Failures and Complications with MPFL reconstruction: Our experience in 215 patients

INTRODUCTION: Chronic lateral patellar instability is one of the commonly seen clinical conditions encountered by knee surgeons. Medial patellofemoral ligament (MPFL) reconstruction has become mainstay treatment over the last three decades. Upto 26% complication rates have been reported in literature with MPFL reconstruction. The purpose of this study is to analyse failure rates, complications of surgery for PF instability and to identify the predictive factors for failure. METHODS: A retrospective analysis of prospectively collected data was performed of all 215 (234 knees) patients who had undergone MPFL reconstruction between October 2007 and August 2018. All the cases with any postoperative complications or failures were included. A failure was defined by a postoperative patellar dislocation or surgical revision for recurrent patellar instability or anterior knee pain not resolving with conservative methods. Other complications such as stiffness, infection, neurological deficit and deep vein thrombosis were also included. Lysholm, Kujala, Tegner and radiographic features, such as trochlear dysplasia according to Dejour classification, patellar height with the Caton-Deschamps index (CDI), tibial tubercle-trochlear groove distance were analysed pre and post operatively. RESULTS: Ten patients (4.27%) had a revision of MPFL reconstruction, seven patients (3%) had removal of their metal work. Post-operative stiffness was in only three patients (1.28%) and required manipulation under anesthesia. Six patients (2.56%) had patellofemoral replacement over time while three patients had arthroscopic debridement for cartilage related pathology. There was also one case each of femoral nerve palsy(related to the nerve block), post-operative deep infection, deep vein thrombosis?. CONCLUSION: To our knowledge, this is the only study recording the failures and complications of MPFL reconstruction on a large patient database. Age above 30, obesity, cartilage lesions, hyperlaxity and female gender are predictors of a poor subjective outcome. Identifying the potential risk factors preoperatively can prevent future complications.