The Effect of Distal Radius Fracture Location on Distal Radioulnar Joint Stability: A Cadaveric Study

Abstract

To investigate whether the location of distal radius osteotomy/shortening relative to the radial insertion of the distal interosseous membrane (DIOM) is correlated with distal radioulnar joint (DRUJ) instability. We hypothesized that distal radius osteotomy and shortening proximal to the DIOM insertion would result in increased DRUJ instability because of induced laxity in the DIOM. Osteotomies of the distal radius were performed proximal and distal to the DIOM insertion in 14 fresh-frozen cadaveric specimens. Using a volar plate, 5 conditions were tested: anatomical radius alignment; 2- and 4-mm shortening at the proximal osteotomy site; and 2- and 4-mm shortening at the distal osteotomy site. Basilar ulnar styloid osteotomy was performed to simulate triangular fibrocartilage complex (TFCC) detachment-specimens were tested with the ulnar styloid detached and the ulnar styloid fixed (to restore normal anatomy). The DRUJ stability was quantified using dorsal-volar displacement of the radius in response to 20 N of force using a force-displacement probe in neutral, pronation, and supination. Posttesting specimen dissections assessed DIOM and distal oblique bundle (DOB) anatomy. The DRUJ stability in each experimental condition was compared with a multifactor repeated measures analysis of variance with the specimen treated as the repeated factor. There were no significant differences in dorsal-volar translation of the radius (ie, DRUJ stability) between radial osteotomy/shortening proximal and distal to the DIOM insertion, regardless of forearm rotational position or magnitude of shortening. Five (36%) of the 14 specimens had a DOB present. There was a significant increase in DRUJ instability in the setting of TFCC detachment (via basilar ulnar styloid osteotomy). No difference in DRUJ stability was observed between distal radius osteotomy/shortening proximal and distal to the DIOM radial insertion, regardless of forearm rotation, magnitude of shortening, and/or TFCC detachment. Distal radius osteotomy and shortening did not affect DRUJ stability regardless of location relative to the DIOM insertion.