Patellar instability in a prothesis knee: MPFL plasty using hamstring tendon

Abstract

Introduction: instability of the patella remains a frequent cause of failure following arthroplasty; requires treatment and a precise radiological assessment. Several therapeutic options are possible, including ligamentoplasty of the medial patellofemoral ligament, which is increasingly used, thus proving its effectiveness. Observation: we report the case of an octogenarian patient with gonarthrosis of the knee that has been progressing for several years. He benefited from a knee prosthesis, the consequences of which were marked by a progressive lateral tilt of the patella. Technique: installed in the supine position with resumption of the old approach, sampling of the half tendon was carried out with preparation of the graft on the table. The careful release of the joint and preparation of the graft placement sites then the approach to the lateral side of the patella allowed us to expose the external wing on which an external release of the patella was carried out. Fixing the graft was made, with transtendinous passage on the patellar tendon and quadriceps. Fixation on the femoral side was made by two anchors. Immobilization maintained for 45 days. Discussion: The surgical management of patellar instability on total knee prosthesis involves a diversity of surgical techniques which can be used alone or in combination depending on the etiology. Procedures involving soft tissues ranging from simple external release to MPFL plasties, as well as bone procedures which may require changing prosthetic parts in the event of a rotation defect. Conclusion: MPFL plasty is effective in the management of post-arthroplasty patellar instability and has its place in the treatment of patellar dislocations following total knee prosthesis. It is offered either as a complement to other procedures and in particular to a prosthetic revision