered  u n d e s i r a b l e but n o t s i g n i f i c a n t i n a l t e r i n g tlie t o t a l g a i t p a t t e r n . 2.  The  T a y l o r Braos has  a r e s t r a i n i n g e f f e c t on the dynamic  i n t e m a l - e x t e m a l r o t a t i o n and v a r u s - v a l g u s  range o f t h e  braced  knee t h a t remains c o n s t a n t w i t h i n c r e a s e s i n the speed o f ambulation.  The  brace's  ability to restrain  motions i s c o n s i d e r e d an i m p o r t a n t 3.  those'-undesirable  factor.  A p p l i c a t i o n o f the T a y l o r Braoe t o the knee produces changes i n t h e movement p a t t e r n s o f the c o n t r a - l a t e r a l , unbraced knee.  4.  Changes i n the p a t t e r n and d i s p e r s i o n o f the i n s t a n t c e n t e r o f r o t a t i o n pathway o c c u r r s f o l l o w i n g b r a c i n g w i t h the T a y l o r Brace b u t no d e f i n i t e trends are  5.  There i s no r e c o r d a b l e  evident.  r e d u c t i o n i n m e d i a l l a x i t y measurements  f o l l o w i n g a p p l i c a t i o n o f the T a y l o r Brace t o t h e u n s t a b l e I t was  f e l t t h a t t h i s was  due  knee.  i n most p a r t t o b o t h s u b j e c t s  h a v i n g sound m e d i a l s t r u c t u r e s .  A n t e r i o r l a x i t y , however,  was  g r e a t l y r e d u c e d i n the u n s t a b l e knee f o l l o w i n g b r a c i n g . 6.  J o i n t a r t i c u l a t i o n range o f the T a y l o r Brace i s c o n s i d e r e d e x c e l l e n t w i t h comfortable  fit.  S l i p p a g e o f tlie b r a c e i s c o n s i d e r e d  to be a s i g n i f i c a n t problem as w e l l as the r i g i d n a t u r e fiberglass thigh cuff  t o be  construction.  of  the  98  CHAPTER VI RECENT DEVELOPMENTS AND SUGGESTIONS FOR FURTHER RESEARCH  New  Prototypes  S i n c e the development o f the f i r s t p r o t o t y p e  (Prototype I ) ,  c o n t i n u i n g r e s e a r c h has been c a r r i e d o u t on t h e T a y l o r B r a c e .  From  s u b j e c t i v e e v a l u a t i o n and c o n t i n u i n g s u b j e c t use, s e v e r a l r e f i n e m e n t s have been made i n t h e b r a c e d e s i g n t o enhance comfort and  fit.  F i g u r e 32. P r o t o t y p e I , T a y l o r Brace. Arrows i n d i c a t e s p l i t m e d i a l s t r a p and d i r e c t i o n o f a p p l i c a t i o n . Note t h e p o l y e s t e r r e s i n t h i g h and c a l f c u f f s .  99  A  B  D Ficnire 33. Tnylor Brace, rototvPe I I , (A t o E). Arrows i n d i c a t e s p l i t media] strap and d i r e c t i o n of a p p l i c a t i o n ( A ) . Note the replacement of "D" hooks by v e l c r o straps (I)) and tlie incorporation of s p i r a l webbinn t o fasten tlie brace to the l e g . P r i n t E shows the brace c u f f s w i t h the webbing removed. Into that the s i z e of the t h i g h c u f f has been reduced t o h a l f the previous s i z e and the rxjlynropylene m a t e r i a l -used i n cuff c o n s t r u c t i o n . p  100  ii  c  Figure 34. Taylor Brace, Prototype III, (A t o 12) . Arrows i n d i c a t e s i n g l e n e d i a l strap and d i r e c t i o n o f a n o l i c a t i o n . Note the medial s t r a o continues up the l o g t o form the webbed thigh fastener (A) , a n t e r i o r view. The metal j o i n t surface has been oadded w i t h f e l t f o r a t h l e t i c competition (13), l i t e r a l view. The p o p l i t e a l region of the knee i s s t i l l free (C), p o s t e r i o r view. P r i n t E shows the brace c u f f s w i t h the webbing removed. Jote the c a f f s i z e s are the sane as Prototype II and the d i f f e r e n t m a t e r i a l , ortholene, used i n c u f f c o n s t r i c t i o n .  