Correlation of ultrasound and magnetic resonance imaging with clinical outcome after patellar tenotomy: Prospective and retrospective studies

Objective: To report the appearances of ultrasound (US) and magnetic resona nce imaging (MRI before and after surgery for chronic patellar tendinopathy and to correlate postoperative appearances with clinical outcome. Design: A 12-month prospective longitudinal study and a retrospective study , each part using different patients. Prospec tive study included clinical assessment, ultrasound, and MRI all performed before and 12 months after su rgery. Retrospective study included ultrasound and clinical assessment only (i.e., no MRI) 24 to 67 months after surgery. Setting: Institutional athlete study group in Australia (Victorian Institut e of Sport Tendon Study Group). Patients: In the prospective study, 13 patients tall male; 15 tendons) who underwent patellar tenotomy; in the retrospective study, 17 different patie nts (18 tendons) who had undergone identical surgery. Main Outcome Measures: Ultrasound and MRI appearances and clinical assessme nt at baseline and 12 months after surgery (prospective study). Ultrasound appearance and clinical assessment 24 to 67 months after surgery (retrospec tive study). Dimensions of abnormal regions on imaging were measured. Clini cal assessment included categorical rating and numerical Victorian Institut e of Sport Assessment (VISA) score. Results: In the prospective study, preoperative ultrasound and MRI appearan ces confirmed the clinical diagnosis of patellar tendinopathy. Postoperativ e ultrasound and MRI also revealed abnormalities consistent with patellar t endinopathy. Despite this, 11 of 15 (73%) tendons were rated clinically as either good or excellent. Imaging modalities were unable to distinguish ten dons rated as good or excellent from those rated poor at 12 months. In the retrospective study, ultrasound images revealed abnormalities despite full clinical recovery. There was no correlation between dimension of ultrasound abnormality and either VISA score or time since surgery. Conclusion: After open patellar tenotomy, MRI and ultrasound findings remai n abnormal despite clinical recovery. Thus, clinicians ought to base postop erative management of patients undergoing patellar tenotomy on clinical gro unds rather than imaging findings. At present, there appears to be no role for routine postoperative imaging of patients recovering slowly after patel lar tenotomy. However, this is not to suggest that imaging cannot play a ro le in special circumstances.