Volar hook plate stabilization of volar marginal fragments in intra-articular distal radius fractures.

Background: In the setting of intra-articular distal radius fractures, the volar lunate facet (VLF) is the only articular segment that resists volar carpal subluxation. So, it is important to achieve a stable fixation of this key fragment. The VLF, when small (also called as volar marginal fragment, VMF) is located distal to the watershed line making fixation with the conventional volar locking plates difficult or impossible.

Methods: 18 patients with either an AO: 2R3B3 or a C3 fracture consisting of a VMF underwent surgical repair through a volar approach. The VMF was stabilised using a anatomical volar hook plate. Remaining fracture components were stabilised using 2.4/ 2.0 mm locked plates. Fracture healing, ability of the hook plate to maintain reduction of the VMF and complications were assessed during follow up. Functional outcome was evaluated using Mayo score and patient rated wrist evaluation questionnaires.

Results: All fractures united at follow up. Reduction of the VMF was maintained through healing with a stable radiocarpal and distal radioulnar joint. The mean flexion - extension wrist arc was 105° ± 10.2° The mean grip strength reached 74.6 ± 6% of the opposite side. The mean Mayo wrist score was 75 ± 5.3 and the mean patient rated wrist evaluation (PRWE) score was 15.2 ± 4.3 indicating recovery of wrist function.

Conclusion: It is important to identify VMFs in intra-articular distal radius fractures. Anatomically designed volar hook plate achieves excellent low-profile stable fixation of this key fragment to allow early mobilisation without fearing loss of reduction and volar carpal subluxation.