Proximal Radioulnar Synostosis Post-radial Head Fracture: Surgical Excision and Anconeus Muscle Flap Interposition for Functional Restoration

Adult proximal radioulnar synostosis is a rare complication where its manifestation is due to either post-surgery or post-traumatic effect causing limitation in the function of the forearm especially in supination and pronation. Most common occurrences of synostosis over the forearm region can be divided based on anatomical location, which involves the distal third, middle third, and proximal third forearm region. We report the case of a 42-year-old woman who developed proximal radioulnar synostosis following a conservatively treated radial head fracture 18 months earlier. She presented with pain and restricted forearm rotation during heavy lifting. Surgical excision of the synostosis with anconeus muscle flap interposition was performed. Four months postoperatively, the patient demonstrated improved pronation and supination with no further complaints. Surgical intervention should be considered in adult cases where forearm rotation is compromised.