Limb malalignment results in an imbalance of force transmission to the knee joint. A varus deformity is most common, because osteoarthritis typically involves the medial compartment. Articular cartilage, bone, and medial meniscus loss combined with lateral collateral ligament stretching cause an increased tibial condylar-plateau angle. The resultant load concentration at the medial portion of the joint contributes to arthritis pain.

A valgus-producing tibial osteotomy can redistribute the weight-bearing forces, lessen the medial compartment load, and reduce the varus knee moment. The goals of this procedure are to relieve pain, buy time before an arthroplasty is necessary, and decrease forces on ligament, meniscus, and osteochondral grafts. Unicompartment or total knee arthroplasty have supplanted realignment osteotomy as a primary treatment for many middle-aged patients with gonarthrosis. However, the indications for an osteotomy have actually broadened to include younger patients or athletes with ligament deficiencies, chondral defects, absent menisci, or post-traumatic degenerative arthritis. An osteotomy should also be performed in combination with ligament reconstruction, articular cartilage regeneration, or meniscal transplantation in a knee with associated limb malalignment.

The lateral closing-wedge osteotomy of the proximal tibia was popularized by Coventry in the 1960s (1,2). Appropriate patient selection and sufficient postoperative correction have been correlated with a 90% success rate at more than 10 years after surgery (3, 4, 5). Worsening of results is caused by recurrent pain, arthritis progression, and occasionally, recurrence of varus deformity (6). In recent years, a medial opening-wedge osteotomy of the proximal tibia has gained popularity as new instrumentation and implants have become available (7, 8, 9).

The advantages of the opening-wedge technique include:

Disadvantages of the opening-wedge technique include:

A valgus-producing osteotomy of the proximal tibia is primarily indicated for pain relief in patients with medial compartment arthritis and/or mechanical axis correction as an adjunct to other reconstructive knee procedures. Patients should have pain and tenderness localized to the medial joint line, less than 10 degrees of terminal knee extension loss, and greater than 90 degrees of knee flexion. Osteotomy can be performed in patients with:

Osteotomy should be avoided in patients with (11):

Gait observation and physical examination of the knee will identify a lateral thrust and pathologic collateral ligament laxity that may not be apparent on standing radiographs. The desired angle of correction is determined by static analysis of full-length standing roentgenograms (51 × 14 inches). The mechanical axis of the limb is the angle formed between a line drawn from the hip center to the knee center (femoral mechanical axis) and a line drawn from the knee center to the ankle center (tibial mechanical axis). The normal mechanical axis is approximately 1.2 degrees of varus (12). A valgus-producing proximal tibial osteotomy performed for medial compartment arthritis typically overcorrects the mechanical axis to 3 to 5 degrees of valgus. The Weight-Bearing Line Method is a simple and reproducible technique for determining the desired coronal plane correction angle (Fig. 27-1) (13).