Thoracic Limb Angular Deformity in Chondrodystrophic Dogs: Repeatability of Goniometric Measurement of External Rotation and Carpal Valgus

Objective We aimed to provide repeatable methods for quantifying antebrachial valgus and rotation in dogs with and without complex angular deformities. Thus, we investigated the repeatability of two methods to measure carpal valgus and one method to measure external rotation of the thoracic limb in a standing position. Study Design This was a prospective observer agreement study with a sample of 18 non-chondrodystrophic dogs as baseline and 43 chondrodystrophic dogs. The rotation measurements (ROT), modified valgus measurements (VALG-M), and established carpal valgus measurements (VALG) were done independently by two investigators. Repeatability was assessed with intraclass correlation coefficient (ICC). Results The measured mean (± standard deviation) angles of ROT, VALG-M, and VALG for non-chondrodystrophic dogs were 14 degrees (± 5 degrees), 9 degrees (± 4 degrees), and 4 degrees (± 3 degrees) and 30 degrees (± 13 degrees) and 23 degrees (± 11 degrees) for ROT and VALG-M for chondrodystrophic dogs respectively. In non-chondrodystrophic dogs, ICC was low with mean errors of 1 to 6 degrees, whereas in chondrodystrophic dogs, intra- and intertester ICC was high for ROT and VALG-M with mean errors of 3 to 8 degrees. Conclusion The ROT and VALG-M methods can be used as reliable tools to objectively quantify aspects of thoracic limb alignment for research, clinical, and screening purposes in both non-chondrodystrophic and chondrodystrophic dogs. The mean values of ROT, VALG-M, and VALG can be used as references for non-chondrodystrophic dogs in the standing position.