The in vitro comparison of monotonic and cyclic mechanical properties of equine proximal interphalangeal joint arthrodeses stabilized using an open or closed technique and application of 2 abaxial transarticular lag screws combined with either an axial 4.5mm narrow 3-hole LC-DCP with 5.5mm cortical screws a 4.5mm narrow 3-hole LCP with 5.0mm locking screws. Limbs were tested for cyclic fatigue at 20,0000cycles and then in single-cycle to failure under 3-point, dorsopalmar bending. There were no significant differences in stiffness and single-cycle to failure values between the LCP and LC-DCP constructs, with or without PIPJ collateral ligament transaction. There was no interaction between the open and closed techniques, nor between plate types on force or stiffness at failure.