Clinical Efficacy of Distal Femoral Derotational Osteotomy Combined with Tibial Tubercle Osteotomy for Failed Medial Patellofemoral Ligament Reconstruction

Cao Yanwei; Liu Yang; Wang Daofeng; Zhang Hui

Abstract：Objective To evaluate the clinical outcomes of medial patellofemoral ligament(MPFL)reconstruction combined with distal derotational femoral osteotomy(DDFO)for the treatment of failed primary MPFL reconstruction.Methods A retrospective analysis was conducted on data of 15 patients(15 knees)with recurrent patellar dislocation treated at Beijing Jishuitan Hospital,Capital Medical University,between January 2012 and January 2024.The cohort included 2 males and 13 females,aged 15～30 years with a mean age of(21.2±4.6)years.All patients had undergone primary MPFL reconstruction,with a mean time to failure of(21.2±4.6)months.The revision procedures were as follows:10 knees underwent MPFL reconstruction combined with DDFO;2 knees underwent MPFL reconstruction combined with DDFO and medial tibial tubercle transfer;and 3 knees underwent MPFL reconstruction combined with DDFO,medial tibial tubercle transfer,and distal tibial tubercle transfer.Radiographic parameters and functional scores were compared before and after surgery.Results The mean postoperative follow-up duration was(34.1±9.4)months(range,20～42 months).Significant improvements were observed in all radiographic parameters postoperatively:The patellar tilt angle decreased from(42.3±15.4)° to(18.6±14.2)°;the femoral anteversion angle decreased from(41.3±13.0)° to(13.6±6.2)°;the Caton index decreased from(1.3±0.3)to(1.1±0.1);the tibial tubercle-trochlear groove distance decreased from(24.3±6.6)mm to 15.3±4.9 mm;and the patellar laxity index decreased from(84.4±20.6)％to(17.2±8.9)％(P＜0.001).The proportio n of patients with a high-grade"J-sign"decreased from 100％preoperatively to 7％postoperatively.At the final follow-up,all patient-reported outcome measures—including the Tegner score,Kujala score,Lysholm score,and international knee documentation committee subjective score—showed significant improvement compared to preoperative values(P＜0.001).Conclusion For revision surgery in patients with failed MPFL reconstruction and severe femoral anteversion,MPFL reconstruction combined with DDFO can improve both radiographic parameters and subjective functional scores.Furthermore,malposition of the femoral tunnel was not identified as the primary cause of failure.