Opening-wedge high tibial osteotomy

Introduction

In the setting of coronal plane malalignment, the mechanical axis deviates medial or lateral to the approximate mid-point of the tibial plateau and results in unevenly distributed forces causing overload into either the medial compartment (varus malalignment) or lateral compartment (valgus malalignment). Chronic uneven distribution of force can then result in early degenerative changes of the affected knee compartment. Surgical treatment of osteoarthritis can be accomplished by various techniques, depending on patient factors and the degree of arthritis. When the arthritic changes are confined to one compartment, an osteotomy provides a potential solution for both offloading the affected compartment while also addressing the underlying causative malalignment, correcting the abnormal joint biomechanics. Osteotomy can be accomplished at both the distal femur and the proximal tibia to address these issues. However, the high tibial osteotomy (HTO) is performed more commonly for medial compartment disease. Less common surgical options available to modify the coronal and sagittal alignment of the proximal tibia include the dome osteotomy or gradual correction with an external fixator. These operations both offer the ability to correct large deformities that are not easily correctable by either the opening or closing wedge single-stage techniques.

High tibial osteotomies have been used for over a half century in orthopedic surgery to address cartilage injuries and malalignment in the injured or degenerative knee. The first description in the English scientific literature of using “upper tibial osteotomy” to manage unicompartmental degenerative arthritis of the knee was attributed to Jackson and Waugh. In its early description, they described the evolution in technique of applying the early principles of Blounts work on proximal femoral osteotomies for changes at the hip joint and extrapolating this to the treatment of unicompartmental injuries of the knee. The clinical results of Jackson and Waughs patients showed considerable relief of their pain with their intervention.

Since this initial description, significant advances have been made in the treatment of degenerative compartment changes of the knee as well as focal chondral defects. The use of tibial osteotomies for treatment of medial compartment osteoarthritis in patients greater than age 55 to 65 years has decreased with the advent of unicompartmental knee arthroplasty. However, the role of HTO remains a valuable surgical technique for patients not only in this age population but also the younger active patient with medial compartment cartilage defects or degenerative changes, who wish to remain active and avoid or delay an arthroplasty procedure. ^, This chapter focuses on the treatment of medial compartment disease with an unloading, realigning opening wedge osteotomy of the proximal tibia.