A modified technique for radiographic measurement of the tibial plateau angle in dogs

This prospective study was aimed at testing a modified method for the measurement of the tibial plateau angle on radiographs of the stifle joint and the proximal part of the tibia. Forty-four stifle joints of 32 client-owned dogs were included in this study. Dogs were presented for hindlimb lameness and suspected cranial cruciate ligament rupture. The diagnostic procedures included radiographic examination. The mediolateral projection of the stifle joint including the tibia and the tarsal joint was used in this study. We tested the most widely used gold standard method as well as three additional methods for tibial plateau angle measurement on each joint. The tibial plateau angle, the positioning of the stifle joint and the presence of osteoarthrosis were recorded. Only 29 (66%) joints had correct position on the radiograph and were used for further study. Repeated-measures ANOVA identified significant differences in mean tibial plateau angle between the different measuring methods. Dunnett's post-hoc test identified a significant difference between the TA-2 and TA-2i methods and TA-0. No significant differences in tibial plateau angle were identified between joints with and without osteoarthrosis. The positioning of the limb significantly influenced the tibial plateau angle. One of the modified methods was found to not differ significantly from the gold standard method; thus, it can be recommended for further testing.