Commercially available objective gait evaluation systems show good to excellent reliability in horses across hard-surface types and multiple operators

Abstract Objective To evaluate the intrasystem reliability of an AI-based smartphone application Sleip (AI-SPA), the inertial measurement unit (IMU) system Equinosis Q Lameness Locator (LL), and the IMU system Equisym (ES) across 2 different hard surfaces and to assess the interoperator reliability for the 2 IMU systems. Methods 8 mixed-breed research horses, aged 4 to 12 years, with varying degrees of gait asymmetries were utilized. To assess intrasystem reliability, horses were in-hand, straight-line trotted on either epoxy-coated concrete or rubber-coated concrete. Three trials were performed for LL and ES, while 6 concurrent trials were performed for AI-SPA. Interoperator reliability was assessed with 4 operators on the rubber-coated concrete only. Intraclass correlation coefficients and SE of measurements were calculated for 4 outcome parameters common to all systems as well as a variety of system-specific outcome parameters for LL and ES. Results Nearly all intraclass correlation coefficients indicated moderate to excellent intrasystem reliability (> 0.50) across the 3 systems (AI-SPA, 0.40 to 0.85; LL, 0.73 to 0.94; ES, 0.44 to 0.99) and were comparable between surfaces. Interoperator reliability was moderate to excellent for both LL (0.72 to 0.92) and ES (0.73 to 0.96). Standard error of measurement values remained relatively stable across study conditions. Conclusions Despite inherent horse variability and minor differences in testing conditions, objective gait evaluation systems consistently produced measurements indicating moderate to excellent reliability and low measurement error. Clinical Relevance These findings indicate that observed changes in system output are unlikely to be impacted by operator or hard-surface effects, supporting clinical reliability of these systems in routine practice when utilizing manufacturers’ instructions.