Background: It is generally agreed that a period of observation is appropriate for primary radial nerve palsy associated with humeral shaft fractures. There is no consensus, however, with regard to secondary radial nerve palsy, particularly when it is iatrogenic. Most texts state that surgical exploration is indicated for nerve palsy that occurs after fracture manipulation, but our experience suggests that it is not necessary for radial nerve palsy developing after operative management of humeral shaft fractures.
Methods: A total of 707 humerus shaft fractures were treated operatively at our two hospitals over a 10-year period. Of these, 30 patients sustained iatrogenic radial nerve palsy. Another 16 cases were referred to us with adequate documentation from other institutions. No recognized intraoperative injuries to the radial nerve were recorded in any case.
Results: Of the 46 patients, 21 were female and 25 were male. The median age was 40 years (range, 19-75 years). A total of 39 patients had been treated with dynamic compression plates, 3 with a rigid interlocking intramedullary nail, and 4 with Ender nails. All fractures were diaphyseal, at the middle or distal third level. At the discretion of the surgeon, five cases were surgically explored. In all five cases the radial nerve was in continuity and no macroscopic lesions were noted. All cases eventually recovered grade 4 of 5 muscle strength or better. The median time to the beginning of clinical recovery was 16 weeks (range, 5-30 weeks).
Conclusions: The timing and pattern of radial nerve recovery in this situation was similar to that seen in primary radial nerve palsy. There appears to be no advantage to early exploration of the radial nerve. In the absence of obviously misplaced instrumentation or fracture displacement, we treat it like a primary palsy and recommend observation for a minimum of 4 months before exploration.