Fixation Strength in Full and Limited Fixation of Osteoporotic Distal Radius Fractures.

Abstract

The purpose of this investigation is to determine whether osteoporotic intra-articular distal radius fractures surgically treated by filling all 7 distal screws of a volar plate will have a higher load to failure than those treated by filling only 4 distal screws. Ten matched pairs of fresh frozen cadaveric forearms were randomized within each pair to be treated by using either all 7 of the distal holes of a volar plate or only 4 distal screws. The distal radius fixation was performed with unicortical screws going to but not through the dorsal cortex, and the most distal screws were placed within 4 mm of the joint surface. An AO C2 type fracture was then created. All specimens were tested cyclically, with an axial load of 60 N, at 3 Hz for 1000 cycles to simulate early postoperative motion. All specimens were subsequently tested to mechanical failure. There were no failures in either group during cyclic testing. There was no difference detected between groups for mean stiffness, yield load, peak load, or load to clinical failure. In both groups, the yield load, peak load, and load to clinical failure were higher than the 60- to 100-N forces encountered during postoperative rehabilitation. There was no difference detected between osteoporotic intra-articular distal radius fractures treated by utilizing all 7 of the distal screws of a volar plate compared with those treated with only 4 distal screws.