Multi-planar intersegmental angular velocity in the assessment of topline movement in horses

Objective A recent survey of a large group of equine clinicians found a need for more objective assessment techniques for quality of movement, especially related to horses with clinical topline dysfunction. This study measured intersegmental movement in the sagittal, dorsal and transverse planes of the cranial thoracic to caudal thoracic (CRT-CDT), caudal thoracic to lumbar (CDT-LUM), and lumbar to sacral (LUM-SAC) segments using range of motion and angular velocity as measures of quality of movement Methods Six degrees of freedom spinal motion was measured at the walk and trot in 3 sound Thoroughbred and Thoroughbred cross horses, and the data were pooled giving a total of 54 gait cycles at walk and 33 at trot. These were compared against 8 cycles at walk and 13 at trot from one Thoroughbred horse that was confirmed as having moderate/severe impact and push off lameness in the right hindlimb. Results Both joint angles and angular velocities detected differences between the sound horses and the lame horse with angular velocity showing notably greater differences in absolute values and percentages compared with joint angles. Conclusions The between-group differences indicated decreased quality of movement/control in the lame horse and this was most apparent when trotting. Clinical Relevance Intersegmental angular velocity is measured non-invasively and may be used to assess quality of intersegmental movement in horses as it does in humans. Further investigation to assess angular velocity throughout treatment of topline dysfunction of the horse and its association with different lameness patterns is warranted.