Classification of trochlear dysplasia as predictor of clinical outcome after trochleoplasty

• Published in: Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA Vol. 19; no. 10; pp. 1655 - 1661
• Main Authors: Fucentese, Sandro F., Zingg, Patrick O., Schmitt, Jürgen, Pfirrmann, Christian W. A., Meyer, Dominik C., Koch, Peter P.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.10.2011; Springer Nature B.V
• Subjects: Adolescent; Adult; Arthroplasty - methods; Classification; Clinical outcomes; Female; Humans; Joint Instability - etiology; Joint Instability - surgery; Knee; Knees; Male; Medicine; Medicine & Public Health; Orthopedics; Patellofemoral Joint - pathology; Patellofemoral Joint - surgery; Patients; Retrospective Studies; Sports; Surgery; Treatment Outcome; Young Adult; Trochlear dysplasia; Patellofemoral instability; Trochleoplasty
• ISSN: 0942-2056; 1433-7347
• DOI: 10.1007/s00167-011-1410-7

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.