Association between decreased bone mineral density and severity of distal radial fractures.

BACKGROUND: The role of osteoporosis and osteopenia in the etiology of fractures of the distal part of the radius is well established, but any link between osteoporosis and the severity of the distal radial fracture has not been extensively investigated. The aim of this study was to investigate the association between the degree of osteoporosis and the severity of distal radial fractures.

METHODS: All patients over fifty-five years of age with a low-energy distal radial fracture were offered dual x-ray absorptiometry scanning of the hip. Data on the 137 consecutive patients were collected prospectively. Plain radiographs of the fractured distal part of the radius were assessed for angulation, metaphyseal and articular comminution, carpal malalignment, ulnar variance, AO/OTA group and subgroup classification, early and late displacement, and malunion. Fracture severity was quantified with use of previously published algorithms for calculating the probability of early and late displacement, late carpal malalignment, and malunion. These severity scores were correlated with the dual x-ray absorptiometry T-scores, which represent the number of standard deviations by which the measured bone density differs from the mean value in healthy controls.

RESULTS: There was a significant linear correlation between increasingly negative T-scores and increasing likelihood of early instability, late carpal malalignment, and malunion. Patients with osteoporosis (a T-score of less than -2.5) had a 43% probability of having early instability, a 39% probability of having late carpal malalignment, and a 66% probability of having malunion. Patients with osteopenia (a T-score of more than -2.5 but less than -1) had a 35% probability of having early instability, a 31% probability of having late carpal malalignment, and a 56% probability of having malunion. This compared with a 28% probability of early instability, a 25% probability of late carpal malalignment, and a 48% probability of malunion in patients with normal bone mineral density (a T-score of more than -1).

CONCLUSIONS: There is a definite correlation between bone mineral density and the severity of distal radial fractures.