The currently available 5.5 mm cortex screw with 8 mm head size, used for large animal fracture fixation, is with ratio of 1.45 between them, being outside of the EN ISO standard range (1.75 – 2.00) required for human orthopedic cortical screws.
To compare the biomechanical competency of a new modified 5.5 mm cortex screw with 10 mm head size versus the regular 5.5 mm one in equine medial condylar fracture fixation.
Following creation of complete parasagittal lateral osteotomies in fifteen pairs of equine cadaveric third metacarpal bones, assigned pairwise for fixation with either the modified or the regular cortical screw, maximal insertion torque and load to failure under axial loading were evaluated for each specimen. The modified 5.5 mm cortex screw with larger head of 10 mm size achieved higher insertion torque, was less susceptible to stripping, and seemed to resist higher load to failure compared to the regular 5.5 mm cortex screw with 8 mm head size.
Constant C, Zderic I, Arens D, Pugliese B, Gehweiler D, Gueorguiev-Rüegg B, Zeiter S.Improved biomechanical properties of modified 5.5mm cortex screw with larger head size in an equine lateral condylar fracture model.2021 ACVS surgery summit virtual (oral)