Interfragmentary compression in a feline sacroiliac luxation model: biomechanical comparison of cannulated compression headless screws and cortical screws applied in positional or lag fashion.

BACKGROUND: The purpose of this study was to compare the efficacy of cannulated compression headless screws (CCHS) with cortical positional and lag screws in generating interfragmentary compression in a simulated feline sacroiliac luxation fracture (SILF) model. In this ex vivo biomechanical study thirty-six cadavers of adult domestic short-haired cats with simulated unilateral SILF were allocated to three groups. Pressure mapping sensors were inserted into the joint space prior to fracture reduction. The SILF models were stabilized with 2.5 mm CCHS (n = 12), 2.4 mm cortical position (n = 12) or lag screws (n = 12), each spanning 60% of the sacral width. Total force (N), area of compression (mm2) and total pressure (N/mm2) were recorded and compared between the three groups. Pairwise comparison (Dunn for Kruskal-Wallis, Student's t-tests for Fisher's ANOVA) determined post-hoc differences between groups.

RESULTS: Total force (p = 0.23), area of compression (p = 0.62) and total pressure (p = 0.22) did not differ significantly between the three groups.

CONCLUSION: No statistically significant differences in interfragmentary compression were observed among the three screw types under the specific ex vivo static testing conditions used in the feline SILF model. These findings challenge the current recommendation for using compression screws in feline SILF from a biomechanical perspective.