How Muscle and Tendon Properties Contribute to Functional Change Prior to and Following Knee Replacement

It is unknown how progressive physiological change in muscle and tendon contributes to loss of functional ability in patients undergoing total knee replacement between referral to surgery, and during post-surgery recovery. This study will use ultrasound and neurophysiological measures to evaluate progressive alterations of tissue to understand functional decline in men and women prior to and following knee replacement surgery. A group of healthy controls not undergoing knee replacement will also be studied to contrast changes in the patient group to normal changes over time. It is hypothesized that from the point of referral to surgery, patients will exhibit reductions in muscle and tendon size (atrophy) and reflex excitability that will be greater in the surgical compared with non-surgical leg, and these changes will precede observable losses in functional measures and strength. Secondly, it is hypothesized that following total knee replacement, muscle and tendon size, reflex activity, strength and functional measures will increase to a level below the pre-surgery values.