Compensatory movements of horses with a stance phase lameness.

The study investigates the compensatory mechanisms in horses with lameness in one limb. It hypothesizes that horses with one lame limb exhibit a false limp in another leg, either on the side of the lame limb (ipsilateral forelimb) for the hindlimb lameness or on the opposite side (contralateral hindlimb) for the forelimb lameness. These findings suggest that the location of the actual lame limb can be deduced from the patterns of lameness.

Research Methodology

• The researchers showed two hypotheses for investigation: That horses with hindlimb lameness would show false lameness in the ipsilateral forelimb and those with forelimb lameness would show false lameness in the contralateral hindlimb.
• Fourteen horses with either fore- or hindlimb lameness were used as test subjects in this study. Their movements were observed and measured at a trot on a treadmill at a standardized speed.
• For some horses, diagnostic blocks were used before and after measurements (9 horses), and for others, the investigators introduced lameness (5 horses).

Data Collection Tools and Analysis

• Quantification tools, such as head acceleration asymmetry (HAAS) and sacrum acceleration asymmetry (SAAS), were used to measure fore- and hindlimb lameness respectively.
• Any changes in the lameness experienced by the horses were documented through alterations in either HAAS or SAAS parameters.
• Researchers analyzed data depending on which leg demonstrated lameness. In the four horses with ‘real’ hindlimb lameness, a false lameness appeared in the ipsilateral forelimb, supporting the first hypothesis.
• In contrast, six out of ten horses with forelimb lameness demonstrated lameness transfer indicative of the second hypothesis.

Study Results and Conclusions

• Overall, the findings indicated that horses with severe lameness in a forelimb showed signs of false lameness in the contralateral hindlimb, and horses with hindlimb lameness showed signs of false lameness in the ipsilateral forelimb.
• This suggests that the real location of lameness can be deduced from an analysis of the presence of lameness in two or more limbs of a horse, either on a sagittal or diagonal axis.
• This research hints at the adaptive and compensatory behavior in horses that extends our understanding of their physical limitations and the ways their bodies respond to injury or disability.