101  102  Figure 36. J o i n t F i x a t i o n . (A) mechanical brace j o i n t positioned; (B) assembly base w i t h uncut geometry, too view; (C) assembly base, bottom view, snowing s u c t i o n cups; (D) assembly base, side view. To ensure proper n o s i t i o n of the mechanical brace j o i n t near the anatomical knee j o i n t and prevent slippage w i t h a c t i v e use, s u c t i o n cups have been applied w i t h s k i n cerent t o the s k i n at the knee.  103  Suggestions for Further Research  The following topics are suggested as continuing areas of research: 1.  Standardization and classification of tyoical stable and unstable knee patterns for varying rates of ambulation.  2.  Association of specific structural lesions of the knee with specific characteristics of gait.  3.  The use of cinematography in conjunction with  electrogoniometry  in the analysis of knee function under various conditions. 4.  Correlation of electromyography with electarogmiometry of leg function.  5.  Electaxjoniometric evaluation of specific sport activities, both indoor and outdoor, with relation to joint function.  6.  Investigation of the use of the Taylor Brace joint design in the cast-brace treatment of t i b i a l fractures.  104  BIBLIOGRAPHY  Cousins, S.J., A Parallelogram Chain Designed to Measure Human Joint Motion, Unpublished Masters Thesis, Department of Mechanical Engineering, University of British Columbia, Canada, 1975. Eriksson, E., Sports Injuries of the Knee Ligaments: Their Diagnosis, Treatment, Rehabilitation, and Prevention, Medicine and Science i n Sports, Vol. 8, No. 3: 133-144, 1976. Frankel, V.H., Burstein, A.H. and Brooks, D.B., Biomechanics of Internal Derangement of tlie Knee, Journal of Bone and Joint Surgery, Vol. 53-A, No. 5: 915-962, 1971. Gollnick, P.D. and Karpovich, P.V., Electrogoniometric Study of Locomotion and of Same Athletic Movements, The Research Quarterly, Vol. 35, No. 3: 357-369, 1962. Hallen, L.G., The "Screw-Home' Movement i n the Knee Joint, Acta Orthop. Scandia, 37: 97-106, 1966. 1  Helfet, A.J., Disorders of the Knee, J.B. Lippincott Company, Philadelphia, U.S.A., 1974. Helfet, A.J., Mechanism of Derangements of the Medial Semilunar Cartilage and their Management, Journal of Bone and Joint Surgery, 41-B: 319-336, May, 1959. Hughston, J.C., Andrews, J.R., Cross, M.J. and Moschi, A., Classification of Knee Ligament Instabilities Part I. The Medial Compartment and Cruciate Ligaments, Journal of Bone and Joint Surgery, 58-A, No. 2: 159-172, March, 1976. Hughston, J.C., Andrews, J.R., Cross, M.J. and Moschi, A., Classification of Knee Ligament Instabilities Part II. The Lateral Comnartment, Journal of Bone and Joint Surgery, 58-A, Mo. 2: 173-179,-March, 1976. Jesswein, P.O., Lower Extremity Orthotics III, VAPC Research, Bulletin of Prosthetics Research, pp. 261-262, F a l l , 1966. Johnston, R.C., Measurement of Hip Joint Motion During Walking: An Evaluation of Electrogoniometric Method, Journal of Bone and Joint Surgery, 51: 1083, 1969.  105  K a r p o v i c h , P.V., E l e c t r o g o n i c m e t r i e Study o f J o i n t s , U.S. Armed F o r c e s M e d i c a l J o u r n a l , 11: 424, 1960. Kennedy, J . C . and Fowler, P . J . , M e d i a l and A n t e r i o r I n s t i b i l i t y o f t h e Knee, J o u r n a l o f Bone and J o i n t S u r g e r y , V o l .  