27 Within- and between-session reliability of the Tekscan™ Hoof System with a glue-on shoe

Abstract

A current focus in equine research is to utilize technology which minimizes the subjective nature of gait and lameness analysis. One such technology is the Tekscan Hoof System, which can measure the force and area of a step while an animal is in motion. The objective of this study was to determine the reliability of the Tekscan Hoof System to measure force and area in 2 different sessions, and recordings within each of those sessions. Four mature Standardbred geldings from the MSU Horse Teaching and Research Center were exercised with Tekscan Hoof System sensors secured by a glue-on shoe (Sound Horse Technologies) to their front hooves. Horses were each exercised in AM and PM sessions. In both the AM and PM sessions, horses walked for 3 recordings of at least 10 steps and trotted for 3 recordings of at least 10 steps. The F-Scan research software (version 6.85) was utilized to analyze and export step data. Session differences were calculated with a MIXED procedure in SAS 9.4, with fixed effects of recording nested within session, gait, horse, and leg. Within- and between-session reliability was assessed in SPSS using Intraclass Correlation Coefficients (ICC(3,k)) and 95% confidence intervals (CI). Force and area in the AM recordings were 30% and 23% (respectively) greater than the PM recordings ( P < 0.0001). Between AM and PM sessions, ICC for the walk had good to excellent reliability for force (0.959; 0.797 – 0.992) and moderate to excellent reliability for area (0.907; 0.537 – 0.981); reliability at the trot was excellent for force (0.982, 0.911–0.996) and poor to excellent for area (0.897; 0.486–0.979). Within the AM and PM sessions, there were no significant differences in force or area between recordings (all P < 0.40). Within the AM and PM sessions, reliability was good to excellent at both walk and trot for force (ICCs ≥0.962; 0.817 – 0.999) and area (ICCs ≥0.942; 0.711 – 0.998). Force and area measurements were lower in the PM session, potentially due to sensel failure caused by exposure to moisture and organic materials. This phenomenon of decreased force and area was not seen within the AM or PM sessions, suggesting that prolonged exposure to moisture and organic matter between sessions may have caused decreased reliability. The Tekscan Hoof System has been found to have good to excellent reliability within a session when used with a glue-on shoe, but caution should be taken when comparing between sessions given the large 95% CI. When used in a research or clinical setting, recordings should be taken within one session for improved reliability.