Atraumatic Knee Swelling - Runner

Abstract

HISTORY: 38-year-old male runner with 4 months of left knee pain and swelling that he noticed worsened with running. He remembers no particular injury, increase in mileage, change in footwear, or systemic symptoms such as night sweats, weight loss, or other joint swelling. He was seen in urgent care with his exam showing an effusion and painful range of motion. He was diagnosed with a knee sprain, MRI ordered, and referred to sports medicine. In our clinic, he complained about anterolateral knee pain, persistent knee effusion, and inability to train because of pain and swelling. He denied locking or giving way. PHYSICAL EXAMINATION: Left knee with 1-2+ non-warm effusion, range of motion 0-130 degrees, lateral patellar facet tenderness, medial joint line tenderness, Lachman negative, valgus/varus testing stable, McMurray negative for click. DIFFERENTIAL DIAGNOSIS: 1. Medial meniscal tear 2. Patellar chondromalacia 3. Rheumatologic disorder 4. Pigmented nodular synovitis 5. Synovial chondromatosis TEST AND RESULTS: X-ray: small joint effusionMRI without contrast: large joint effusion, small medial meniscal tear, lateral patellar facet chondromalaciaArthrocentesis: 303,500 RBCs, 839 WBCs, no crystals; ESR 10, CRP 0.08, ANA negative, RF negative, Normal CBC; MRI with contrast: multiple round lesions on the medial posterior mid joint next to the proximal tibiofibular joint with peripheral enhancement consistent with pigmented villonodular synovitis vs infection FINAL WORKING DIAGNOSIS: 1. Pigmented villonodular synovitis 2. Medial meniscal tear 3. Patellar chondromalacia TREATMENT AND OUTCOMES: 1. Athlete was initially treated with physical therapy for the atraumatic meniscal tear. 2. Athlete had persistent effusion, with an aspiration that showed blood. This provoked review of prior MRI with concern of nodularity of synovium. Therefore an MRI with contrast was performed consistent with likely pigmented nodular synovitis. 3. Athlete evaluated by orthopedics for arthroscopy and synovial biopsy. Intraoperative findings included diffuse involvement of joint including anterior compartment, medial and lateral gutters, and the notch. Pathology consistent with pigmented villonodular synovitis. 4. Post op care complicated by poor progression of range of motion, current 10 to 70 degrees.