Effect of Plate Type on Tibial Plateau Levelling and Medialization Osteotomy for Treatment of Cranial Cruciate Ligament Rupture and Concomitant Medial Patellar Luxation in Small Breed Dogs: An In Vitro Study

Abstract

Abstract Objective The main aim of this study was to determine the effective magnitude of proximal tibial segment medialization achievable during tibial plateau levelling and medialization osteotomy (TPLO-M) with Fixin 1.9-2.5 mm pre-contoured T plates with three different offsets. Methods In this in vitro study, 36 tibia bone models reconstructed using stereolithography from hindlimb CT scans of a 5 kg dog and a 10 kg dog without orthopaedic disease were used. TPLO-M was performed using plates with three different offsets (2, 4 and 6 mm). Post-osteotomy radiographic and bone models measurements were performed. Results Regardless of patient weight, the +4 mm offset plates provided a translation of 2.93mm (± 0.51) while the +6 mm offset plates provided a translation of 5.03mm (± 0.47). In the 5kg dog bone model group limited bone contact at the osteotomy site was documented when using the +6mm offset plate. Conclusion The +4mm and +6mm offset Fixin plates may be considered for TPLO-M in dogs weighing between 5 and 10 kg. The +6mm offset plate should be used cautiously in dogs weighing less than 10 kg since this plate may result in insufficient postoperative bone apposition at the osteotomy site.