[Temporary external fixation in the correction of non articular mal-unions of the distal radius].

PURPOSE OF THE STUDY: The authors reviewed 21 cases of extra articular malunions of the distal radius treated by osteotomy, temporary external fixation, then osteosynthesis. Two groups were studied: Group A of 14 patients with dorsal tilt of the distal radius and Group B of 7 patients with palmar tilt of the distal radius. Mean follow-up of this series was 69 months ranged from 12 to 109 months.

MATERIAL AND METHODS: In Group A, after exposure of the distal radius through a dorsal approach, the site of osteotomy, proximal to the distal radio-ulnar joint, was determined by fluoroscopy. The angular correction was done by progressive opening using a small external fixator. After checking on the correction, the bone graft was harvested 7 times on the radius as described by Watson et Castle, 7 times on the iliac crest. Bone fixation was done by two K-wires and a cast for 8 to 10 weeks. Three Sauvé-Kapandji procedures was done at the same time. In Group B, the approach was palmar, extended distally to open the carpal tunnel. The distraction was done with a distal T-shaped external fixator. The bone graft was always harvested on the iliac crest. Bone fixation was done with a T-shaped palmar plate. Two Sauvé-Kapandji procedures was done at the same time.

RESULTS: Group A: Flexion-extension arc was improved of 15.5 p. 100, pronation-supination of 83.7 p. 100 and grip strength of 80 per cent of the pre-operative values. Radiological evaluation showed good correction except one case of undercorrection of the dorsal tilt (-7 degrees) and one case of undercorrection of the radial inclination (+6 degrees). The distal radio-ulnar index was measured at the mean of 0mm postoperatively compared to +5 mm pre-operatively. One patient developed a postoperative radiocarpal arthritis. Group B: Flexion-extension arc was improved of 96.2 p. 100, pronation-supination of 76.9 p. 100 and grip strength of 108.3 p. 100 of the preoperative values. Radiological evaluation showed good correction except one case of overcorrection of the palmar tilt (-10 degrees) and one case of undercorrection of the radial inclination (+7 degrees). The distal radio-ulnar index was measured at the mean of 0mm postoperatively compared to +7 mm pre-operatively.

DISCUSSION: The functional consequences of malunions of the distal radius have been stressed by others for more than sixty years. Since, many authors have contributed to refine and improve their surgical correction. Several displacements should be taked into account for the preoperative planning. They are sagittal tilt, frontal horizontalisation, shortening, sagittal and frontal translation, and axial rotation. Many types of osteotomies could be done; closing wedge, opening wedge or reorientation. In some cases, an operative procedure of the distal radio-ulnar joint should be done at the same time. We chose an opening-wedge osteotomy and the use of a temporary external fixator to ensure progressive distraction and good adjustment in the correction of angular deformities. In the dorsal tilt group we were satisfied in using on 7 patients a trapezoidal cortico-cancellous bone graft harvested on the radius.

CONCLUSION: The authors would like to stress two points: The technical interest of using a temporary external fixator to adjust the angular correction of the distal radius. The importance of an adequate treatment of distal radius fractures in emergency situation, considering the functional and cosmetic alterations due to malunions and their need for surgical corrections in main instances.