Kinematic adaptions to induced short-term pelvic limb lameness in trotting dogs

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 The affected limb was retracted more, while the contralateral limb was protracted more, consistent with this limb bearing more body weight in lame dogs.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.

Keywords: Angular excursion; Compensatory mechanism; Hindlimb lameness; Kinematics.

Fig. 1

Limb angles during sound and lame trotting. Comparison of thoracic and pelvic limb angles at touch-down (dark grey), lift-off (light grey) and mid-stance (black, dashed line) relative to the vertical during sound and lame trotting. Numbers below each stick-figure represent the means for all dogs (see Fig. 1 in 16 for further explanation and Appendix: Supplementary Tables S1 and S2 for details). Note the greater retraction of the affected (i.e. ipsilateral) and the greater protraction of the contralateral pelvic limbs

Fig. 2

Angular excursions during sound and lame trotting. Stride-phase normalized angular excursion of the thoracic (top) und pelvic (bottom) limbs. The traces represent the mean and standard deviation (error bars) of all dogs during sound (black) and lame (grey) trotting. Bars above each graph indicate significant differences based on the bin-by-bin analysis with the respective colour indicating the significantly greater value. Labels on the right indicate increasing pro- or retraction of the limb (i.e. Protr. and Retr., respectively)

Fig. 3

Thoracic and pelvic limb positions during sound and lame trotting. Stick-figures of the thoracic and pelvic limbs illustrating limb positions at touch-down and lift-off during sound (black) and lame trotting (grey) when averaged for all dogs

Fig. 4

Thoracic limb segment and joint angular excursions. Stride-phase normalized angular excursions of the segment and joint angles of the thoracic limbs (further details as in Fig. 3). Labels on the right indicate increasing ante-or retroversion for the segments (i.e. Antev. and Retrov., respectively) and flexion and extension for the joints

Fig. 5

Pelvic limb segment and joint angular excursions. Stride-phase normalized angular excursions of the segment and joint angles of the pelvic limbs (further details as in Fig. 4)