in vitro biomechanical comparison of the insertion variables and pullout mechanical properties of AO 6.5-mm standard cancellous and 7.3-mm self-tapping, cannulated bone screws in foal femoral bone

• Published in: Veterinary surgery 2004-11, Vol.33 (6), p.691-698
• Main Authors: Johnson, N.L, Galuppo, L.D, Stover, S.M, Taylor, K.T
• Format: Article
• Language: English
• Subjects: Animals; Animals, Newborn; bending strength; Biomechanical Phenomena; bone fractures; Bone Screws - veterinary; Bones; cancellous bone screw; cannulated bone screw; durability; equine; equipment performance; Female; Femoral Fractures - surgery; Femoral Fractures - veterinary; femur; foal; foals; forces; fracture fixation; Fracture Fixation, Intramedullary - methods; Fracture Fixation, Intramedullary - veterinary; horse; Horses; Horses - injuries; Horses - surgery; Legs; loads; Male; mechanical properties; screw pullout; screws; Surgery; surgical equipment; torque; Treatment Outcome; Veterinary services
• ISSN: 0161-3499; 1532-950X
• DOI: 10.1111/j.1532-950x.2004.04093.x

Objective— To compare screw insertion variables and pullout mechanical properties between AO 6.5‐mm cancellous and 7.3‐mm cannulated bone screws in foal femoral bone. Study Design— A paired, in vitro mechanical study. Sample Population— Seven pairs of femora from immature (1–7 months) foals. Methods— The 6.5 cancellous and 7.3‐mm cannulated screws were inserted at standardized proximal and distal metaphyseal, and mid‐diaphyseal locations. Insertion torque, force, and time to drill, tap (6.5‐mm cancellous), guide wire insertion (7.3‐mm cannulated), and screw insertion were measured. Screw pullout properties (yield and failure load, displacement, and energy, and stiffness) were determined from mechanical tests. The effects of screw type and location on insertion variables and pullout properties were assessed with repeated measures ANOVA. Pairwise comparisons were examined with post hoc contrasts. Significance was set at P