Medial patellofemoral ligament reconstruction combined with derotational distal femoral osteotomy yields better outcomes than isolated procedures in patellar dislocation with increased femoral anteversion

Abstract

Purpose: The purpose of this study was to evaluate and compare clinical and radiological outcomes between isolated medial patellofemoral ligament reconstruction (MPFLR) and MPFLR combined with derotational distal femoral osteotomy (DDFO) for patellar dislocation with increased femoral anteversion (FA).

Methods: Between 2014 and 2019, 36 patients who underwent isolated MPFLR and 31 patients who underwent MPFLR combined with DDFO were retrospectively included. Clinical outcomes included physical examinations, functional outcomes (Kujala, Lysholm, International Knee Documentation Committee (IKDC), and Banff Patella Instability Instrument (BPII) scores), activity level (Tegner activity score and return to sports), complications, and patellar re-dislocation rate. Radiological outcomes included patella tilt angle, patellar congruence angle, and patella-trochlear groove distance.

Results: All clinical outcomes improved significantly in both groups, but the DDFO group had significantly better postoperative scores than the MPFLR group (Kujala: 85.1 ± 7.7 vs. 80.5 ± 8.4, P = 0.023; Lysholm: 86.8 ± 8.2 vs. 81.9 ± 9.1, P = 0.026; IKDC: 86.2 ± 10.0 vs. 81.7 ± 8.1, P = 0.045; and BPII: 68.0 ± 12.5 vs. 62.3 ± 10.0, P = 0.039). Both groups achieved successful return to sports (90.3% vs. 91.7%). No re-dislocation or major complications occurred. Radiological outcomes improved significantly in both groups, but the DDFO group had better outcomes (P < 0.05). The tibial tubercle-trochlear groove distance was only improved after DDFO from 17.0 ± 2.3 mm to 15.1 ± 2.0 mm (P = 0.001).

Conclusion: Both isolated MPFLR and MPFLR combined with DDFO yielded satisfactory clinical and radiological outcomes in the treatment of patellar dislocation with increased FA. However, combined DDFO had better outcomes and should be considered a priority.

Level of evidence: Level III.

Keywords: Derotational distal femoral osteotomy; Femoral anteversion; Functional outcomes; Medial patellofemoral ligament reconstruction; Patellar dislocation; Patellofemoral congruence.