Biomechanical comparison of two plating techniques for fixation of acetabular osteotomies in dogs

Objective-To compare the failure properties of a 5-hole, 2.7-mm curved acet abular plate (AP) to a 5-hole, 3.5-mm reconstruction plate (RP) when applie d to acetabular osteotomies. Study Design-Cadaver study. Animals or Sample Population-Pelves of 8 mature, large-breed dogs. Methods-A 5-hole, 2.7-mm AP and a 5-hole, 3.5-mm RP were contoured and appl ied to the dorsal acetabulum of each pelvis. A central acetabular fracture was simulated after plate application by a transverse osteotomy with a fine saw. Each acetabulum was loaded in a weight-bearing direction A load-defor mation curve was produced for each construct, and biomechanical properties of the AP and RP were compared with the Student's paired t-test. A P value of < .05 was considered significant. Results-For the AP and RP composite respectively, the mean +/- SD maximum l oad to failure was 2,721 +/- 632 N and 2,388 +/- 800 N, the stiffness was 4 .8 +/- 1.8 N/m and 5.3 +/- 1.9 N/m, and the energy absorbed was 15.1 +/- 5. 2 Nm and 16.3 +/- 8.3 Nm. None of these differences was statistically signi ficant. Conclusions-Both fixation techniques provided comparable strength, stiffnes s, and energy absorbed under the loading conditions of this study. Clinical Relevance-Because of the relative ease of application, the 2.7-mm curved AP may be the practical choice for acetabular fracture repair in lar ge dogs. (C) Copyright 1999 by The American College of Veterinary Surgeons.