The centrodistal joint interosseous ligament region in the tarsus of the horse: Normal appearance, abnormalities and possible association with other tarsal lesions, including osteoarthritis.
Authors: Skelly-Smith E, Ireland J, Dyson S
Journal: Equine veterinary journal
Summary
# Editorial Summary: Centrodistal Joint Interosseous Ligament Abnormalities in the Horse Tarsus Skelly-Smith, Ireland and Dyson's retrospective analysis of 700 horses established the normal radiographic appearance of the centrodistal joint interosseous ligament region—typically an oval or circular radiolucent space with uniform bone margins—and identified abnormalities in 17.3% of lame or affected limbs. Logically, heavier horses showed reduced odds of developing these abnormalities, whilst 36.4% of horses with interosseous ligament region changes displayed concurrent osteoarthritis of the centrodistal joint, compared to only 0.5% of those with normal anatomy (P<0.001). A particularly clinically relevant finding emerged: radiological evidence of interosseous ligament abnormalities and associated osteoarthritic changes may exist without producing lameness or distal tarsal pain, challenging the assumption that radiographic findings always correlate with clinical signs. These results emphasise the importance of thorough tarsal radiographic interpretation and highlight that asymptomatic mineralisation or ossification of the interosseous ligament warrants monitoring, as it may represent early degenerative change with future clinical implications for performance horses.
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Practical Takeaways
- •Radiological abnormalities of the centrodistal interosseous ligament region are common findings (17.3%) but do not always correlate with clinical lameness, so radiographs must be interpreted alongside clinical examination
- •When interosseous ligament abnormalities are found, there is a substantially elevated risk (36.4%) of concurrent centrodistal joint osteoarthritis, warranting careful assessment of the entire tarsal joint
- •Lighter horses appear more predisposed to interosseous ligament abnormalities, suggesting body weight management may be relevant to tarsal health
Key Findings
- •Interosseous ligament region abnormalities were present in 17.3% of 700 horses examined radiographically, predominantly affecting the lame(r) limb
- •36.4% of horses with interosseous ligament region abnormalities had concurrent radiological osteoarthritis of the centrodistal joint, compared to only 0.5% without such abnormalities (P<0.001)
- •Increasing bodyweight was associated with significantly decreased odds of interosseous ligament region abnormalities
- •Radiological abnormalities of the interosseous ligament region and osteoarthritis may be present without clinical signs of distal tarsal joint pain