Osteosarcoma in olecranon of 20-year-old man. Patient reported right elbow pain 3 years after resection of femoral osteosarcoma. A and B, Lateral and anteroposterior radiographs of right elbow appear normal. C, MR image clearly shows lesion in olecranon. Incisional biopsy revealed osteosarcoma. D, Biopsy scar. E, Incision was made over subcutaneous border of proximal ulna, leaving biopsy track intact. F, Ulnar osteotomy was performed distally to ensure wide margin. Ulnar nerve isolated and protected while proximal ulna was resected with wide margins. G, Specimen removed from field. H and I, Allograft of proximal ulna with triceps tendon cut and placed in defect. J, Allograft was fixed to distal ulna using 3.5-mm dynamic compression plate. Triceps tendon and elbow joint capsule are repaired. K, Wound was covered with free gracilis flap and split-thickness skin graft. L, Photograph of cut specimen after removal of soft tissue. SEETECHNIQUE 24.7.