Temporary Proximal Radioulnar Joint Transfixation and Biceps Chemodenervation for Recurrent Anterior Radial Head Instability After Monteggia-Variant Injury: A Case Report

Monteggia-variant injuries are complex elbow fracture-dislocations in which restoration of ulnar alignment typically results in stable reduction of the radial head. Persistent radial head instability following otherwise successful ulnar fixation is uncommon and clinically challenging. We report the case of a 68-year-old man with a Monteggia-variant injury consisting of an ulnar shaft fracture, ulnohumeral dislocation, and posterior radial head dislocation treated with ulnar open reduction and internal fixation and lateral ulnar collateral ligament repair. Despite initial stability, early postoperative imaging demonstrated recurrent anterior radial head dislocation with maintained ulnar alignment and a stable ulnohumeral joint. Dynamic instability was attributed to loss of anterior soft tissue restraint combined with biceps-driven anterior translation of the proximal radius. Revision management consisted of temporary transfixation of the proximal and distal radioulnar joints using Kirschner wires to stabilize the radial head while preserving ulnohumeral motion, along with adjunctive botulinum toxin injection of the biceps. Pins were removed at 3 weeks, at which point the patient maintained excellent elbow flexion and extension. By 11 weeks, the patient had regained near-full elbow motion and forearm rotation without recurrent instability. Temporary radioulnar joint transfixation combined with targeted chemodenervation may provide a simple, anatomy-driven strategy for managing persistent anterior radial head instability while preserving ulnohumeral motion during early recovery.