Realignment of the knee, or distal femoral osteotomy, can be used alone as treatment for lateral compartment osteoarthritis or to correct alignment in conjunction with other cartilage repair procedures. In order to determine if a distal femoral ostetomy is an appropriate procedure for the surgeon to obtain a few different imaging studies. These studies will include regular Xrays, bone length films to determine alignment, and possibly an MRI. Using these studies the surgeon will be able to calculate the angle he will need to use in order to correct the malalingment. Distal femoral osteotomies are often used to treat arthritis in active patients who are still too young to have a joint replacement or whose activity level is such that they would damage or wear out an artificial joint prematurely.