Nearly 500,000 knee replacements are performed every year in the United States to treat severe knee osteoarthritis, the loss of the cushiony cartilage padding the knee. Although some people think they have to "baby" the knee and leg after surgery, the opposite is true. A study published in the February 2009 issue of Arthritis Care & Research demonstrated that doing exercises to strengthen the quadriceps, specifically, is critical to recovery and return to function. "Certainly, its important to work your quadriceps postoperatively," says Gary Calabrese, PT, director of Sports Health and Orthopaedic Rehabilitation at Cleveland Clinic. "But its also important to restore the balance among all the muscles above and below the knee." This means that while youre strengthening your quads, youll also need to strengthen the hamstrings (back of the thigh), your calves, and the muscles around the ankles that allow you to flex your feet.