The effect of radial osteotomy on the position of the posterior interosseous nerve.

The purpose of this study was to determine whether a radial shaft fracture would decrease the protection provided to the posterior interosseous nerve by the pronation maneuver during posterolateral exploration. The position of the nerve in 14 cadaveric elbows, before and after a radial osteotomy, was determined using CT scans in full supination and full pronation after injection of the nerve with radio-opaque dye. The angle formed by the olecranon, radial head and posterior interosseous nerve, and the distance between the nerve and the most lateral aspect of the radial head were measured.Pronation increased the distance between the lateral radial head and the nerve by a mean of 6.5 mm (range 3.6-10.7). After radial osteotomy, the mean increase was 4.2 mm (range 1.0-8.3), difference 2.3 mm (p = 0.044, 95% CI 0.10 to 3.33). The posterolateral approach requires additional care in the presence of a radial shaft fracture, but pronation is still beneficial.