Purpose: (1) To report the clinical and radiological outcomes of a surgical technique combining anatomic medial patellofemoral ligament reconstruction and tibia tuberosity transfer in adolescents with patella alta and elevated tibial tuberosity-trochlear groove (TT -TG) distance in the treatment of recurrent patellar dislocation; and (2) to investigate the potential risks of growth arrest or developmental deformities associated with this combined technique. Methods: Medical records of patients who underwent the combined surgery from 2015 to 2019 were reviewed. This study included adolescents aged between 14 and 18 years with a Caton -Deschamps index (CDI) > 1.30 and TT -TG distance > 20 mm, with a minimum follow-up of 4 years. Radiological examinations including lateral views and fulllength posteroanterior standing radiographs were investigated to assess patella height by CDI, posterior tibial slope (PTS) angle, side -to -side difference in bone length, and lower extremity alignment by hip -knee -ankle angle; computed tomography scans and magnetic resonance imaging pro fi les were investigated to evaluate TT -TG distance and staging of growth plate closure. Other evaluations included preoperative and postoperative physical examination, Kujala score, and Tegner activity score. The patients were strati fi ed into 3 subgroups according to an magnetic resonance imaging e based staging system of the growth plate closure, and each outcome was analyzed. A cohortspeci fi c minimal clinically important difference estimation was performed using standard error of measurement. Results: The average age at the time of surgery was 16.1 years (range, 14.1-17.8). The average follow-up was 5.6 years (range, 4.0-7.6). No recurrent dislocation occurred, and no clinically signi fi cant deformity or axis deviation was encountered. Postoperative patellar height by CDI was 1.00 +/- 0.11 (range, 0.81-1.15). No signi fi cant differences were found in the preoperative and postoperative hip -knee -ankle angle or side -to -side difference in femur/tibia length among all subgroups. A signi fi cantly decreased PTS angle was found in patients with open growth plates, from 10.2 degrees +/- 1.7 degrees before surgery to 8.1 degrees +/- 1.0 degrees after surgery ( P = .015). The Kujala score and Tegner score both signi fi cantly improved, from 65.5 +/- 13.9 before surgery to 90.4 +/- 7.2 after surgery in the Kujala score ( P < .001) and from 4.0 +/- 1.1 before surgery to 4.7 +/- 1.3 after surgery in the Tegner score ( P < .001). Of the whole cohort, 63.1%, 100%, 47.1%, and 94.1% of patients achieved the minimal clinically important difference for PTS angle, CDI, Tegner score, and Kujala score, respectively. Conclusions: This combined technique is safe and effective in treating recurrent patellar dislocation in skeletally mature adolescents with concurrent patella alta (CDI > 1.30) and TT -TG distance > 20 mm, permitting patients to have improved knee function and low complication rates. Nonetheless, patients with open growth plates demonstrated a decrease in PTS, which might predispose the knee to recurvatum and osteoarthritis in the long term. Level of Evidence: Level IV, controlled case series.
