The radioulnar ratio: A new method of quantifying distal radioulnar joint subluxation

Computed tomography was used to image the distal radioulnar joint (DRUJ) fo r instability. Four methods were used to quantify subluxation of the DRUJ: the Mine criteria, the epicenter method, the congruency method, and a new m ethod called the radioulnar ratio (RUR). Validity of the various methods wa s evaluated in clinical and laboratory situations. Rheumatoid patients with symptomatic DRUJ pathology had significantly more abnormal RUR values (100 % vs 73% [epicenter method] and 88% [Mino criterial). The RUR detected inst ability sooner in a progressive laboratory-induced instability model. The i ntraobserver and interobserver reliability of the RUR was high, with intrac lass correlation coefficients of 0.89 and 0.87, respectively. The RUR demon strated superior performance in the diagnosis of DRUJ subluxation. (J Hand Surg 2001;26A3236-243. Copyright (C) 2001 by the American Society for Surge ry of the Hand.).