Effect of induced hindlimb length difference on body-mounted inertial sensor measures used to evaluate hindlimb lameness in horses.
Authors: Pitts Jael B, Kramer Joanne, Reed Shannon K, Schiltz Paul, Thombs Lori, Keegan Kevin G
Journal: PloS one
Summary
# Editorial Summary Induced hindlimb length differences—created by applying a glued boot shoe to one hind limb—produce measurable asymmetries in pelvic motion that body-mounted inertial sensors can reliably detect across varied surfaces and movement patterns in horses. Sixteen horses were evaluated using inertial measurement units whilst trotting straight and lunging on both hard and soft footing, with pelvic height changes (minimum and maximum) calculated to identify impact-phase and pushoff-phase lameness patterns. The elevated limb generated consistent impact-phase asymmetries (Pmin changes) in all conditions, whilst the opposite limb showed significant pushoff-phase asymmetries (Pmax changes) only during straight-line trotting, not lunging. This suggests that inertial sensor technology effectively captures subtle compensatory movement patterns that might otherwise escape clinical observation, though the biomechanical response differs depending on task demands and surface compliance. For practitioners using or interpreting sensor-based lameness assessments, these findings highlight that movement context and footing type influence which asymmetries become apparent, emphasising the importance of standardising both test conditions and the specific parameters being evaluated when comparing serial measurements or trending a horse's response to treatment.
Read the full abstract on PubMed
Practical Takeaways
- •Inertial sensor measurements (Pmin/Pmax) can reliably detect hindlimb lameness caused by limb length differences, making this technology useful for objective lameness assessment in practice.
- •Gait pattern (straight vs. circular) affects which lameness parameters are detectable—pushoff-phase asymmetries may be masked during lunging, so evaluate lame horses on both straight lines and circles.
- •Even 10mm height differences create measurable lameness signatures; use this knowledge when assessing horses with subtle gait abnormalities or suspected uneven shoe wear.
Key Findings
- •Induced hindlimb elevation caused significant changes in minimum pelvic height (Pmin) on both hard and soft surfaces during straight-line trotting and lunging, indicating impact-type lameness in the elevated limb.
- •Maximum pelvic height (Pmax) changes indicating pushoff-type lameness in the non-elevated contralateral limb were significant during straight-line trotting but not during lunging.
- •Body-mounted inertial sensors detected lameness asymmetries created by 10mm hindlimb length differences across multiple movement patterns and surfaces.