A retrospective Follow-Up after derotational distal femoral osteotomy combined with medial patellofemoral ligament reconstruction for the treatment of recurrent patellar dislocation

OBJECTIVE: To assess the clinical efficacy of medial patellofemoral ligament reconstruction (MPFL-R) combined with medial-approach derotational distal femoral osteotomy (DDFO) in the treatment of recurrent patellar dislocation (RPD). METHODS: In this retrospective Level IV case series, we reviewed 45 patients with recurrent patellar dislocation (2 males, 43 females; age 13-44 years, mean 22.8 ± 6.0 years) and a femoral anteversion angle (FAA) > 30° as measured using the Jarrett method (Kaiser et al. in Arch Orthop Trauma Surg 136(9):1259, 2016), who underwent combined medial patellofemoral ligament reconstruction (MPFL-R) and medial-approach derotational distal femoral osteotomy (DDFO) between January 2018 and January 2022. Clinical and radiographic parameters were assessed preoperatively and at a minimum two-year follow-up, including J-sign grading, visual analogue scale (VAS) pain score, Caton-Deschamps index (CD-I), FAA, patellar tilt angle (PTA), tibial tubercle-trochlear groove (TT-TG) distance, and patient-reported outcome measures (PROM) scores (Tegner, Kujala, and Lysholm). A subgroup analysis compared outcomes between patients who did and did not undergo adjunctive tibial tubercle osteotomy (TTO). RESULTS: At the two-year follow-up, patients demonstrated significant improvements in J-sign grading, VAS pain scores, femoral anteversion angle, patellar tilt angle, TT-TG distance, and functional outcomes (Tegner, Kujala, and Lysholm scores) (all P < 0.05). The Caton-Deschamps index showed no significant change (P > 0.05). In subgroup analysis, the TTO cohort experienced a greater reduction in TT-TG distance than the non-TTO cohort (P < 0.05), whereas postoperative VAS, Kujala, and Lysholm scores did not differ significantly between groups (P > 0.05). CONCLUSION: Medial patellofemoral ligament reconstruction combined with medial-approach derotational distal femoral osteotomy effectively restores patellofemoral stability and enhances functional outcomes in patients with recurrent patellar dislocation and excessive femoral anteversion. The indication for concomitant tibial tubercle osteotomy should be individualized according to each patient's specific anatomical and clinical characteristics.