53-A, Mo. 7: 1257-1270, 1971. Kennedy, J . C , Weinberg, H.W. and W i l s o n , A.S., The Anatomy and F u n c t i o n o f t h e A n t e r i o r C r u c i a t e Ligament, J o u r n a l o f Bone and J o i n t S u r g e r y , V o l . 56-A, No. 2: 223-235,  1974. Kettlekamp, D.B., Johnson, R.J., Smidt, G.L., Chao, E.Y.S. and Walker, M., An E l e c t r o g o n i o m e t r i c Study o f Knee Motion i n Normal G a i t , J o u r n a l o f Bone and J o i n t S u r g e r y , 52: 775-790,  1970.  1  :  '  Lamoreux, L.W., K i n e m a t i c Measurements i n t h e Study o f Human Walking, B u l l e t i n o f P r o s t h e t i c s Research, pp. 3-81, S p r i n q ,  1971.  L a u b e n t h a l , K.N., Smidt, G.L. and Kettlekamp, D.B., A Q u a n t i t a t i v e A n a l y s i s o f Knee M o t i o n D u r i n g A c t i v i t i e s o f D a i l y L i v i n g , P h y s i c a l Therapy J o u r n a l , V o l . 52, No. 1: 34-42^ January, 1972. Lehmann, J . F . , Warren, C G . and DeLateur, B . J . , A B.iomechanical E v a l u a t i o n o f Knee S t a b i l i t y i n Below-Knee B r a c e s , A r c h i v e s o f P h y s i c a l M e d i c i n e and R e h a b i l i t a t i o n ,  pp. 688-695, December, 1970. Meek, R.N., Martens, M. and Temets, D., C o r r e l a t i o n o f I n s t a n t C e n t e r Displacement and I n t e r n a l Derangement o f the Knee, Research Paper, u n p u b l i s h e d , Vancouver G e n e r a l H o s p i t a l , Department o f O r t h o p a e d i c s , Vancouver, Canada.  !  Noonan, R.C., and Cooke, C , A P i c t o r a l and D e s c r i p t i v e T a p i n g Manual F o r A t h l e t i c I n j u r y Management, g o i n g t o o r e s s , 1977. O'Donoghue,  D.H., S u r g i c a l Treatment o f F r e s h I n j u r i e s t o t h e Major Ligaments o f t h e Knee, J o u r n a l o f Bone and J o i n t  Surgery, V o l . 32-A, No. 2: 721-738, 1950. O'Donoghue,  D.H., R e c o n s t r u c t i o n f o r M e d i a l I n s t a b i l i t y o f t h e Knee, J o u r n a l o f Bone and J o i n t S u r g e r y , V o l . 55-A: 941-55,  1973.  Roser, L.A., M i l l e r , S . J and Clawson, D.K.,. E f f e c t s o f T a p i n g and B r a c i n g on t h e U n s t a b l e Knee, Northwest M e d i c i n e : pp. 544-546, August, 1971, R o z i n , R., Robin, G . C , Magora, A., Gonen, B. and S a l t i e l , J . , I n v e s t i g a t i o n o f G a i t : I I I A n a l y s i s o f Lower  106  Extremities Braced with a Standard Belav-Knee Appliance, Electromyography and C l i n i c a l Neurophysiology, Vol. 12, 433-440, 1972. Rouleaux, F., The Kinematics of Machinery; Outlines of A Theory of Machines, Translated and Edited by A.B. Kennedy, Macmillan and Company, London, England, 1876. Slocum, D.B., Larson, R.L. and James, S.L., Pes Anserinus Transplant: Impressions After a Decade of Experience, Journal of Sports Medicine, 2: 123-136, 1974. Slocum, D.B., Larson, R.L. and James, S.L., Late Reconstruction of Ligamentous Injuries of the Medial Coripartment of the Knee, Clinical Orthopaedics, 48: 23-55, 1975. Smidt, G.L., Biomechanical Analysis of Knee Flexion and Extension, Journal of Biomechanics, Vol. 6, pp. 79-92, 1973. Tipton, CM. and Karpovich, P.V., C l i n i c a l Electrogonicmetry, Journal of the Association for Physical and Mental Retardation, Vol. 18, No. 4, pp.90-109, July-August, . 1964. Tipton, CM. and Karpovich, P.V., Electrogonionetric Reoprds of Knee and Ankle Movements i n Pathologic Gaits, Archives of Physical Medicine and Rehabilitation: 267-272, March, 1965. Wang, C.J., Rotatory Laxity of the Human Knee Joint, Journal of Bone and Joint Surgery, 56: 161-70, January, 1974. Wolf, B., The Effects of Flexion and Rotation on the Length Patterns of the Ligaments of the Knee, Biomechanics, Vol. 6: 587-596, 1973.  