The effect of induced hindlimb lameness on thoracolumbar kinematics during treadmill locomotion.
Authors: Gomez Alvarez C B, Bobbert M F, Lamers L, Johnston C, Back W, van Weeren P R
Journal: Equine veterinary journal
Summary
# Editorial Summary: Hindlimb Lameness and Thoracolumbar Kinematics The relationship between hindlimb lameness and spinal motion remains poorly characterised, despite the clinical observation that horses with subtle hindlimb dysfunction often present with secondary back problems. Gomez Alvarez and colleagues used reflective marker tracking during treadmill locomotion to measure thoracolumbar kinematics in six horses before and after inducing mild (grade 2) lameness via sole pressure—a model that mimicked naturally occurring subtle lameness without necessarily producing measurable unloading of the affected limb in all animals. The results revealed statistically significant compensatory changes in spinal motion: at walk, the thoracic segments showed increased flexion-extension range of motion and the pelvis demonstrated increased axial rotation, whilst the mid-lumbar region (L3-L5-S3) showed reduced flexion-extension range during trot. Notably, during the stance phase of the lame hindlimb, the thoracolumbar spine adopted a more extended posture with the neck lowered, yet stride length and limb protraction angles remained unchanged. These findings underscore the biomechanical interdependence of hindlimb function and spinal stability; practitioners should recognise that even clinically subtle hindlimb lameness can trigger measurable spinal compensation patterns that, if left unaddressed chronically, may precipitate secondary back dysfunction and warrant intervention beyond the limb itself.
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Practical Takeaways
- •Subtle lameness that may not be obvious through traditional gait assessment can still trigger compensatory changes throughout the thoracolumbar spine—monitor back kinematics, not just limb movement, when evaluating lame horses
- •Chronic subtle lameness may predispose horses to back dysfunction through sustained hyperextension and altered rotational patterns; address even mild hindlimb issues early to prevent secondary spinal problems
- •Inconsistent limb loading does not always accompany detectable lameness; kinematic analysis of the back can reveal lameness-induced compensation when traditional force plate data appears normal
Key Findings
- •Subtle hindlimb lameness increased flexion-extension range of motion at walk, particularly in thoracic segments, despite inconsistent limb unloading across subjects
- •Lumbosacral segment (L3-L5-S3) showed decreased flexion-extension ROM at trot during induced lameness
- •During stance phase of the lame limb, thoracolumbar segments became hyperextended and pelvis axial rotation increased at both gaits
- •Stride length and protraction-retraction angles showed no significant changes despite kinematic alterations in the back