Carpal malalignment in malunion of the distal radius and the effect of corrective osteotomy.

Introduction Malunions of the distal radius often induce carpal malalignment. Two different types can be distinguished: an adaptive midcarpal malalignment (so-called CIA wrist: carpal instability, adaptive) and a radiocarpal malalignment (dorsal translation of the whole carpus). The effect of distal radial osteotomy on the carpal alignment has hardly been studied. Material and Methods 31 wrists in 31 patients (mean age 44 years) with malunion of the distal radius after a Colles fracture were treated with a corrective osteotomy. The patients were divided on basis of effective radio-lunate flexion (ERLF) in the two patterns of carpal malalignment. The radiographic changes were evaluated. Results There were 20 patients with midcarpal malalignment (ERLF ≤ 25°) and 11 with radiocarpal malalignment (ERLF > 25°). There was a correction of radial tilt and ulnar variance in both groups. There was a significant improvement of the carpal alignment in the midcarpal malalignment group, up to normal parameters. Neither age nor delay between fracture and osteotomy correlated. In the radiocarpal malalignment group a significant effect on the ERLF was observed. In the patients with dorsal plating 70% of the hardware had to be removed. Conclusion Distal radial osteotomy is a reliable technique for correction of the deformity at the distal end of the radius and carpal malalignment.