High Tibial Osteotomy: Review of Techniques and Biomechanics

Abstract

High tibial osteotomy becomes increasingly important in the treatment of cartilage damage or osteoarthritis of the medial compartment with concurrent varus deformity. HTO produces a postoperative valgus limb alignment with shifting the load-bearing axis of the lower limb laterally. However, maximizing procedural success and postoperative knee function still possess many difficulties. The key to improve the postoperative satisfaction and long-term survival is the understanding of the vital biomechanics of HTO in essence. This review article discussed the alignment principles, surgical technique, and fixation plate of HTO as well as the postoperative gait, musculoskeletal dynamics, and contact mechanics of the knee joint. We aimed to highlight the recent findings and progresses on the biomechanics of HTO. The biomechanical studies on HTO are still insufficient in the areas of gait analysis, joint kinematics, and joint contact mechanics. Combining musculoskeletal dynamics modelling and finite element analysis will help comprehensively understand in vivo patient-specific biomechanics after HTO.

Figure 1

Flow chart.

Figure 2

Radiographic lower limb alignment assessment. The mechanical axis of the limb (red line) is defined by a line from the center of the femoral head to the medial tibial spine and a line from the medial tibial spine to the center of the ankle. The weight-bearing line (also represented by the red line, as this knee has normal alignment of 0°) is defined by a line from the center of the femoral head to the center of the ankle joint. The anatomic axis of the limb (black line) is defined by mid-diaphyseal lines in the femur and tibia. In a varus knee, the weight-bearing axis passes medial to the medial tibial spine. In a neutral knee, the weight-bearing axis passes through the medial tibial spine. In a valgus knee, the weight-bearing axis passes lateral to the medial tibial spine [32].

Figure 3

Schematic of open-wedge HTO (a) and closed-wedge HTO (b) of a knee with varus deformity.