Comparison of canine stifle kinematic data collected with three different targeting models.

OBJECTIVE To model the kinematics of the canine stifle in 3 dimensions using the Joint Coordinate System (JCS) and compare the JCS method with linear and segmental models. STUDY DESIGN In vivo biomechanical study. ANIMALS Normal adult mixed breed dogs (n=6). METHODS Dogs had 10 retroreflective markers affixed to the skin on the right pelvic limb. Dogs were walked and trotted 5 times through the calibrated space and the procedure was repeated 5 days later. Sagittal flexion and extension angle waveforms acquired during each trial with all 3 models (JCS, Linear, and Segmental) were produced simultaneously during each gait. The JCS method provided additional internal/external and abduction/adduction angles. Comparison of sagittal flexion and extension angle waveforms was performed with generalized indicator function analysis (GIFA) and Fourier analysis. A normalization procedure was performed. RESULTS Each model provided consistent equivalent sagittal flexion-extension data. The JCS provided consistent additional internal/external and abduction/adduction. Sagittal waveform differences were found between methods and testing days for each dog at a walk and a trot with both GIFA and Fourier analysis. After normalization, differences were less with Fourier analysis and were unaltered with GIFA. CONCLUSIONS Whereas all methods produced similar flexion-extension waveforms, JCS provided additional valuable data. CLINICAL RELEVANCE The JCS model provided sagittal plane flexion/extension data as well as internal/external rotation and abduction/adduction data.