Summary

Augmentation of the patellar tendon with autologous hamstring tendon graft is a simple and effective way to achieve a strong extensor mechanism function

Abstract

Introduction

An intact Extensor Mechanism is vital for a successful rehabilitation and functional outcome following a Total Knee replacement (TKR). In patients requiring revision knee replacement surgery, the extensor mechanism may be compromised either due to scarring from previous surgery or during intraoperative release. Not infrequently, the Patellar tendon is either disrupted or very tenuous being reduced to a thin membranous structure causing significant extensor lag and instability while walking. Various techniques have been described in the literature to reconstruct the extensor mechanism in non-prosthetic knee joint. We share our experience in using Hamstrings tendon auto graft in augmenting patellar tendon in patients undergoing revision total knee replacement. PATIENTS AND METHODS: 10 patients underwent knee replacement with revision prosthesis and augmentation of patella tendon with hamstrings tendon autograft at our center between Jan 2014 and December 2015. 5 of these patients had infected loosening of TKR, 3 patients had aseptic loosening and 2 other patients had post traumatic deformity of knee with shortening following distal femur fracture. All these patients had significant extensor lag .Two patients were wheelchair bound. RESULT: All patients achieved satisfactory functional outcome following Revision TKR. Mean range of movement was 95 degrees and mean extensor lag was 4.3 degree. The mean knee society scores for pain and function improved significantly ( p<0.01) and the average Hospital for speciality surgery score was 90 points. There were 2 cases of superficial wound dehiscence which healed with regular dressing. There were no cases of deep infection or thromboembolic events. CONCLUSION: In patients with deficient extensor mechanism needing revison TKR, augmentation of the patellar tendon with autologous hamstring tendon graft is a simple and effective way to achieve a strong extensor mechanism function. Even in cases where the tendon is intact but structurally compromised due to multiple previous surgeries, we recommend extensor tendon augmentation to achieve improved functional outcome following revision total knee replacement.