Influence of patient-related factors on clinical outcome of tibial tubercle transfer combined with medial patellofemoral ligament reconstruction

Background: Tibial tubercle transfer is frequently used for treating patellar instability. This study aimed to analyze the clinical results following tibial tuberosity transfer with medial patellofemoral ligament (MPFL) reconstruction in the treatment of patellar instability. Methods: Seventy-two cases presenting a lateralized tibial tubercle were treated with tibial tuberosity transfer and MPFL reconstruction. Pre-operative and postoperative pain levels and knee function were evaluated using common scoring systems. Cartilage status was assessed at the time of surgery, and the influence of patient-related factors was analyzed. Median and interquartile ranges were used to present the results. Results: After a mean of 27.6 (12 -76) months, a re-dislocation rate of 4.2% and significant improvement in knee function from a median of 48.0 (33 -70) to 83.0 (68 -94) and a median of 44.0 (24 -62) to 85.0 (69 -93), based on Kujala (P <= 0.001) and Lysholm (P <= 0.001) scores were observed. The Tegner score significantly increased from a median of 3.0 (2 -4) to 4.0 (4 -5) (P <= 0.001), while the pain level decreased from a median of 5.0 (3 -8) to 2.0 (0 -3) (P <= 0.001). Cartilage lesions were found in 55/72 (76.4%) knees. The likelihood of finding II degrees cartilage lesions was six times higher in cases of >= two previous operations. Conclusion: Tibial tuberosity transfer with MPFL reconstruction allowed reliable patellar stabilization with a low re-dislocation rate. Patient age and unsuccessful attempts at surgical stabilization posed significant risk factors for cartilage lesions and may have limited postopertive outcomes. (C) 2018 Elsevier B.V. All rights reserved.