A Comparison of Dynamic Compression Plates and Locking Compression Plates Using Cantilever Bending in a Canine Ilial Fracture Model

Abstract

Pelvic fractures account for approximately one quarter of all fractures in small animals of which 18-46% are ilial fractures. The most common treatment of ilial fractures is lateral plating with the most common complication being implant failure usually due to screw loosening from the cranial ilial segment. The high incidence of screw loosening has been attributed to poor quality bone in the cranial ilial segment. Ten pelves were harvested from healthy dogs euthanized for reasons unrelated to this study and divided into two groups. A transverse osteotomy was performed and stabilized with either a 6-hole Dynamic Compression Plate applied in compression or a 6-hole Locking Compression Plate. Pelves were tested in cantilever bending to failure and construct stiffness, yield load, ultimate load at failure, displacement at failure, and mode of failure compared. The mean stiffness (N/mm) of tested DCP constructs was 192 (95% CI 121-264) and of LCP constructs was 224 (95% CI 152 - 295) and mean yield load (N) of DCP constructs was 900 (95% CI 649-1151) and of LCP constructs was 984 (95% CI 733-1235). Observed locking plate construct performance did appear superior to non-locking constructs, but no significant statistical differences were found between the constructs with respect to mode of failure, stiffness, displacement at failure, yield load or ultimate load at failure. Our study suggests that given the limited number of samples there is no difference between DCP and LCP construct performance in vitro acute failure testing.