The effect on supination-pronation of angular malalignment of fractures of both bones of the forearm

Ten fresh human upper-extremity cadaver specimens were tested for the effect of residual angulation from simulated fractures of both bones of the forearm on the potential for range of rotation of the forearm and for limitations of pronation and supination specifically. Ten and 20-degree angulations for the radius and ulna, such as might be encountered in all reasonable clinical situations, were tested. Little significant loss of forearm rotation resulted from angulations of 10 degrees in any direction. With 20 degrees of angulation, there was statistically significant and functionally important loss of forearm rotation.

A residual angulation of 10 degrees in mid-shaft fractures of the radius, ulna, or both bones of the forearm will not limit forearm rotation anatomically. Loss in the range of rotation can be expected with residual angeles of 20 degrees or more.