Osteosarcoma of the patella: biologic reconstruction with allograft.

Osteosarcoma rarely occurs in the patella. The majority of lesions located in the patella are usually benign. According to the literature, osteosarcoma of the patella has been reported in 32 cases. Surgical treatment (patellectomy, resection and arthrodesis with allograft, and total joint replacement) was attempted in several cases, but neither function of the knee joint nor prognosis of the patients were good. A 53-year-old woman reported pain and swelling in the left knee. Based on plain radiographs and magnetic resonance imaging (MRI), a bone tumor was suspected, and an open bone biopsy of the patella was performed. The pathologic diagnosis was osteoblastic osteosarcoma. A total patellectomy was performed because MRI showed a lesion that did not spread into the joint. A reconstruction was subsequently performed by allograft patella. The graft consisted of a quadriceps tendon, a patella with a patellar tendon, and the medial and lateral retinacula. Twenty-six months postoperatively, the function of the knee joint was almost similar to that before the procedure, and there was no evidence of recurrence or metastasis. After the procedure, the patient could walk without pain and the knee joint could flex to 140 degrees with extension lag of 10 degrees . To our knowledge, this is the first report of a biologic reconstruction with allograft patella after total patellectomy in osteosarcoma involving the patella.