Limb movement adaptations in horses with experimentally induced fore- or hindlimb lameness

The kinematic patterns of all limbs of 11 clinically nonlame Dutch Warmblood horses were studied during induced supporting limb lameness to gain insight into the compensation mechanisms horses use to manage lameness and to test kinematic limb variables for their significance as lameness indicators. Using the locomotion analysis system CODA-3, the kinematics of the horses were recorded while walking (1.6 m/s) and trotting (3.5 m/s) on a treadmill. A transient lameness model, evoking pressure on the hoof sole, was used to induce 3 degrees of fore- and hindlimb lameness. Joint angle patterns and hoof movements were analysed using joint angle/time diagrams and the hoof trajectories in the sagittal plane. Quantitative analysis of 13 selected variables in each limb was done using a 2-way analysis of variance. Hyperextension of the fetlock joint and flexion of the coffin joint during the stance phase decreased significantly (P < 0.05) in the lame limb, both in fore- and hindlimb lameness, at both gaits. In the contralateral nonlame limbs both variables increased compensatorily. Flexion increased with increasing lameness in the proximal joints, i.e. the shoulder joint and even more the tarsal joint of the lame limb. The retraction of both forelimbs decreased during forelimb lameness at the walk, while in the lame hindlimb the protraction decreased. The hoof arcs were lower in the lame limb than in the nonlame limb, due to an increased hoof height in the nonlame limb during forelimb lameness and to a decreased height in the lame limb during hindlimb lameness. It was concluded that patterns of the distal joints reflect the different loadings of the limbs during lameness. Proximal joints acted as load dampers to reduce peak forces in the lame limb. Hyperextension of the fetlock and flexion of the coffin joint proved to be the most sensitive indicators for fore- and hindlimb lameness.