The value of computed tomography in detecting distal radioulnar joint instability after a distal radius fracture

This study evaluated the value of computed tomography scans for the diagnosis of distal radioulnar joint instability. A total of 46 patients, conservatively treated for a unilateral distal radius fracture, were evaluated. Clinical instability was tested using the stress test and clunk test. A computed tomography scan of both wrists was performed in pronation and supination. Two independent observers reviewed the computed tomography scans using: the radioulnar line, subluxation ratio, epicentre and radioulnar ratio methods. Radiological distal radioulnar joint instability was assessed by comparing the measurements of the injured wrist with those of the contralateral uninjured wrists. A total of 22 patients had clinical instability of whom 12 suffered from pain in the injured wrist. Distal radioulnar joint instability was diagnosed on computed tomography in 29 patients. Reliability analysis between clinical and radiological evaluations showed at best moderate, but generally poor agreement. The diagnostic ability of computed tomography for identifying distal radioulnar joint instability seems limited. Level of evidence: IV