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Failure Mode and Bending Moment of Canine Pancarpal Arthrodesis Constructs Stabilized with Two Different Implant Systems

2007; Wiley; Volume: 36; Issue: 8 Linguagem: Inglês

10.1111/j.1532-950x.2007.00326.x

1532-950X

Fred A. Wininger, Amy S. Kapatkin, Alex Radin, Frances S. Shofer, Gail K. Smith,

Foot and Ankle Surgery

To compare failure mode and bending moment of a canine pancarpal arthrodesis construct using either a 2.7 mm/3.5 mm hybrid dynamic compression plate (HDCP) or a 3.5 mm dynamic compression plate (DCP).Paired in vitro biomechanical testing of canine pancarpal arthrodesis constructs stabilized with either a 2.7/3.5 HDCP or 3.5 DCP.Paired cadaveric canine antebrachii (n=5).Pancarpal arthrodesis constructs were loaded to failure (point of maximum load) in 4-point bending using a materials-testing machine. Using this point of failure, bending moments were calculated from system variables for each construct and the 2 plating systems compared using a paired t-test. To examine the relationship between metacarpal diameter and screw diameter failure loads, linear regression was used and Pearson' correlation coefficient was calculated. Significance was set at P<.05.HDCP failed at higher loads than DCP for 9 of 10 constructs. The absolute difference in failure rates between the 2 plates was 0.552+/-0.182 N m, P=.0144 (95% confidence interval: -0.58 to 1.68). This is an 8.1% mean difference in bending strength. There was a significant linear correlation r=0.74 (P-slope=.014) and 0.8 (P-slope=.006) between metacarpal diameter and failure loads for the HDCP and 3.5 DCP, respectively.There was a small but significant difference between bending moment at failure between 2.7/3.5 HDCP and 3.5 DCP constructs; however, the difference may not be clinically evident in all patients.The 2.7/3.5 HDCP has physical and mechanical properties making it a more desirable plate for pancarpal arthrodesis.