Comparison of cranial vs. medial minimally invasive plate osteosynthesis applications for the stabilization of simulated radius and ulna fractures in dog cadavers

Abstract

Background: Minimally invasive plate osteosynthesis (MIPO) is an emerging fracture management modality in small animal orthopedics. Although cranial plate application has been consistently advocated when performing radial MIPO, medial plating affords several purported advantages including improved screw purchase through the wider medial-to-lateral dimension of the radius, the potential to use smaller plates allowing more screws per unit length, and avoidance of extensor tendons which can complicate cranial plate placement in distal diaphyseal or metaphyseal fractures. Aim: To compare cranial verses medial MIPO applications for the stabilization of diaphyseal radius and ulna fractures in dog cadavers. Methods: Simulated bilateral antebrachial fractures were stabilized with cranial MIPO on one forelimb and medial MIPO on the contralateral limb, facilitated by a 2-ring circular fixator construct. Procedure times and ease, number of fluoroscopic images obtained, and post-procedural frontal and sagittal alignment and radial length, were compared between plating groups. The ease of construct placement, fracture reduction, radial approach, and plate application, were subjectively scored 1-5 for each procedure. Paired t tests were performed to identify significant differences (P<0.05) between the two plating groups. Results: There was no difference in total or incremental procedural times, subjective ease scores, or number of fluoroscopic images obtained between plating groups. Both plating groups had comparable post-procedural frontal and sagittal plane alignment. There was a significant difference between plating groups for final radial length (P=0.004) and change in radial length compared to the intact radii, (P=0.002). Medial plated radii measured longer than cranial plated radii. Conclusion: The only outcome measure significantly different between plating groups was post-procedural radial length. The change in length compared to intact radii was <1%, regardless of the plating group, and unlikely to be clinically relevant.