“One of these modalities is chiropractic care, which has been increasing in prevalence in a veterinary setting, is affordable to the majority of our veterinary clients, and has been used for the treatment of back pain in horses,” said Samantha Parkinson, DVM, a veterinary resident in equine field service in Colorado State University’s (CSU) Department of Clinical Sciences, in Fort Collins.

At the 2021 American Association of Equine Practitioners (AAEP) Convention, held Dec. 4-8 in Nashville, Tennessee, Parkinson shared results from a recent study she co-authored assessing chiropractic’s effects on limb lameness with concurrent axial skeleton pain in horses.

The Connection Between Lameness and Back Pain

Lameness impacts far more than just a horse’s affected limb. Research has shown it can cause secondary pain in the axial (vertebrae, skull, ribs, and sternum) and appendicular (limbs and pelvis) skeleton as the horse compensates for the pain.

“When one leg is lame, there’s altered weight-bearing to increase the weight in the other three limbs as the horse attempts to unload the painful leg,” Parkinson explained. “As the horse unweights the leg, there’s spinal compensation that occurs throughout the axial skeleton, including muscle guarding, weight-shifting, and stiffness.”

She said study results have shown 23-32% of horses with limb lameness had concurrent back pain, and 68-85% of horses with back pain had concurrent limb lameness.

“This highlights the importance and the significance of these interactions and our need to be able to address them,” she said, adding that one modality veterinarians use to address them is chiropractic. This manual therapy has been shown to reduce pain and improve axial skeleton kinematics, pelvis symmetry, and muscle tone.

Assessing Chiropractic Therapy’s Effects

In their study, Parkinson and her team aimed to determine whether chiropractic treatment could improve both lameness and back pain. They recruited 20 horses from CSU’s polo team with Grades 1-3 (on the five-point AAEP scale) lameness. Ten were in the treatment group, and 10 served as controls. A blinded clinician performed objective and subjective lameness exams as well as spinal exams on all horses on Days 0, 14, and 28. The horses received chiropractic treatments on Days 0, 7, 14, and 21.

While the team observed no changes in lameness scores, Parkinson said they did note significant changes in compensatory mechanisms, including decreased muscle hypertonicity (tension) and stiffness across several sites on the axial skeleton. Spinal pain scores also decreased significantly over the five-week study period.

“Therefore, we concluded that chiropractic care may be beneficial for addressing compensatory pain and dysfunction that result from a primary lameness,” she said.