INTRAMEDULLARY ENTRAPMENT OF THE RADIAL NERVE ASSOCIATED WITH HUMERALSHAFT FRACTURE

We present an unusual case of a humeral shaft fracture with intramedul lary entrapment of the radial nerve by an undisplaced posterior triang ular fragment tightly fixed to the lateral intermuscular septum. Initi al examination showed a complete high radial nerve palsy and an angula ted mid-shaft humeral fracture associated with an undisplaced posterio r triangular fragment. After failure of several closed reductions, we decided to attempt an open reduction and internal fixation with simult aneous exploration of the radial nerve. During surgery, the radial ner ve was found emerging from the medullary canal of the proximal fragmen t. The nerve was freed by briefly displacing the undisplaced posterior triangular fragment. The fracture was then reduced and fixed by plate and screws. Six months after the operation, there was full recovery o f the radial nerve and complete union of the fracture. Clearly, closed in tramedullary nailing would be contraindicated in this particular t ype of associated radial nerve injury. We therefore suggest that in ca ses of mid-shaft fractures of the humerus with associated radial nerve palsy, and an undisplaced posterior triangular fragment, consideratio n should be given to the possible entrapment of the radial nerve in th e medullary canal.