Is there a place for MPFL reconstruction in a total knee arthroplasty?

Background: Patellofemoral instability (PFI) is a significant cause of failure following total knee arthroplasty (TKA), manifesting as anterior pain, component wear, or dislocation. While often attributed to component malalignment in the axial, frontal, or sagittal planes, PFI also results from soft-tissue imbalance or improper trochlear design.

Objective: This article evaluates the diagnostic framework for post-TKA patellar instability and describes the indications and surgical technique for medial patellofemoral ligament (MPFL) reconstruction as a corrective procedure.

Key Points: Diagnosis requires a comprehensive physical examination and radiographic assessment, including computed tomography (CT) to quantify component rotation. Combined internal rotation of the femoral and tibial components exceeding 8° is strongly associated with dislocation. While implant revision is preferred for severe malalignment, MPFL reconstruction using a pedunculated quadriceps tendon strip offers a lower-morbidity alternative for patients with correctly positioned implants or those unsuitable for major revision. The technique involves harvesting a 10-cm graft from the mid-third of the quadriceps tendon, maintaining its patellar attachment, and securing it at the femoral isometric point with an interference screw at 30° of flexion. Clinical series indicate that MPFL reconstruction, often combined with lateral retinacular release or tubercle medialization, effectively prevents recurrent dislocation and improves functional outcomes.

Conclusion: MPFL reconstruction is a viable therapeutic option for managing patellar instability after TKA when primary implant positioning is satisfactory. Success depends on precise patient selection and addressing concomitant soft-tissue or bony deficiencies to ensure stable patellar tracking.