Precision and Accuracy of Ground Reaction Force Normalization in a Heterogeneous Population of Dogs
Article first published online: 5 APR 2014
© Copyright 2014 by The American College of Veterinary Surgeons
Volume 43, Issue 4, pages 437–445, May 2014
How to Cite
Krotscheck, U., Todhunter, R. J., Nelson, S. A., Sutter, N. B. and Mohammed, H. O. (2014), Precision and Accuracy of Ground Reaction Force Normalization in a Heterogeneous Population of Dogs. Veterinary Surgery, 43: 437–445. doi: 10.1111/j.1532-950X.2014.12176.x
- Issue published online: 9 MAY 2014
- Article first published online: 5 APR 2014
- Manuscript Accepted: 1 NOV 2012
- Manuscript Received: 30 APR 2012
To determine if currently used ground reaction force (GRF) normalization methods are accurate and precise enough to be used on a single-limb basis.
Prospective clinical trial.
Clinically normal (n = 69) dogs and 40 dogs with unilateral ruptured cranial cruciate ligaments (CCL).
Pelvic limb GRFs of orthopedically normal dogs and those with unilateral ruptured CCL were collected. Normalization methods included none, body weight (BW), withers height (WH), WH and relative velocity (WH*F) and principal component 1 (PC1). Normalization methods were evaluated both by individual GRFs and additively. Binary logistic regression was performed for all normalization methods; sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) calculated. Stepwise backward logistic regression was used; significant values were retained in the final model. P < .05 was significant.
Normalization of contact time (CT) by BW uniformly increased sensitivity, specificity, PPV, NPV, and accuracy. SI was the most accurate at both the walk and trot (accuracy 80–96%). Normalization by BW, WH, and WH*F all achieved similar results. When normalized GRFs were added, the accuracy increased only at the walk.
CT should be normalized to BW. SIs remain the gold standard, if SIs cannot be used, combining GRFs normalized to BW will result in high precision (80%) and high accuracy (89.5%) at the walk. At the trot, normalization by BW, WH and WH*F results in consistent results for the individual GRFs, though not all accuracies are >80%.