UBC Theses and Dissertations
The effects of familial hypercholesterolemia on Achilles tendon biomechanics : a cross-sectional study Squier, Kip
Familial hypercholesterolemia (FH), a common genetic metabolic disorder characterized by high cholesterol levels, is involved in the development of atherosclerosis and other preventable diseases. FH can also cause tendinous abnormalities, such as thickening and xanthoma (tendon lipid accumulation) in the Achilles and extensor tendons, which may impact and impede tendon biomechanics. There is evidence that high cholesterol may lead to tendon injury or pain, but tendon biomechanics has received little investigation in people with FH. The objective of this study was to investigate how FH can affect Achilles tendon biomechanics, in vivo. 16 FH participants were recruited locally from the British Columbia FH Registry database. 16 control participants were recruited from purposeful convenience sampling. All participants completed preferred pace walking trials, shod, on a fully instrumented treadmill to collect gait impact data. Achilles tendon (AT) biomechanical data was obtained according to previously published methodology; simultaneously, lower limb kinematics, and muscle-tendon junction displacement were measured by motion capture and b-mode ultrasound imaging, respectively. AT strain, stiffness and hysteresis were calculated using a custom built Matlab program. AT biomechanical outcomes were assessed for statistical differences using MANCOVA. 16 FH participants (10 males, 6 females, 37±6 years, BMI of 28±4 kg/m²) and 16 control participants (10 males, 6 females, 36±7 years, BMI of 27±3 kg/m2) were recruited. FH participants displayed similar AT peak strain (FH: 5.07±0.9%, Controls: 4.95±0.9%; p=0.790), lower stiffness (FH: 87±20 N/mm, Controls: 111±18 N/mm; p=0.001), and higher hysteresis (FH: 56±17%, Controls: of 35±12%; p=0.007), when compared to controls. To the best of our knowledge, this is the first study that evaluates the impact of FH on AT biomechanics, in vivo. The results of the current study provide evidence that cholesterol accumulation can negatively affect AT biomechanics and potentially increase the chance of injury. The findings of this study will be of interest to clinicians, and people with FH and high cholesterol.
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