How dogs change their trot when one back leg is lame

Abstract

BACKGROUND: Lameness due to paw injuries is common in the clinical practice. Although many studies investigated gait adaptations to diseases or injuries, mainly of the hip and knee, our understanding of the biomechanical coping mechanisms that lame dogs utilize is limited. Therefore, this study evaluated the kinematic changes associated with an induced, load-bearing pelvic limb lameness in healthy dogs trotting on a treadmill. Kinematic analysis included spatio-temporal comparisons of limb, joint and segment angles of all limbs. Key parameters compared between sound and lame conditions were: angles at touch-down and lift-off, minimum and maximum joint angles and range of motion. RESULTS: Significant differences were identified in each limb during both stance and swing phases. The most pronounced differences concerned the affected pelvic limb, followed by the contralateral pelvic limb, the contralateral thoracic limb and, to the least degree, the ipsilateral thoracic limb. The affected limb was retracted more, while the contralateral limb was protracted more, consistent with this limb bearing more body weight in lame dogs. CONCLUSIONS: Kinematic adaptations involved almost all segment and joint angles in the pelvic limbs, while they exclusively concerned distal parts of the thoracic limbs. Comparisons with tripedal locomotion reveal several striking similarities, implying that dogs use similar principles to cope with a partial or a total loss in limb function. Because kinematic alterations occurred in all limbs and not just the affected one, all limbs should be included in routine follow-ups and be part of the diagnostic and therapeutic care of canine patients.