Instrumented measurement of in vivo anterior-posterior translation in the canine knee to assess anterior cruciate integrity.

This study was designed to objectively quantify in vivo anterior-posterior canine knee translation relative to anterior cruciate ligament (ACL) integrity. Tibial translation was determined in one knee of 43 crossbreed hounds from radiographs performed while a set anterior and then posterior force was applied to the tibia using a custom designed device. The total (TTT), anterior (ATT), and posterior (PTT) tibial translation were measured (absolute) and normalized to the width of the tibia (normalized). Absolute and normalized TTT was significantly greater in ruptured ACL knees than in partially disrupted (PD) ACL knees, which were significantly greater than in intact ACL knees. ATT and PTT was significantly greater in ruptured ACL knees than in PD or intact ACL knees, which were not significantly different. The sensitivity and specificity of normalized TTT to distinguish knees with intact from PD ACLs were both 100%. Normalized TTT to distinguish knees with PD from ruptured ACLs had a sensitivity and specificity of 100% and 92%, respectively. Intra- and inter-observer intra-class correlation coefficients were 0.84 or higher for all translations. This precise non-invasive technique to assess canine knee translational stability and ACL integrity permits repetitive, objective measurements for diagnostic use and to assess therapeutic intervention efficacy.