Studies show this is typical, but it's not normal. Many adults have only half the muscle and leg power they need to be active and fully functioning.

Research shows this weakness is probably present long before the joint is replaced. It's likely the result of months and years of adapting to the pain and limits from arthritis.

A standard exercise program after total knee replacement (TKR) may not be enough. Scientists are looking for the best mix of exercises and activities to fully restore the entire limb after TKR.