Anterior Knee Pain In A Runner

Abstract

HISTORY: 40 yo F runner with bilateral, right, anterior, aching, intermittent, 3-10/10 knee pain. Wakes at night. Worse with going down stairs, running, fast walking. Better with rest and ibuprofen. ROS negative. PMHx: DVT, PE, depression, endometriosis, sleep apnea. PSHx: C-section, IVC filter. Meds: ibuprofen prn, citalopram, fluticasone nasal spray, Coumadin. FHx: DVT in father. SocHx: +tobacco, no alcohol or drug use; desk job; recreational runner. No recent immobilization/long travel. PHYSICAL EXAMINATION: BMI 38, vitals stable. Knee Exam: No malalignment, bruising, erythema, or obvious swelling; gait normal. Full AROM without pain; + patellar j sign; + patellar crepitus; 5/5 strength without pain; Neurovascularly intact. Negative patellar apprehension; equivocal patellar inhibition. positive patellar grind bilaterally. Full AROM. Negative bounce test, McMurray. Minimal tenderness of medial joint line. Palpable, firm 4cm mass in the right popliteal fossa that is mildly tender to palpation. No overlying skin changes. No ligamentous instability, calf pain, swelling, tenderness, warmth, erythema. Negative Homan’s sign. DIFFERENTIAL DIAGNOSIS: For mass: synovial/baker’s cyst, ganglionic cyst, meniscal cyst, DVT, aneurysm, muscular deformity, soft tissue mass TEST AND RESULTS: -2-view knee x-ray: ill-defined soft tissue sclerosis in the posteomedial right knee which could be a bone forming soft-tissue tumor, Moderate bilateral tricompartmental knee OA. -Knee MRIt: Round, lobular mass measuring 3 x 3 x 3.6 cm adjacent to the distal semimembranosus myotendinous junction. Central ossification and a thin rim of peripheral enhancement.A bone forming tumor, benign or malignant, is a possibility. -Bone tumor surgeon notified and patient seen. Felt unrelated to symptoms and likely secondary to prior trauma. CT knee and CXR. CXR normal. -CT without contrast: Soft tissue calcified lesion medial to the patient's small Baker's cyst partially surrounds the semitendinosus tendon. Tissue sampling is recommended to exclude a matrix forming neoplasm. Knee OA. -Sarcoma Tumor Board: benign; treat underlying knee pain. FINAL WORKING DIAGNOSIS: Benign soft tissue calcified lesion of the knee TREATMENT: symptomatic treatment, quit smoking, weight loss OUTCOME: asymptomatic at 2-months