Rotational deformity affects radiographic measurements in distal radius malunion

Abstract

Malunited distal radius fractures are 3D deformities. The preoperative evaluation of the deformity and surgical planning are usually depended on plain radiographic measurements for corrective osteotomies. In most of the cases, the rotational deformity is disregarded in preoperative planning. We aimed to clarify the effect of rotational deformity on radial inclination and dorsal or volar tilt measurements, which are commonly used as radiologic parameters. This study was performed on standard left radius saw bone models. The malunion models were prepared according to AO distal radius fracture classification system in four main and seventeen subgroups. The differences between the mean radial inclination, volar or dorsal tilt measurements performed on plain radiographies and gold standard values were statistically analyzed. Results showed that rotational deformity causes faulty measurements of radial inclination and dorsal tilt on plain radiographies which may be a contributing factor for unsatisfactory clinical results of corrective osteotomy. We suggest 3D preoperative evaluation of the deformity if possible.