External fixation of fractures of the distal radius: A randomized comparison of the Hoffman compact II non-bridging fixator and the Dynawrist fixator in 75 patients followed for 1 year

Background and purpose External fixators allowing movement during fracture healing are commonly used for treatment of unstable distal radius fractures. The dynamic Dynawrist fixator with the distal pins in metacarpal bone may avoid fixation problems in comminuted fractures and may reduce the risk of nerve injury. We compared anatomical and functional outcome for the well-established Hoffmann compact II non-bridging fixator and for the Dynawrist fixator. Patients and methods 75 patients with unstable distal radius fractures were randomized to treatment with either the Hoffman compact II fixator (the H-group) or the Dynawrist fixator (the D-group). Anatomical and functional variables were recorded preoperatively, postoperatively, and at 6, 12, 24, and 52 weeks. Pain was assessed using the VAS score and function was assessed using DASH score. Results Postoperatively, radial tilt, inclination, and radial length all improved statistically significantly in both groups. At time of removal of the fixators, the H group had superior volar radial tilt. At the 52-week follow-up, there were no statistically significant differences between the groups regarding anatomical variables. At 6 weeks, flexion was greater in the D group but at 12, 24, and 52 weeks flexion was similar in the two groups, as were the other wrist and forearm movements. There were no statistically significant differences between the groups according to VAS and DASH scores. 3 nerve injuries occurred in the H group and 1 in the D group (p = 0.4), all of which were transient. Interpretation The Dynawrist bridging but dynamic fixator gives radiographic and functional outcome similar to that of the Hoffman II compact non-bridging fixator.