Quantification of radial torsion angle with computerized tomography: a clinical study

Our objective is to assess the utility of the radial torsion angle (RTA) as described by Bindra et al. in the clinical setting among patients with previous distal radial fractures compared to normal controls [4]. We hypothesize that the side-to-side RTA difference will be increased in subjects with previous forearm fracture as compared to normal subjects. Nineteen patients with a history of distal radial fractures and five normal subjects underwent bilateral upper extremity computerized tomography (CT) scans between 1999 and 2006. The radial torsion angle and the side-to-side difference were calculated by two radiologists. Correlation was made between the RTA and the patient's forearm range of motion (ROM). Mean patient age was 37.8 ± 14.2 years. Mean radial torsion angle was 49.3 ± 22.4 degrees in the affected side and 36.7 ± 13.8 degrees in the unaffected side (p = 0.005). Mean side-to-side RTA was 18.4 ± 10 degrees in the cases versus 3.0 ± 1.41 degrees in normal subjects (p < 0.0001). Kappa coefficient for the side-to-side RTA differences was 0.62 (good agreement). Eighteen out of the 19 patients underwent surgery, ten of which were osteotomies. There was a statistically significant increase in side-to-side difference in the RTA among patients compared to controls.