Evaluation of an in-shoe pressure measurement system in horses

Objective-To develop an objective, accurate method for quantifying forelimb ground reaction forces in horses by adapting a human in-shoe pressure meas urement system and determine the reliability of the system for shed and uns hod horses. Animals-6 adult Thoroughbreds. Procedure-Horses were instrumented with a human in-shoe pressure measuremen t system and evaluated at a trot (3 m/s) on a motorized treadmill. Maximum force, stance time, and peak contact area were evaluated for shed and unsho d horses. Three trials were performed for shed and unshod horses, and diffe rences in the measured values were examined with a mixed model ANOVA for re peated measures. Sensor accuracy was evaluated by correlating measured vari ables to clinically observed lameness and by a variance component analysis. Results-4 of 6 horses were determined to be lame in a forelimb on the basis of clinical examination and measured values from the system. No significan t differences were observed between shed and unshod horses for maximum forc e and stance time. A significant decrease in peak contact area was observed for shed and unshod horses at each successive trial. Maximum force measure ments provided the highest correlation for detecting lameness (r = 0.91, sh ed horses; r = 1.0, unshod horses). A variance component analysis revealed that 3 trials provided a variance of 35.35 kg for maximum force (+/- 5.78% accuracy), 0.007 seconds for stance time (+/- 2.5% accuracy), and 8.58 cm(2 ) for peak contact area (+/- 11.95% accuracy). Conclusions and Clinical Relevance-The in-shoe pressure measurement system provides an accurate, objective, and effective method to evaluate lameness in horses.