Fixation stability and new surgical concepts of osteotomies around the knee

Abstract

Osteotomy around the knee, in order to re-align its mechanical axis, thereby unloading certain degenerated and painful regions of the joint, was once a well-established technique in the treatment of uni-compartmental osteoarthritis of the knee. To a large extent this was because of a lack of other treatment options. In more recent years, osteotomy around the knee has increasingly been replaced by total knee arthroplasty (TKA), which has proven to be a very successful and reliable procedure. Compared to joint replacement, osteotomy is considered a technically more demanding procedure with a less predictable outcome, and associated with significant complications.

In the past, the surgical techniques for osteotomies were either dependent on fairly unstable methods of fixation, e.g. staples or just a plaster cast, or on difficult to use implants, i.e. the AO angled blade plate, making the surgical procedure more complex. As a result of new fixation techniques that were initially developed in fracture surgery, new options became available for the fixation of osteotomies. Specifically designed fixation plates based on the locking-compression-plate (LCP) concept, using so-called angle stable locking bolts developed in fracture surgery, hypothetically providing superior initial stability, have been adapted for use in osteotomy surgery. New opening-wedge tibia and femur osteotomy techniques have since been introduced, further decreasing the surgical difficulty of these procedures and increasing its predictability. All these factors have led to a renewed interest in osteotomy around the knee.

Depending on the anatomical location of the deformity to be corrected, osteotomies around the knee can be divided in ones below the joint line: High Tibial Osteotomy (HTO), and osteotomies above the joint line: Supra-Condylar Femoral Osteotomy (SCO). The goal in either is to change the load distribution across the knee joint from the diseased part to the relatively healthy lateral part to reduce pain, slow the degenerative process and postpone the placement of an artificial joint.

In this thesis, in a number of studies, new surgical techniques for corrective distal femur and proximal tibial osteotomy are introduced and a scientific basis for choosing between the various surgical options and post-operative rehabilitation protocols is provided. Opening and closing wedge proximal tibia osteotomies and post-operative early and full weight bearing are compared in two clinical studies. Distal femoral osteotomy techniques and fixation methods are compared; a newly developed so-called biplane technique and a novel less-invasive approach to the distal medial part of the femur are introduced and compared to standard techniques. The primary stability of the osteotomy construct after surgery is addressed and guidelines for surgical treatment and rehabilitation are offered.