Although assessment of multilimb lameness is frequently performed in clinical practice, it can be challenging, and it is essential to consider the effect of compensatory lameness to correctly identify the primary lame limb. Recently, our group investigated the effect of forelimb lameness on pelvic movement asymmetry in a clinical population of equine patients.1 However, hind limb compensatory lameness has not been extensively characterized in a substantial number of clinical patients, although it is commonly referred to and described by the so-called law of sides, which states that, in a horse with apparent forelimb and contralateral hind limb lameness, lameness of the hind limb is frequently compensatory in nature, whereas in a horse with apparent hind limb and ipsilateral forelimb lameness, lameness of the forelimb is frequently compensatory. The compensatory component is not a true lameness.2–5 In horses with true forelimb lameness, the height of the head is different between stride phases of the right and left forelimbs. The HDmax after the stance phases of the right and left forelimbs changes (increases) with forelimb lameness owing to weaker push-off from the affected forelimb. During the stance phase, there is less downward movement of the head when the horse bears weight on the lame limb, as reflected in the minimum head height. This difference in head position during various phases of the stride of the left and right forelimbs is indicative of forelimb lameness.1
The objective of the study reported here was to characterize the compensatory load redistribution that results from hind limb lameness and to describe its effect on head movement in horses. We hypothesized that hind limb lameness would result in substantial load redistribution, which would be observed as ipsilateral forelimb lameness.
Supported by the University of Glasgow.
The authors declare that there were no conflicts of interest.
Presented in part at the 60th Annual Convention of the American Association of Equine Practitioners, Salt Lake City, December 2014.
The authors thank Dr. Lance Voute for assistance in instrumenting horses with the inertial sensor-based system and performing lameness investigations at the University of Glasgow.
Maximum head height difference
Minimum head height difference
Maximum pelvic height difference
Minimum pelvic height difference
Lameness Locator, Equinosis LLC, St Louis, Mo.
SigmaPlot 11.2, Systat Software LLC, San Jose, Calif.
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