Sagittal plane fore hoof unevenness is associated with fore and hindlimb asymmetrical force vectors in the sagittal and frontal planes.
Authors: Hobbs Sarah Jane, Nauwelaerts Sandra, Sinclair Jonathan, Clayton Hilary M, Back Willem
Journal: PloS one
Summary
# Editorial Summary Forefoot unevenness—a difference of more than 1.5 degrees in dorsal hoof wall angle between left and right forelimbs—creates asymmetrical loading patterns that extend well beyond the uneven feet themselves. Hobbs and colleagues used three-dimensional force plate analysis during trotting in 34 horses to quantify how compensatory mechanics develop across all four limbs when hoof angles are imbalanced, examining both sagittal (fore-aft) and frontal (side-to-side) ground reaction force vectors. The higher-angled forelimb consistently generated more propulsive forces, whilst the lower-angled limb produced greater braking forces; importantly, horses with right forelimb unevenness displayed medial loading in the high hoof and lateral loading in the low hoof, indicating frontal plane instability. Hindlimb compensations were asymmetrical and complex—the right hind showed load-related changes whilst the left hind exhibited significantly greater lateral forces regardless of which forefoot was higher, suggesting the musculoskeletal system is attempting to stabilise movement in a plane for which it is biomechanically poorly adapted. These findings reinforce that even minor hoof imbalances (>1.5 degrees) warrant corrective farriery, as the resulting frontal plane loading increases injury risk and places substantial compensatory demands on hindquarters—particularly relevant for practitioners managing performance horses or those with emerging lameness of unclear origin.
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Practical Takeaways
- •Routine assessment of dorsal hoof wall angle symmetry is warranted—aim for <1.5° difference between fore hooves, as asymmetry creates abnormal sideways loading forces that normal equine anatomy cannot handle efficiently.
- •Hoof unevenness causes cascade compensation patterns down the chain: contralateral forelimb, then primarily the opposite hindlimb; correcting the foot problem early may prevent secondary soft tissue injuries in limbs distant from the initial imbalance.
- •Horses with uneven hooves face elevated locomotory demands and asymmetrical stress; farriery corrections should prioritize symmetry, and concurrent physiotherapy or training modification may be needed during rebalancing.
Key Findings
- •Fore hoof unevenness >1.5° in dorsal hoof wall angle was present in 79% of riding horses (n=27/34) and significantly altered ground reaction force vectors in both sagittal and frontal planes.
- •Uneven forelimbs showed increased propulsive forces in the higher hoof and medial/lateral force asymmetries between limbs, with the high right forefoot producing medial forces while the low left forefoot produced lateral forces.
- •Hindlimb compensatory patterns occurred only in the right hind limb with significantly greater lateral ground reaction forces in the left hind across both high-left and high-right forefoot groups.
- •Uneven hooves create abnormal frontal plane loading that the equine musculoskeletal system is poorly adapted to tolerate, suggesting elevated injury risk compared to even-hoofed horses.