Relationship between objective and subjective assessment of limb function in normal dogs with an experimentally induced lameness

Objective To evaluate the relationship between previously used subjective and objective measures of limb function in normal dogs that had an induced lameness. Study Design Prospective, blinded, and induced animal model trial. Animals Normal, adult, and mixed-breed dogs (n=24) weighing 25-35 kg. Methods Force platform gait analysis was collected in all dogs before and after induction of lameness. All gait trials were videotaped; 60 video trials were evaluated by 3 surgeons with practice limited to small animal orthopedics and 3 first year veterinary students in an effort to establish the relationship between subjective and objective measures of lameness. Evaluators were unaware of the force platform data. Results Concordance coefficients were low for all observers and were similar between students and surgeons. These values were further decreased when normal and non-weight bearing trials were removed. Agreement with the force platform data was low even when observers only had to be within ±10% of the ground reaction forces. When repeat trials were evaluated surgeons had a much higher repeatability compared with students. Conclusions Subjective evaluation of the lameness in this study varied greatly between observers and agreed poorly with objective measures of limb function. Clinical Relevance Subjective evaluation of gait should be interpreted cautiously as an outcome measure whether performed from a single or from multiple observers.