Use of an ipsilateral vascularized ulnar transposition autograft for limb-sparing surgery of the distal radius in dogs: an anatomic and clinical study.

To develop a surgical technique for using the distal aspect of the ulna as a transposition autograft in a distal radial defect and to assess patency of vascular supply and viability of the distal ulna in a heterotopic position.Cadaveric study and clinical cases.Twenty-two normal canine thoracic limbs; 3 dogs with distal radial osteosarcoma.The arteries and veins of 12 limbs were injected with latex. Barium sulfate suspension was injected into the brachial artery of 10 other limbs after removal of the distal radius only (n = 2), ulna transposition (UT) (n = 6), or no procedure (n = 2). The distal ulna grafts were then harvested and decalcified in formic acid. The grafts were cut into 3-5 mm transverse sections and radiographed with a nonscreen film system to determine filling of intramedullary vessels with barium suspension. UT was performed in 3 dogs with distal radial osteosarcoma. Bone scintigraphy was performed 2-7 days after surgery to assess viability of the transposed ulna graft.Angiography confirmed patency of the caudal interosseous artery in all but 2 limbs in which the UT technique was performed; however, barium-filled vessels were identified in the medullary cavity of all ulnar grafts. Scintigraphy confirmed graft viability in the 3 dogs, all of which had good to excellent limb function.The distal aspect of the canine ulna can be used as a vascularized transposition autograft to replace distal radial defects, and viability can be maintained.The UT technique appears to be an acceptable limb-sparing technique for dogs with tumors of the distal aspect of the radius.