Kinematics of the hind limb in trotting horses after induced lameness of the distal intertarsal and tarsometatarsal joints and intra-articular administration of anesthetic.

This research investigates the changes in rear leg and pelvis movement observed in trotting horses following induced lameness in specific joints, and then following the administration of an anesthetic to those joints. The results seem to suggest that certain movement differences noted after the administration of the anesthetic can be reliable indicators of improvement in lameness of the affected joints.

Study Methodology

• The research included eight clinically healthy adult horses.
• The researchers used transient endotoxin-induced lameness in the distal intertarsal and tarsometatarsal joints as part of their study.
• Kinematic measurements, which relate to the movement of the limbs, were made at various stages: before inducing lameness, following lameness induction, and after intra-articular anesthetic administration to the affected joints.
• A total of fourteen displacement and joint angle measurements were made on various parts of the animals’ bodies including the right hind limb, sacrum, and the right and left tubera coxae.
• Statistical analysis was performed to compare the kinematic measurements under different conditions used in the study, including repeated measures ANOVA and a post hoc analysis using the Fisher’s least squared difference test.

Results of the Study

• Following the induction of lameness, significant changes observed in the horses’ kinematic variables included decreased fetlock and tarsal joint extension during stance, increased fetlock joint flexion and hoof height during swing, decreased limb protraction, and increased asymmetry in the vertical excursion of the tubera coxae.
• The intra-articular administration of the anesthetic resulted in some of these changes reverting towards their pre-lameness state, notably the limb protraction and the symmetry of the vertical excursion of the tubera coxae.

Conclusions

• The research concluded that examining the length of hind limb protraction and the symmetry in the vertical movement of the tubera coxae could serve as valuable indicators in identifying improvements in the joint lameness caused.
• Finally, the researchers highlighted the importance of viewing the horse from both the side, to assess limb protraction, and from the rear to assess the pelvic symmetry when evaluating changes in joint lameness.