Osteoarthritis of the thoracolumbar synovial intervertebral articulations: clinical and radiographic features in 77 horses with poor performance and back pain.
Authors: Girodroux M, Dyson S, Murray R
Journal: Equine veterinary journal
Summary
# Editorial Summary: Thoracolumbar Facet Joint Osteoarthritis and Equine Back Pain Back pain remains a significant cause of poor performance in horses, yet the contribution of facet joint (synovial intervertebral articulation) pathology to clinical signs has historically been underinvestigated. This retrospective analysis examined 77 horses with radiographic evidence of thoracolumbar facet joint osteoarthritis and clinical back pain, finding that lesions most commonly affected 2–5 joints in the caudal thoracic and cranial lumbar region (T15–L1), with sclerosis, periarticular osteophytes and joint space narrowing being the predominant radiographic features. Interestingly, neither the number of affected joints nor lesion severity grade correlated with clinical sign intensity; instead, the presence of concurrent osseous abnormalities—particularly impinging dorsal spinous processes—significantly altered the clinical presentation. Breed, gender, age and bodyweight showed no predisposition to facet joint disease, though showjumpers were statistically less affected than horses in other disciplines. These findings suggest that whilst thoracolumbar facet joint osteoarthritis contributes to back pain presentation, its clinical significance appears modulated by additional spinal pathology rather than being directly proportional to lesion extent, highlighting the importance of comprehensive spinal imaging when investigating performance problems and the need for further prevalence studies in asymptomatic populations to establish causation.
Read the full abstract on PubMed
Practical Takeaways
- •Facet joint osteoarthritis should be considered as a primary diagnosis in horses presenting with thoracolumbar pain and poor performance, not just as an incidental finding
- •Multiple lesions in the caudal thoracic/cranial lumbar region are common; imaging should focus on T15-L1 when back pain is suspected
- •The presence of dorsal spinous process impingement significantly alters clinical presentation, so concurrent abnormalities should be assessed to guide prognosis and treatment decisions
Key Findings
- •Facet joint osteoarthritis occurred in 2-5 joints per horse, predominantly in caudal thoracic and cranial lumbar spine (T15-L1)
- •Sclerosis, periarticular new bone, and joint space narrowing were the most common radiographic lesion types
- •Showjumpers were significantly less affected than horses in other disciplines
- •Clinical sign severity correlated with presence of other osseous abnormalities rather than number of affected joints or lesion grade