Deepening trochleoplasty with a thick osteochondral flap for patellar instability:Clinical and functional outcomes at mean 6 year follow-up

Background: In patients with patellar instability and severe trochlear dysplasia, trochleoplasty has become increasingly used as part of the surgical management. Hypothesis: Deepening trochleoplasty for severe dysplasia in patellofemoral instability improves function and increases sports participation. Study Design: Case series; Level of evidence, 4. Methods: Between 1995and 2010 the thick-flap deepening trochleoplasty was performed in 90 patients (107 knees) with severe trochlear dysplasia. Data was collected prospectively pre-operatively, at 6 weeks and 1-year follow-up. The patients were surveyed retrospectively to determine the clinical and functional outcomes including sports and exercise participation at a minimum of 2 years, with complete data available in 92%. Results: With a minimum follow-up of 2 years, average of 6 years (range 2 – 19 years). The Kujala score had a median and interquartile range (IQR) of 63 (47-75) pre-operatively rising to 79 (68-91) at 1 year follow-up and 84 (73-92) at final follow-up (p< 0.05). Seventy-two per cent were satisfied with their knee function at 1 year follow-up rising to 79% at final follow-up (p <0.0001). Sports and exercise participation increased from 36 patients (40%) pre-operatively to 60 (67%) at final follow-up. The numbers involved in competitions increased slightly from 10 (11%) to 11 (12%). Of those sports that involved twisting (e.g. soccer, cricket, badminton), the proportion of patients participation increased from 16 (18%) to 22 (24%), whereas in non-twisting sports (e.g. running, swimming, cycling) it increased from 24 (27%) to 47 (52%) of whom 14 (16%) used walking as exercise. Conclusion: The thick-flap deepening trochleoplasty improves the clinical and functional outcomes for patients with symptomatic patellar instability with severe trochlear dysplasia. These results improve over time and beyond the 1 year clinical follow-up. However trochleoplasty does not lead to a significant improvement in sports participation at a competitive level. It does improve the sports and exercise patient participation, principally in non-twisting sports activities

Classification of trochlear dysplasia as predictor of clinical outcome after trochleoplasty

PURPOSE: Sulcus-deepening trochleoplasty restores the trochlear groove in patients with patellofemoral instability and underlying trochlear dysplasia. There are types of dysplasia both with (B and D) and without (A and C) a supratrochlear spur. The aim of this study was to identify influencing factors for the clinical outcome following trochleoplasty. METHODS: Forty-four knees in 38 patients who underwent trochleoplasty for instability (type A in 9, B in 15, C in 9 and D in 11 knees) were assessed clinically with the Kujala score and radiologically with radiographs and MRI. The median follow-up was 4 (2-7.8) years. RESULTS: At follow-up, the median Kujala score had improved from 68 (29-84) to 90 (42-100) points (P < 0.001). Instability (P < 0.001) and pain (P = 0.027) decreased significantly, but in 3 knees, pain was worse postoperatively. Twenty-seven knees were ranked as excellent, 10 as good, 2 as fair and 5 as poor. Overall, dysplasia types B and D benefited more from surgery than types A and C. The postoperative MRI revealed no chondrolysis or subchondral necrosis, but deterioration of cartilage on the lateral trochlear facet was identified. CONCLUSION: Trochleoplasty is a useful and reliable surgical technique to improve patellofemoral instability in patients with a dysplastic trochlea. While improved stability is predictable, pain is less predictable and may even increase following surgery. The overall results were directly dependent on the type of the dysplasia, with a significantly better clinical outcome in type B and D. The clinical relevance of this study is that severe dysplasia can successfully be treated with trochleoplasty. LEVEL OF EVIDENCE: III