Osteosynthesis in Forearm Transplantation Using a Novel Ulnar-Shortening Osteotomy System for Simultaneous Both Bone Fixation

Introduction: Osteosynthesis in forearm-level allotransplantation is technically challenging. Achieving adequate cortical contact simultaneously between the radius and ulna proves difficult due to differing bone morphology of donor and recipient. In addition, the large area of dissection around the osteotomy sites and use of immunosuppressants further deters osseous healing, making nonunion a significant risk. Methods: Seven distal forearm transplants were performed on cadavers using the Newclip Technics ulnar-shortening osteotomy system for both the radius and ulna. The donor bones were plated after placing two transverse 0.062 K-wires distally for DRUJ stabilization. The osteotomy cut-guides were screwed to the plates and oblique osteotomies were performed. Matching recipient osteotomies were performed using the same cut-guide system. The donor and recipient were then brought together and any discrepancies in length corrected. The osteosynthesis site is then compressed and an interfragmentary lag screw placed across the osteosynthesis. Results: The Newclip system enables precise osteosynthesis in cadaver distal forearm transplants. Targeted radial and ulnar lengths are reliably achieved while maintaining accurate control of ulnar variance. Multiple osteotomy slot options on the cut guides allow titration of bone length. Oblique osteotomies enable increased cortical contact and an interfragmentary lag screw for additional stabilization. Conclusions: The capability to perform osteotomies, compression, and fixation of both radius and ulna simultaneously using this technique allows for reliable and precise hand transplantation osteosynthesis. This technique will be an effective tool until patient-specific instrumentation derived from computer-aided design can be expeditiously manufactured and made widely available.