Posterior interosseous nerve entrapment after Monteggia fracture-dislocation in children.

OBJECTIVE: Although most of nerve injuries associated with Monteggia fracture-dislocation in children are neurapraxias and will recover spontaneously after conservative treatment, surgical exploration of the involved nerve is always required in the cases with the entrapment of posterior interosseous nerve (PIN). However, the necessity and time frame for surgical intervention for specific patterns of nerve dysfunction remains controversial. The aim of the report is to observe and understand the pathology of PIN injury associated with Monteggia fracture-dislocation in children, and to propose the possible indication for the exploration of nerve.

METHODS: Eight cases, six boys and two girls, with Monteggia fracture-dislocation complicated by PIN injury, managed operatively at the authors?Hospital from 2007 to 2008 were retrospectively reviewed. All the patients underwent the attempted closed reduction before they received exploration of PIN, with open reduction and internal fixation or successful closed reduction.

RESULTS: The PIN was found to be trapped acutely posterior to the radiocapitellar joint in 4 out of 5 Type III Bado's Monteggia fractures. In the remaining cases, since there were longer time intervals from injury to operation, chronic compressive changes and epineural fibrosis of radial nerve were visualized. After a microsurgical neurolysis performed, the complete recovery in the nerve function was obtained in all the cases during the follow-up.

CONCLUSION: The findings from this study suggest that every case of type III Monteggia fracture-dislocation with decreased or absent function of muscles innervated by PIN and an irreducible radial head in children should be viewed as an indication for immediate surgical exploration of the involved nerve to exclude a potential PIN entrapment.