Regional Cartilage Thinning Occurs First in the Walking Weight Bearing Regions of the Femur in Medial Compartment Knee Osteoarthritis

Osteoarthritis (OA) of the knee affects an estimated 20–40% of individuals over the age of 65 [1], and is nearly 10 times more common in the medial compartment than the lateral compartment [2]. Plain radiography measurements using the Kellgren and Lawrence (KL) scale have been the gold standard for diagnosis of knee osteoarthritis [3]. However, for new treatment interventions for medial compartment knee OA such as load modifying footwear, it would be important to know if the disease-related cartilage loss in the medial compartment occurs initially and predominantly in regions that are weight bearing during walking. Because walking results in highest weight bearing occurring in the anterior and middle regions of the femoral condyle and the anterior region of the tibial plateau, seeing a pattern of thinning in these areas would suggest that walking is an important activity for understanding both the cause and treatment of osteoarthritis.