Radial nerve palsy is a fairly common complication of fracture of the humerus. We know that if axonal continuity is not restored within a reasonable period of time, motor end plates and muscle atrophy, distal segments constrict, and sensory reception is substantially less than it was before the injury. So in cases of humeral shaft nonunion associated with complete, old radial nerve palsy, the nerve should be explored with surgical treatment becoming necessary. PURPOSE: The purpose of this study is to compare the results of primary and secondary radial nerve palsy and to investigate the influence of age, delay in nerve surgery, and length of nerve defect on the results of nerve surgery in humeral shaft nonunion associated with complete, old radial nerve palsy.

From March 1985 to March 1996, 32 cases who had complete radial nerve palsy associated with humeral shaft nonunion were treated by various surgical treatments, such as neurolysis or nerve graft for the injured nerve. The ages of the patients studied ranged from 12 to 66 years (average 38.3 years). The interval between operation or trauma that caused radial nerve palsy and nerve surgery ranged from 6 to 23 months (average 10.8 months). The cause of radial nerve palsy were initial trauma in 18 cases and operations for fracture in 14 cases. The practical cause of radial nerve palsy were found by surgical exploration: 13 cases were severe atrophy and adhesion of nerve by surrounding scar tissue, 15 cases were cross section of nerve and 4 cases were entrapment between the site of fracture or by DCP plate.

The overall recovery rate of radial nerve palsy was 56.3%.

In the author's experience, the amount of nerve tissue lost and delayed time of surgery causes a more unfavorable prognosis. Early surgery is recommended for radial nerve palsy associated with humeral shaft nonunion.