Knee Pain - Exercise

Abstract

HISTORY: A 58-year-old male presented with a 4-week history of spontaneous knee pain. One year prior to presentation, he had bariatric surgery and increased his exercise regimen resulting in a 100 lb weight loss. He denies trauma or inciting injury. His pain localized to the posterolateral knee and is described as a 5/10 cramping pain. He describes a popping sensation and experiences a snapping moment in the lateral knee with deep squatting. He denies swelling and ecchymosis. He has tried ice, physical therapy and ibuprofen without relief. PHYSICAL EXAMINATION: Focused left knee exam revealed a palpable cystic structure in the lateral popliteal fossa. There is tenderness over the lateral joint line with no instability of the proximal tibiofibular joint or biceps femoris tendon. Range of motion was 0-140° with pain greater than 120° of flexion. When the knee is brought into deep flexion, there is an audible pop over the lateral aspect of the knee. When the knee is then brought into extension, there is reproduction of an audible pop and snapping moment of the lateral knee at end range extension. Flexion McMurray’s test is positive. Strength, reflexes, sensation, and pulses are normal throughout. DIFFERENTIAL DIAGNOSIS: 1. Snapping biceps femoris tendon 2. Snapping popliteus tendon 3. Lateral meniscus tear 4. Iliotibial band friction syndrome 5. Proximal tibiofibular joint instability TEST AND RESULTS: Three view x-rays of left knee: • Medial joint space narrowing. No acute fracture. Dynamic ultrasound of the left knee: • Normal biceps femoris tendon. Popliteal cyst noted. MRI of left knee without contrast: – Incomplete discoid lateral meniscus and small multiseptated popliteal cyst noted. FINAL WORKING DIAGNOSIS: Left knee discoid lateral meniscus with subluxation of the meniscus TREATMENT AND OUTCOMES: 1. Patient counseled on activity modification. 2. Dynamic ultrasound revealed no evidence of hamstring irregularities. 3. Unsuccessful ultrasound-guided aspiration of popliteal cyst attempted followed by an intra-articular corticosteroid injection. 4. After MRI evaluation, orthopedic surgery performed an arthroscopic partial meniscectomy of subluxing torn posterior horn and midbody saucerization of lateral meniscus. 5. He tolerated surgery well with no further subluxation of his meniscus in physical therapy.