Trochleoplasty is a Viable Option for Patellar Instability in Patients with Severe Trochlear Dysplasia: Early Outcomes Analysis of the U.S. Experience

OBJECTIVES: Patellar instability caused by severe trochlear dysplasia is best treated by sulcus-deepening trochleoplasty. There have been no studies examining outcomes after this procedure in the United States. The purpose of this study was to evaluate the early outcome data of patients undergoing sulcus-deepening trochleoplasty for high-grade trochlear dysplasia at our institution. METHODS: A total of 43 patients (49 knees) with severe trochlear dysplasia were prospectively enrolled and underwent sulcus-deepening trochleoplasty. 23 out of 49 (46.9%) knees had prior surgery related to patellar instability, and six knees had more than one such surgery. Concomitant procedures during the trochleoplasty included medial patellofemoral ligament reconstruction (100%), lateral release (49.0%), tibial tubercle osteotomy (36.7%), and some type of cartilage procedure (49.0%). Physical examination, radiographic analysis, and clinical follow up were obtained for all patients. Patients also completed pre and postoperative Kujala and IKDC scores, in addition to reporting on return to sport and any instances of recurrent instability. RESULTS: 79.6% of patients were female with an average age of 20.1 +/- 6.3 years. Follow up ranged from 6 weeks to 49 moths (mean 10.6 +/- 10.5 months). There were no episodes of recurrent instability. All patients reported clinically significant improvements compared with baseline preoperative outcome scores. Patellar tracking was normal in all cases with no patellar apprehension at final follow up. The mean preoperative IKDC score was 49.6, which improved to 78.3 (p < 0.001), and the mean preoperative Kujala score was 54.5 which improved to 82.8 (p < 0.001). Patients reported high satisfaction rates (mean 9.3 +/- 1.8 out of 10), and 81.5% patients were able to return to sport. 9 knees (18.4%) developed arthrofibrosis and required manipulation under anesthesia, 7 of which underwent simultaneous arthroscopic lysis of adhesions. At the latest follow-up, average knee range of motion was 126.6 +/- 13.7 degrees. Radiographic analysis of the sulcus angle demonstrated a significant decrease from 144.2 degrees preoperatively to 133.0 postoperatively (p < 0.001). CONCLUSION: When indicated in the setting of severe trochlear dysplasia, sulcus-deepening trochleoplasty can provide a reliable and successful surgical solution to recurrent patellar instability. Early follow up demonstrates improved radiographic parameters coupled with excellent clinical outcomes and no recurrent instability.