Induced Membrane Reconstruction of a 6-cm Ulnar Defect With Concurrent Revision Bone Grafting of Radial Nonunion Following Gustilo-Anderson Type IIIB Open Forearm Fracture: A Case Report.

The induced membrane technique (IMT) is a two-stage reconstructive procedure for critical-sized bone defects. We report a 31-year-old male who sustained a Gustilo-Anderson grade IIIB open fracture of the radius and ulna following a high-energy dirt bike injury, complicated by Serratia marcescens fracture-related infection and septic nonunion. Intraoperative debridement at Stage 1 revealed a 6-cm defect of the ulna, which was managed with an antibiotic-impregnated polymethylmethacrylate (PMMA) spacer. A concomitant radial nonunion, identified on postdebridement CT, was addressed at Stage 2 with concurrent revision open reduction and internal fixation (ORIF) and autogenous femoral bone grafting. Culture-directed oral antibiotic therapy was administered following Stage 1. Mature bridging callus was noted at 6 months and confirmed at both bones at approximately 22 months postinjury, with infection eradication confirmed at Stage 2. Prior to subsequent elbow procedures, the patient demonstrated a Mayo Elbow Performance Score of 65 (fair), with an elbow arc of motion of 60°-140° and forearm rotation of 70° pronation and 75° supination. This case illustrates the utility of IMT for ulnar reconstruction in the setting of fracture-related infection, and highlights a forearm-specific biomechanical consideration: Fixing the ulna at a set length via the IMT spacer construct while shortening the radius for nonunion compression may alter radioulnar variance, a single-case observation that we hypothesize could have implications for DRUJ and elbow mechanics and warrants further study.