020. DYNAMIC SONOGRAPHY IN QUADRICEPS TENDON IMPINGEMENT IN KNEE OSTEOARTHRITIS

Abstract

Background: Quadriceps tendon impingement has been described as an inflammatory process within the anterior suprapatellar fat and is a potential cause for anterior knee pain. It is diagnosed by MRI as a mass effect on quadriceps tendon. Methods: A 63-year-old female was referred to musculoskeletal ultrasound (US) clinic with history of right anterior knee pain of three year duration, which was increasing during the past four months. The pain was exacerbated by daily activities and relieved by rest. No history of major trauma, fracture or infection. The patient had history of Type 2 diabetes mellitus and hypertension. She had limited improvement with medical treatment and physical therapy. Results: The right knee showed swelling and tenderness over the quadriceps tendon and the range of motion showed flexion 1108 which was painful beyond 308 and extension was full but painful during the last 108. Plain X-ray anteroposterior (AP) and lateral views showed grade III osteoarthritis with a big osteophyte at the anterior aspect of femoral condyle. US imaging showed mild synovitis with effusion. Sonopalpation revealed tenderness and reproduction of patients symptoms. Dynamic US imaging of the right knee clearly demonstrated the impingement of the quadriceps tendon by the anterior osteophyte during flexion and extension of the right knee. Conclusion: To our knowledge, this is the first case using dynamic US imaging to report quadriceps tendon impingement due to an osteophyte. We highlight the role of US in such cases, especially if the findings on the screen are coupled with reproduction of the patient's symptoms.