Medial patellofemoral ligament reconstruction in skeletally immature patients: distal versus proximal femoral physis fixation

PURPOSE: To compare clinical outcomes and complications of medial patellofemoral ligament (MPFL) reconstruction using femoral fixation proximal versus distal to the physis in skeletally immature patients with patellar instability. METHODS: This retrospective study included 23 skeletally immature patients (24 knees) undergoing isolated MPFL reconstruction from January 2021 to August 2024. Patients were divided into proximal (n = 12 knees, mean age 14.1 ± 0.9 years ) and distal (n = 12 knees, mean age 13.8 ± 1.6 years ) physis fixation groups. Preoperative imaging assessed patellar height, trochlear dysplasia, and the tibial tuberosity-trochlear groove (TT-TG) distance. Clinical outcomes (Tegner, Kujala, Lysholm and International Knee Documentation Committee [IKDC]) and complications (re-dislocation, patellar fracture, infection, stiffness, quadriceps weakness and growth disturbance) were compared. RESULTS: The mean follow-up durations were 24.4 ± 4.3 months (range, 17-33) in the proximal group and 22.8 ± 4.7 months (range, 17-30) in the distal group (P = 0.374). Both groups showed significant improvements in all functional outcomes (P < 0.001) with no intergroup differences (P > 0.05). Subjective satisfaction was similar (8.5 vs. 8.3, P = 0.726). Return to sport occurred in 91.7% of both groups. Complication rates were numerically higher in the proximal group (41.7%; mainly knee pain (n = 3, 25%) and quadriceps weakness (n = 2, 16.7%) than in the distal group (24.9%; infection (n = 1, 8.3%), pain (n = 1, 8.3%), weakness (n = 1, 8.3%)(P = 0.667). No redislocations, patellar fractures, stiffness, or growth disturbances occurred. CONCLUSIONS: Both proximal and distal femoral physis fixation for MPFL reconstruction yield similar clinical outcomes and complication rates in skeletally immature patients. However, due to the limited sample size of this study, the current conclusion should be interpreted with caution.