APPENDIX A  KNEE AXES OF ROTATION  108  APPENDIX A  Knee Axes o f R o t a t i o n  •  FLEXION ! ROT, -  INTERNAL-EXTERNAL ROTATION -AXIS  VARUS-VALGUS ROTATION AXIS  internal  rotation  external  rotation  APPENDIX B  SUBJECT CASE HISTORIES  110  APPENDIX B  SUBJECT CASE HISTOPIES  Subject B Weight: 70.4 Kg. Age: 24 years  Occupation: Student  Height: 140.8 arts.  This young man received a twisting injury to the medial aspect of the l e f t knee during the winter of 1970.  During a slalom ski  race, the t i p of his l e f t ski caught a pole and forcefully externally rotated.  The l e f t leg became abducted and pressure of the f a l l was  directed on the medial aspect of the l e f t knee. He remembers a pain on the medial aspect but got up and continued the race. Tenderness and swelling persisted and he consulted an orthopaedic surgeon. Clinical examination reveals a relatively lean and muscular young man of stated age with good quadriceps bulk and tone.  There  is demonstrable medial laxity i n both l e f t and right knees on aoDlicatlon of valgus stress.  There i s marked antero-posterior  laxity with internal t i b i a l rotation on examination with the anterior drawer test. Since the time of the i n i t i a l injury, the subject has maintained an active l i f e .  He continues to ski, run, play handball and squash.  He suffers repeated bouts of "knee collapse", pain and swelling i f he attemps to internally rotate with the hip on a flexed and weightbearing knee. He appears to suffer from the "pivot-shift'' phenomenon. Tha subject has never been a candidate for surgery.  Subject C Weight Age: 29 years  Occupation: Businessman  104.5 Kg.  Height: 162.8 cms.  This man has had a history of knee injury from the age of 10 years.  He reports collapsing on the knee of the right lea repeatedly  while playing as a youngster.  As he grew older, lie developed the  quadriceps musculature and was able, with few problems, to actively engage in competitive rugby.  For several years he continued,  reaching national caliber and then retiring.  After a vear's absence,  he returned to the rugby scene suffering a "knee collaose" during a practice.  Swelling resulted and, he consulted an orthopaedic surgeon.  Clinical examination revealed a loose body i n the medial aspect of the knee which was .confirmed by x-ray.  Surgery was performed on  the right knee in 1973 and the bone chip removed. He resumed his activity after rehabilitation playing rugby, handball and squash. After another lay-off of a year, he resumed competitive rugby. Another injury to the right knee resulted in swelling and pain on the medial aspect of the knee.  The excess fluid was drained and  the diagnosis of a strain of the medial collateral ligament was made. Another collapse of the knee resulted in arthroscopy in 1976 where incisions were made on the medial and lateral aspects of the right knee. No involvement of the menisci was found but the diagnosis of osteochondritis dessecans was made. The subject continues to be active, has lost some weight (10 kilos).and s t i l l suffers from knee collapse, pain and swelling.  There i s no ctemonst rable anterior or  medial laxity on c l i n i c a l exaiTunation.  