The Effect of Therapeutic Exercise on Cartilage Morphology and Physical Function for Individuals at High Risk of Knee Osteoarthritis

Inclusion Criteria: 1. Are between 35 and 55 years of age. 2. Have a symptomatic degenerative medial meniscus tear as evidenced by: * Presence of medial knee pain. * Medial joint line tenderness. * Pain and limited motion when attempting to perform a full squat and * Increased intra-meniscal signal on at least 2 consecutive MRI slices and 3. Have clearance from their personal physician to participate in an exercise program. Exclusion Criteria: 1. Radiographic evidence of OA (K-L grade 2 or above). 2. A repairable meniscus injury (longitudinal tear in the outer 1/3 of the meniscus). 3. A meniscus injury that requires meniscectomy (locked knee). 4. Prior or current ligament injury or surgery of the involved knee. 5. Prior or current injury or surgery to contra-lateral knee. 6. Pathological ligamentous laxity upon examination of the knee 7. An inflammatory arthritic condition or 8. Any injury or condition involving the lower extremities that affects their ability to walk. Because participation in this study requires undergoing MRI, subjects will be excluded if they: 1. If female, pregnant at the time of enrollment. 2. Had prior surgery for an aneurysm; any medical illness that may interfere with the patient's general fitness or exercise capability. 3. Had any contraindication with MRI. 4. Had surgery within the past two months. 5. Have a cardiac pacemaker.