Role of the Pronator Quadratus in Distal Radius Fractures

Nonunion is an extremely rare complication in distal radius fractures and is most likely to occur in patients with conditions such as diabetes, peripheral vascular disease, or alcoholism. Diagnosis of nonunion is based on the absence of radiographic signs of union at 6 months. Treatment should be individualized but options are reconstructive procedures or wrist arthrodesis. In volar plating and often by the fracture injury itself, the complete pronator quadratus is stripped off the volar radius. Thus, the intraosseous collateral circulation must be sufficient for clinical healing. Any operative approach to the distal radius fracture should not compromise both volar radial and the dorsoulnar arteries. While the branches to the pronator quadratus must be sacrificed in a palmar approach, the distal perforator can and should be spared. This is true even in the flexor carpi radialis extended approach. In distal radius fractures, when the normal outward flow of blood through the cortex is blocked, the periosteal arterioles have more ability than medullary arterioles to function and proliferate.