ABSTRACT
PURPOSE OF THE STUDY: Intra-focal pinning as described by Kapandji in 1976 is generally standard treatment of fractures of the distal radius with posterior displacement. This technique, based on the bench effect of pinning on the posterior and radial cortexes has certain limitations in the event of major posterior comminution. In order to improve stability, other authors have proposed a modification of the Kapandji technique, replacing the lateral intra-focal pin with a direct trans-styloid pin. The purpose of this prospective radiographic study was to determine whether the modified Kapandji method improves the quality of postoperative reduction and provides a gain in stability. MATERIAL AND METHODS: This prospective radiographic study included 85 patients. The first group, composed of 41 patients, was treated with the standard intra-focal pinning using one or two dorsal pins and one lateral pin (group K). The second group of 44 patients was treated with one or two intra-focal pins and one lateral transfocal pin (group KM). The postoperative care was the same for the two groups. Clinical and radiographic assessment (lateral and AP views) was performed at day 21, at day 45 after removal of the pins, and at last follow-up. Two operators working independently from the surgeons measured the orientation of the radial surface on the lateral and AP views and the radioulnar variance at day 0, 21, 45 and last follow-up. RESULTS: Group K included 38 patients, mean age 57 years, and group KM 40 patients, mean age 53 years. Seven patients were lost to follow-up. The two groups were comparable regarding age, gender, type of lesion. The postoperative assessment showed radial inclination of 19.3 degrees on the AP view and 3 degrees on the lateral view with 6.6 degrees radiolulnar variance for the K group. The corresponding values were 22.2 degrees , 5.3 degrees and 12.2 degrees for the KM group. Postoperatively, there was a significant difference between the groups for radial glenoid on the AP view (p=0.004) and radiolulnar variance (p<0.0001) but there were no differences on the lateral view. At day 45 postop, mean values were 17.3 degrees AP and 1.1 degrees lateral for radial inclination and 2.2 degrees for radioulnar variance in the K group with 21 degrees , 4.7 degrees and 10 degrees in the KM group. There was a difference in group K for values measured on day 0 and day 45. There was no significant difference between the values on day 0 and day 45 for the KM group. DISCUSSION AND CONCLUSION: The purpose of this radiological assessment was to evaluate the efficacy of replacing the lateral intra-focal pin with a lateral transfocal pin in terms of primary stability of extra-articular fractures of the distal radius with posterior displacement. The results appear to show that this technique provides more sustained reduction during the first six weeks, particularly concerning radioulnar variance and radial glenoid inclination on the AP view, objectives needed for good clinical outcome. It also enables a notable improvement in postoperative stability while preserving the advantages of an easily reproducible minimally destructive percutaneous technique.