r  112  APPENDIX C  2x2  CDLLAPBIBLE PARALLELOCIRAM CHAIN ELEGrROGQliaiETER  113 APPENDIX C 2x2  COLLAPSIBLE PAPALLELOGPAM CHAIN EIECTROGONIOME'rER  Figure 37. Parallelogram chain linkages shewing (A) application on leg with brass brackets, metal wire thigh and calf frames and potentiometer cluster, (B) enlarged view of 2 x 2 narallelogram chain; arrows indicate longitudinal direction of chain scissoring allowing perpendicular rotations to pass through tlie chain unchanged while absorbing unwanted translations, and (C) enlarged section of parallelogram chain shewing hinge design. Parallelogram chain is constructed of polyurethane and is cast vacu-moulded.  114  APPENDIX D  ELECTr«m«iaETRIC TESTING DATA SHEET  115 Page 1  APPENDIX D  E l e c t r o g o n i o m e t r i c T e s t i n a Data Sheet*  Test  Patient:  Date:  T e s t Sequence Time L i n e s : end  start A.  Motions measured  li.  Activities  C.  A i d s used  D.  C h a r t sneed  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * A.  Code Boxes f o r M o t i o n s :  1. v/v  HIP L R  KNEE L R  EX/ROT FLEX  J/  E  2. v/v  HIP L R  KNEE L R  I/E F/E STANDING ZEROS h ••  HIP L R  F/E  ANKLE, L R DIR'N  VAL  I/E F/E  V/V  (shade i n boxes)  KNEE L R  ANKLE L R DIR'N VAL EX/ROT FLEX STANDING ZEROS  v a l u e s are f o r F/E, I/E R o t a t i o n , V/V  4.  ANKLE DIR'N L R VAL EX/ROT FLEX S T A N D S G ZEROS  HIP L R  V/V J/E . F/E h l e f t to right  KNEE L R  ANKLE L R DIR'N VAL EX/ROT FLEX i  STANDING ZEROS on oaqe  * r e v i s e d from an o r i g i n a l v e r s i o n by Steven C o u s i n s , Canadian and Rheumatism S o c i e t y , Vancouver, B r i t i s h Columbia.  Arthritis  Page 2 116 b.  C.  Code f o r A c t i v i t i e s : 1.  Slow l e v e l walk  2.  Comfortable l e v e l walk  3.  Fast l e v e l walk  4.  Slav l e v e l run  5.  Comfortable l e v e l run  Code f o r Aids: 1.  None  Braces - Knee Taylor Brace ( l a t e r a l iron) Other Experimental Brace(s)  Left L.Varus L. Valgus  Bilateral Varus Valgus  Right R.Varus R.Valqus  2  3  4  5  6  7  8  9  10  11  12  13  Riqht Knee L e f t Knee Int.Rot'n stop Ext.Rot'n stoo Int.Rot'n stoo Ext.Rot'n stoo Lennox-Hill 3raca  D.  14  Code f o r Chart Speeds inm/min  mm/sec  50  1  5  125  2  6  500  3  7  1250  4  8  15  16  17  117 Paae 3  Test  Results  Patient:  T e s t Date:  Code Boxes** Knee F/E  Dynamic Range of Motion  R L  I/E/R Dynamic Range of Motion  R  Dynamic  R  Range of Motion  L  V/V  L  ** Use codes f o r A c t i v i t i e s and A i d s  from Page 1,  eg.,  1/1  = slow, l e v e l walk, no a i d s .  1/5  = s l o w , l e v e l walk, T a y l o r B r a c e , r i g h t knee, r i g h t  valgus.  118  APPENDIX E  INSTANT CENTER OF ROTATION CALCULATION  APPENDIX E  F i g u r e 38. Instant center of r o t a t i o n c a l c u l a t i o n shaving (B) s u c c e s s i v e p o s i t i o n s o f p o i n t s f o r p l o t t i n g c e n t e r f o r knee motion from f l e x i o n t o e x t e n s i o n ; (E) c a l c u l a t i o n o f i n s t a n t c e n t e r from p e r p e n d i c u l a r b i s e c t o r s o f p o i n t s , and (M) i n s t a n t c e n t e r o f r o t a t i o n pathway on m e d i a l c o n d y l e o f femur.  119  

Cite

Citation Scheme:

    

Usage Statistics

Country Views Downloads
United States 7 0
Japan 4 0
China 2 0
Poland 1 0
Russia 1 0
Hong Kong 1 0
City Views Downloads
Tokyo 4 0
Ashburn 3 0
Unknown 2 0
Mountain View 2 0
Beijing 2 0
Central District 1 0
Sunnyvale 1 0
Saint Petersburg 1 0

{[{ mDataHeader[type] }]} {[{ month[type] }]} {[{ tData[type] }]}
Download Stats

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0077338/manifest

Comment

Related Items