Core Decompression of the Equine Navicular Bone: An In Vitro Biomechanical Study

Florien Jenner Dr med vet, Diplomate ACVS & ECVS, Carl Kirker-Head MA, Vet MB, Diplomate ACVS & ECVS
Veterinary Surgery
February 2011

Objective: To determine the effect of core decompression surgery and bone mineral density (BMD) on the mechanical properties of equine navicular bones.

Study Design: Experimental, in vitro study.

Sample Population: Fore limb navicular bones (n=36 pairs) from sound 2–5-year-old horses with no radiographic abnormalities of the distal aspect of the forelimbs.

Methods: Navicular BMD was measured using dual energy X-ray absorptiometry. One randomly assigned navicular bone from each pair served as control. The contralateral test specimen was allocated to 1 of 6 treatment groups defined by drill bit size (3.2 versus 2.5 mm diameter) and by the number of drill channels (1, 2, or 3) created in the proximal border of the bone. Bones were then tested until failure in 3-point bending. Data were statistically analyzed using ANOVA and regression analysis.

Results: There were significant (P<.001) positive correlations between BMD and biomechanical data. A significant (P<.001) reduction in breaking strength was noted between intact and drilled bone pairs; however, the diameter and number of decompression channels did not significantly (P>.05) influence the extent of the reduction in mechanical strength.

Conclusion: In vitro core decompression significantly decreases the breaking strength of the equine navicular bone

Large animal: