Joint Compression Is Equivalent when Varying Order of Implant Placement During Equine Proximal Interphalangeal Joint Arthrodesis Using Locking Compression Plate Fixation with Two Transarticular Lag Screws. Farrell AM, Tatarniuk D, Kersh K, Troy J. Iowa State University, Ames, IA.
Determine if altering the order in which implants are tightened can result in different joint compression achieved during equine pastern arthrodesis with a 3-hole locking compression plate with two transarticular lag screws. Investigate whether joint compression differs when tightening transarticular lag screws initially versus tightening of the cortical bone screw placed in load through the bone plate first. Sixteen cadaver limbs were placed into two groups. Pastern arthrodesis was performed with a 3-hole LCP and two abaxial transarticular screws placed in lag fashion for all constructs. Pressure sensitive film was placed in the joint prior to implant placement to quantify compression achieved. In group A, tightening of the single screw in the LCP occurred prior to tightening of the transarticular lag screws. In group B, the transarticular lag screws were tightened prior to the single screw in the LCP. The mean maximum pressure for the dorsal joint surface in group A was 7.2 MPa (± 1.2) and 8.3 MPa (± 1.4) for group B. The mean maximum pressure for the palmar/plantar joint surface in group A was 6.9 MPa (± 1.9) and 7.9 MPa (± 0.8) in group B. There was no statistically significant difference between maximum pressure, average pressure, total area of compression or force measured between groups. Small sample size, type II error possible. A significant difference in joint compression was not identified when varying order of implant placement during standard equine pastern arthrodesis