The Role of Medial Retinaculum Plication Versus Medial Patellofemoral Ligament Reconstruction in Combined Procedures for Recurrent Patellar Instability in Adults

Background: The comparative clinical outcome of medial retinaculum plication (MRP) versus medial patellofemoral ligament reconstruction (MPFLR) for recurrent patellar instability in adults is unknown.

Hypothesis: Arthroscopic MRP can yield similar results to MPFLR for recurrent patellar instability in adults.

Study Design: Randomized controlled trial; Level of evidence, 2.

Methods: One hundred patients with recurrent patellar instability were randomly divided into 2 groups receiving either arthroscopic MRP or MPFLR. Lateral release and anteromedial or distal tibial tubercle transfers were also performed as indicated. Follow-ups were performed at 12, 24, and 60 months postoperatively, and computed tomography (CT) was performed immediately after the operation and at follow-up. The passive patella glide test was performed before surgery and at each follow-up point. The degree of knee function was evaluated preoperatively and at 2 and 5 years postoperatively using the International Knee Documentation Committee (IKDC), Lysholm, and Kujala rating scales. Survival analysis was performed, and redislocation or multiple episodes of patellar instability were considered as indicating failure.

Results: Forty-three patients in the MRP group and 45 patients in the MPFLR group were followed for 5 years and received complete evaluations. The correction of the static patellar position deteriorated over time in both groups, but significantly better results were observed for the MPFLR group. The results of the passive patella glide test indicated more stable patellae in the MPFLR group at each follow-up point. Functional evaluations at 2 and 5 years (final Lysholm score, 69.3 ± 6.9 vs 86.9 ± 6.1; Kujala score, 73.8 ± 5.5 vs 87.4 ± 5.7) revealed statistically significant superior results in the MPFLR group. Finally, 4 patients (9.3%) in the MRP group and 1 (2.2%) in the MPFLR group experienced episodes of redislocation, and 7 patients (16.3%) in the MRP group and 3 (6.7%) in the MPFLR group experienced multiple episodes of patellar instability (P = .037). Kaplan-Meier survival analysis and a log-rank test indicated better results and a significantly higher survival rate (P = .006) in the MPFLR group.

Conclusion: MPFLR results in better static patellar position and functional outcome than MRP in the treatment of recurrent patellar dislocation in adults.