Martineau, P A, MD, Waitayawinyu, T, MD, Malone, K J, MD, Hanel, D P, MD, Trumble, T. E., M.D.

The Journal of Hand Surgery, 33(6), 827–834

Purpose: The goal of this study was to determine whether locking screws or smooth locking pegs optimize fixation of AO C3 intra-articular distal radius fractures. A secondary goal was to determine which combinations of locking screws and smooth locking pegs influence construct stability

Methods: In anatomic radius models, AO C3 intra-articular distal radius fractures were fixed using volar locking plates. For the first part, 16 specimens were randmized to receive either 2 locking screws or 2 smooth locking pegs in each of the 3 paris of holes in theplate. For the second part, 30 specimen were randomized to recieve any 4 combinations of locking screws and smooth locking pegs in each of the 3 pairs of holes. Axial loading to failure was applied

Results: Constructs consisting of 4 smooth locking pegs within the lunate fragment were significantly weaker than constructs with 4 locking screws (means 626 N vs 981 N, respectively). Constructs with smooth locking pegs in the ulnar positions of the lunate fragment were weaker than with locking screws in these positions (means 737 N vs 977 N, respectively). Locking screws in the subchondral position of the lunate fragment were stronger than smooth locking pegs in these positions (means 1,227 N vs (34 N, respectively) and anyother combination (means 1,227 N vs 942 N, respectively).

Conclusions: Use of locking screws as oppsed to smooth locking pegs for AO C3 intra-articular distal radius fractures, particularly subchondral and in the ulnar side of the lunate fragement, optimizes construct stability. THis may have implications on postoperative rehabilitiation protocols and may limit costs related to use of volar locking plates. (J Hand surg 2008; 33A:827-834. Copyright 2008 by the American Soceity for Surgery of the Hand. All rights reserved)
Key words: Distal Radius fracture, locking plate, volar plate