Patellofemoral Stabilization: Postoperative Redislocation and Risk Factors Following Surgery

BACKGROUND: Patellofemoral instability is a common knee problem that is difficult to manage owing to its multifactorial etiology as well as the fact that predisposing pathoanatomic features vary from individual to individual. There is limited knowledge regarding the demographic and pathoanatomic risk factors or the relationship between these risk factors and the redislocation rate after surgical stabilization for this challenging condition. PURPOSE: To analyze the postoperative redislocation rates and the prevalence of demographic and pathoanatomic risk factors for patients undergoing a patellofemoral stabilization. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Patients with symptomatic recurrent patellofemoral instability underwent a soft tissue patellofemoral stabilization procedure. A total of 342 patellofemoral stabilization procedures (reconstruction, n = 256; imbrication, n = 86) were assessed at a mean follow-up of 24.3 months. Concomitant procedures were performed in accordance with the à la carte concept of addressing significant anatomic or biomechanical characteristics. Two surgical cohorts were analyzed separately for reconstruction or imbrication to address laxity of the medial patellofemoral ligament (MPFL). Failure of the patellofemoral stabilization procedure was defined as postoperative redislocation of the patella. Prevalence of demographic and pathoanatomic risk factors was determined for all patients. Disease-specific patient-reported outcomes were assessed with the Banff Patella Instability Instrument (BPII). RESULTS: A redislocation rate of 5.1% was identified for MPFL reconstruction and 20.9% for MPFL imbrication. For both MPFL procedures, age at time of surgery was significantly younger for the failed group as compared with the intact group. Postoperative BPII scores were significantly lower for patients who subsequently experienced a surgical failure as compared with intact surgery for both MPFL reconstruction (P = .048) and MPFL imbrication (P = .003). CONCLUSION: Patellofemoral stabilization with an à la carte approach to surgical selection demonstrated a low postoperative redislocation rate and good clinical results. Younger age at time of surgery was associated with surgical failure. This information may be used to guide surgical decision making and patient education.