Medial femoral condyle flap for ulnar reconstruction and structural bone allograft for radial reconstruction in post-traumatic forearm diaphyseal non-union: a two-case report

The successful treatment of forearm non-unions, which occur as a complication in 2-10% of all forearm fractures, poses a significant challenge in reconstructive surgery. Current treatment often involves revision fixation with non-vascularized bone grafts for atrophic non-unions. Large bony defects in both forearm bones, however, necessitate advanced reconstructive techniques. In isolated reconstructions of the radius or ulna, the vascularized medial femoral condyle (MFC) flap has gained popularity, achieving 98-100% union rate. Allogenic bone grafts have also been described for reconstruction of large bone defects, potentially reducing donor site morbidity and operation time. This two-case report investigates the performance of vascularized MFC cortico-cancellous flap for ulna reconstruction and tricortical allogenic bone graft of the iliac crest for radius reconstruction in excessive, post-traumatic, atrophic non-union of the forearm diaphysis. In May and June 2021, a 62-year-old and a 56-year-old male received reconstruction surgery 9 and 13 months after initial plate osteosynthesis after a motorcycle accident. The MFC flap showed successful bony union of the ulna after 3 months as well as consecutive remodeling. However, the reconstruction of the radius showed a recurrent non-union, which even led to plate breakage in one case. In both cases, ulnar reconstruction with a vascularized MFC flap achieved successful union. However, radial reconstruction using structural allograft did not achieve union, causing recurrent non-union, likely reflecting limited biological incorporation. Level of Evidence: V (Therapeutic).