Spondylosis in Horses: Clinical Features, Diagnostic Imaging Findings, Treatment and Outcome in 13 Horses.

Background: Back pain is a debilitating condition hampering horses' athletic careers. Thoracic spondylosis (TS), a known cause of back pain, leads to osteophytes formation across intervertebral joints. In horses, TS is poorly reported, with anecdotal signs and response to treatment.

Objectives: To report clinical presentation, diagnostic imaging findings, treatment and outcome in horses with TS.

Methods: The clinical records of horses diagnosed with TS between 2010 and 2023 were reviewed. Signalment, clinical and imaging findings, treatment, and outcome were analysed. Thoracic spondylosis was graded from 1 to 5. Grades, concurrent pathologies, treatment, and outcome were assessed. The median TS grade and number of lesions and outcome were compared using the Mann-Whitney test.

Results: Thirteen horses met inclusion criteria, eight of which performed a discipline involving jumping. All horses exhibited signs consistent with back pain. Thoracic spondylosis sites varied from 1 to 6 (mean 2) with a total of 32 lesions. The most affected site was T13-T14. Five horses had concurrent dorsal spinous processes impingement and three were lame. Treatment included physiotherapy, tiludronate, anti-inflammatory and extracorporeal shockwave therapy. Long-term follow-up (>12 months) was available for 11 horses: the outcome was poor in seven horses, good in one and excellent in three. No statistically significant association was found between TS grade (p = 0.4), number of lesions (p = 0.2) and outcome categories.

Conclusions: Although rare, TS can cause back pain. The outcome is generally poor, but some horses may continue athletic activity despite severe lesions.