Radiographic measurement of canine tibial angles in the sagittal plane

Abstract

Objective To describe a method for radiographic measurement of the mechanical joint angles of the tibia in the sagittal plane and report reference ranges for a population of dogs with cranial cruciate ligament disease, and specifically for Labrador Retrievers. Study Design Retrospective evaluation of radiographs. Animals Canine tibia (n=150) of dogs evaluated for cranial cruciate ligament disease; 104 tibiae were from Labrador Retrievers, 46 tibiae were from other medium- to large-breed dogs. Methods Medial-lateral radiographs were used to establish anatomic landmarks and measure the mechanical cranial distal tibial angle (mCrDTA) and mechanical caudal proximal tibial angle (mCaPTA). Results For all tibiae mean mCrDTA was 81.6°and mCaPTA, 63.6°. For Labrador Retriever tibiae mean mCrDTA was 81.7°and mCaPTA, 63.8°. For non-Labradors, means mCrDTA was 81.5°and mCaPTA, 63°. Labrador Retrievers were significantly younger than non-Labradors in our study population. No significant differences were noted between Labrador Retrievers and non-Labradors for mCrDTA or mCaPTA and correlations between mCrDTA and mCaPTA were neither strong nor significant. Conclusion A method was established for radiographic measurement of mechanical joint angles of the canine tibia in the sagittal plane. Reference ranges are reported for a population of Labrador Retrievers and a population of non-Labradors with cranial cruciate ligament disease. Clinical Relevance Measurement method and reference ranges provided for mechanical tibial angles may be used to aid in diagnosis, surgical planning, and postoperative critique for hindlimb angular deformities. © Copyright 2008 by The American College of Veterinary Surgeons.