[Multidirectional screw fixation in the treatment of distal radius fractures using angle-stable plates]

Intra-articular fractures of the distal radius are treated predominantly by open reduction and internal fixation with various types of angle-stable plates. In this study we compare functional and radiographic outcomes in patients with intra-articular distal radius fractures treated with either angle-stable plates with rigid-direction screw insertion or multidirectional angle-stable plates.

The LCP group included 37 patients with an average age of 50 years (range 20-81 years) who were treated using angle-stable plates with rigid-direction screw insertion (LCP, Synthes). The APTUS group comprising 41 patients with an average age of 48.9 years (range 22-77 years) was treated by angle-stable implants in which screws can pivot freely in all directions (Aptus, Medartis). There was no significant difference between the groups in relation to fracture severity, age or other relevant characteristics. In all cases we used the volar approach. The final evaluation of treatment outcome was made at 12 months after surgery. We measured the range of wrist motion and hand grip strength, and compared the values with those obtained in the contralateral wrist. The results evaluated on the scoring systems of Gartland and Werley and of Castaing, and the DASH score were compared between the groups. The findings on radiographs were compared with the anatomical standard in the distal radius region. RESULTS In the LCP group, the average values, as compared with the contralateral side, were as follows: volar flexion, 84.2 %; dorsal flexion, 82.4 %; radial deviation, 83.2 %; ulnar deviation, 89.1 %; pronation, 98.6 %; supination, 97.4 %. In the APTUS group, the values in comparison with the other wrist were: volar flexion, 84.1 %; dorsal flexion, 91.8 %; radial deviation, 95.1 %; ulnar deviation, 92.8 %; pronation, 99.0 %; supination, 98.1 %. The values statistically comparable with the contralateral side were those in pronation, supination and hand grip strength in both groups. In addition, in the APTUS group, the values corresponding to the healthy wrist function were achieved in both radial and ulnar deviation. There were no differences in the values based on the scoring systems between the LCP and APTUS groups. As for the radiographic parameters, only the reconstruction of radial length was optimal. The other parameters differed from the anatomical standard. However, all patients met the criteria of successful healing of a distal radius fracture. Secondary fragment displacement during healing was recorded in two patients of the LCP group and in one of the APTUS group. Transient irritation of the median nerve was observed in five LCP group patients and in only one APTUS group patient. One patient in each group had an extensor tendon rupture. Reflex sympathetic dystrophy syndrome was diagnosed in two LCP group patients and in three APTUS group patients. DISCUSSION The surgical treatment of complex fractures of the distal radius using the angle-stable implants has generally achieved very good functional and radiographic outcomes with a low rate of complications. In the APTUS group, in contrast to the LCP group, the extent of radial and ulnar deviation corresponded to that found in the healthy wrist. The reason was a low-profile design of the plate and the screws, and the system with multidirectional angle-stable screws. The fewer cases of median nerve irritation in the APTUS group can be explained by the use of a different operative approach reducing the risk of direct mechanical nerve injury. In contrast to other authors, flexor tendon ruptures were not recorded in our groups. CONCLUSIONS The treatment of distal radius fractures by the angle-stable locking plate system from the volar approach achieved comparable functional and radiographic outcomes with both rigid-direction screw insertion and multidirectional screw insertion.