Severe carpometacarpal osteoarthritis in older Arabian horses.
Authors: Malone Erin D, Les Cliff M, Turner Tracy A
Journal: Veterinary surgery : VS
Summary
This retrospective analysis of 405 carpal radiograph sets identified a severe, degenerative form of carpometacarpal osteoarthritis disproportionately affecting Arabian horses, with 74% of the 31 affected cases occurring in this breed and an average age of presentation of 14.4 years. The researchers examined necropsy specimens alongside radiographic evidence of marked osteoproliferative reactions at the CMC joint and discovered a striking anatomical variation: the palmar articulation between the second and third metacarpal bones was absent in 48% of Arabian horses at one centre but present in all eight Arabians examined at another centre, whilst non-Arabian horses showed much lower prevalence rates (12.5% and 24% respectively). By presentation, most affected horses were no longer rideable, and ten required euthanasia due to severe lameness; notably, only 34.8% of the Arabian cases had documented trauma histories, suggesting either that subtle injuries precipitate disproportionate degeneration or that predisposing anatomical factors play a significant role. The findings suggest that geographical variation in the prevalence of absent palmar CMC articulations may underlie the breed and regional susceptibility to this crippling condition, whilst prior trauma—even apparently minor—may trigger unexpectedly aggressive osteoarthritis in genetically predisposed individuals. For practitioners managing Arabian horses with carpal disease, this research highlights the importance of recognising CMC-OA as a potentially career-ending diagnosis and considering anatomical predisposition when counselling owners about prognosis following carpal injury.
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Practical Takeaways
- •Arabian horses, particularly older individuals, are at substantially higher risk for severe carpometacarpal osteoarthritis; increased monitoring is warranted for this breed
- •Even mild carpal trauma in Arabian horses may progress to crippling osteoarthritis due to potential anatomical variations; aggressive early intervention and conservative management post-trauma are critical
- •The absence of a palmar articulation between metacarpal bones in some Arabian horses may predispose them to abnormal load distribution and accelerated joint degeneration
Key Findings
- •74% of 31 horses with marked CMC osteoproliferative reaction were Arabian horses, with average age of 14.4 years
- •34.8% of affected Arabian horses had known carpal trauma history
- •Palmar articulation between 2nd and 3rd metacarpal bones was absent in 48% of Arabian horses at one center versus 12.5% of non-Arabian horses
- •10 of 31 horses (32%) were euthanatized due to lameness severity, with most horses non-rideable at presentation