Background: Topline dysfunction in horses has been defined as a complex condition involving weakness,
hypomobility, and generalized back pain and is strongly associated with hindlimb lameness
in horses. Traditionally, spinal motion in horses has been described using displacement
measurements, predominantly in the sagittal plane; however, these do not fully describe
the complexity of movement which may be present in horses with topline dysfunction.
This exploratory study considered the use of joint angles to assess joint excursions
and joint angular velocity to assess the quality of movement in all three planes,
with the latter being previously shown to offer greater sensitivity when assessing
humans with and without chronic low back pain.
Materials and Methods: Six degrees of freedom spinal motion during trot of six thoroughbred and thoroughbred
cross horses (two geldings, four mares, four sound, and two with hindlimb lameness)
were recorded (Vicon, UK) using marker clusters centred over the cranial thoracic,
caudal thoracic, lumbar, and sacral segments, and the angles and angular velocities
were calculated between segments using Visual 3D (HAS Motion, Canada).
Results: Joint angles and angular velocity were both able to detect asymmetries with the sound
horses showing more symmetrical movement patterns in all three planes; however, angular
velocity showed notably greater values in the lame horses indicating decreased quality
of movement/control, [Fig. 1].
Fig. 1 (A) Sound horse caudal thoracic to lumbar movement during trot. (B) Lame horse caudal thoracic to lumbar movement during trot.
Conclusion: Angular velocity yielded new information on the quality of movement in the three
rotational planes and may provide more detail in the assessment of topline dysfunction
and the efficacy of its management in horses.
