Flexion and extension gap balancing in revision total knee arthroplasty

Abstract

The principles in a revision total knee arthroplasty are similar to that of primary total knee arthroplasty (TKA), however, during a revision, it is imperative to achieve a balanced, stable knee with optimal function by restoration of the joint line and soft tissue balancing. The technique regarding the basic principles for gap balancing is based on 3 points: (1) distal femoral resection or augmentation affects only the extension gap, (2) femoral downsizing affects only the flexion gap, and (3) proximal tibial resection or increasing tibial insert thickness affects both the flexion and extension gaps symmetrically. Consistently good results can be achieved if a sequential approach is employed, beginning with revealing the underlying mechanism of failure. Also, evaluating the patient clinically before and while under anesthesia prior to the operation in combination with the intra-operative findings enables the surgeon to identify any imbalances in soft tissues and correct it as well as choosing the appropriate prosthesis. In this article, a review of the sequential steps to balancing the soft tissues and restoring the height of the joint line in a revision TKA is presented.