33rd Annual Scientific Meeting proceedings

Introduction
Methods used to achieve interfragmentary compression during tibial plateau leveling osteotomy (TPLO) vary between surgeons. This study aims to characterise interfragmentary compression, using different compression methods.

Materials and Methods
TPLO was performed in twenty tibia models (Sawbones, Vashon, Washington, USA) using 3D-printed guides for standardization. Interfragmentary compression was measured using pressure-sensitive film (Prescale, Fujifilm, Atherstone, United Kingdom). Seven compression methods were tested: (1) Kern forceps clamping the cranio-distal aspect of the TPLO-plate to the caudal aspect of the tibia (K); (2) using the distal TPLO-plate combi-hole (P); (3) pointed bone reduction forceps engaging the proximal bone fragment and the cranial aspect of the tibia (F); (4) K+P; (5) K+F; (6) F+P; (7) K+F+P. Five measurements were obtained for each method, and each bone model was used for two measurements (single method, +/- plate). The interfragmentary surface was digitalized and divided into quadrants for standardisation and pixel density calculation: (Q1: cranio-medial; Q2: cranio-lateral; Q3: caudo-medial;Q4:caudo-lateral). One-way anova and post-hoc-tests were used for data analysis.

Results
Mean pressures per quadrant differed significantly between methods (p<0.001). Methods K, F, and P produced cranial, lateral, and caudal compression, respectively. Method-K resulted in loss of caudal compression (p<0.001). Method F+P provided the most even distribution of high interfragmentary compression forces. The addition of method K to this construct (K+F+P) marginally increased cranial compression (p=0.189 for Q1; p<0.001 for Q2), but reduced compression caudally (p<0.001).

Discussion/Conclusions
Method F+P provided superior interfragmentary compression. If method K is used, then combined use with method F+P is recommended.