Last updated: 02/17/2009

Severe or chronic pain and/or knee instability brings the patient to an orthopedic physician. From there, the decision is made for surgery or for rehabilitation. Patients will undergo an examination and history with their physician. Once rehabilitation...

or other treatments are ruled out and surgery is indicated, the physician must assess for three factors: pain, instability, and knee alignment. Osteotomy is indicated if malalignment is a factor. Debridement, or the shaving of cartilage on the articulate femur or tibia, can usually resolve pain with instability problems. It must be determined whether the instability is related to malalignment and not to other sources such as ACL injury. Since the goal of osteotomy is to shift weight from a symptomatic cartilage to an unsymptomatic area to relieve both an instability and pain due to excessive contact, alignment of the knee is assessed for pressure distribution along the mechanical axis and the loading axis. This requires an analysis of gait pattern, range of motion, localized areas of pain, and neurological factors, as well as other technical tests for anterior instability. A diagnostic arthroscopy—examination of the knee joint with a long tube attached to a video camera—is usually indicated before all knee osteotomies. Cartilage surfaces are examined for degenerative or late-stage arthritis. Magnetic resonance imaging (MRI) is useful in evaluating any intra-articular pathology such as bone chips, padding tears, or injuries to ligaments.