The Journal of Bone and Joint Surgery

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An Ossifying Popliteal Mass¹
A forty-two-year-old male truck driver had persistent discomfort in the right popliteal fossa for four months. Previously, he had been healthy and he had no history of trauma. He reported the gradual onset of severe pain and tenderness and had noticed swelling in the right popliteal fossa and calf with paresthesias and decreased sensation in the right leg.
Physical examination disclosed a hard, bone-like mass in the right popliteal fossa with a positive Tinel sign in the distribution of the tibial nerve. The patient had an antalgic gait, muscular atrophy in the right thigh, and swelling in the right calf. The range of knee motion was restricted to −10° to 110°. A neurologic evaluation revealed decreased sensation to light touch in the right leg and foot. Manual muscle testing showed slight weakness of plantar flexion of the ankle. He had a normal white blood-cell count, a normal C-reactive protein level, and an erythrocyte sedimentation rate of 22 mm/hr. The serum level of alkaline phosphatase was within the normal range.
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