High-field magnetic resonance imaging investigation of distal border fragments of the navicular bone in horses with foot pain.
Authors: Biggi M, Dyson S
Journal: Equine veterinary journal
Summary
# Editorial Summary: Distal Border Fragments of the Navicular Bone Biggi and Dyson used high-field MRI to characterise distal border fragments of the navicular bone in 427 lame horses with foot pain, identifying 111 fragments and investigating their relationship to other osseous and soft tissue pathology. Rather than isolated lesions, distal border fragments showed significant associations with multiple other navicular abnormalities including osseous cyst-like lesions, increased synovial invaginations, entheseophyte enlargement, and increased bone signal intensity on fat-suppressed imaging. The researchers found a strong correlation between fragment presence and overall navicular bone pathology grade, suggesting these fragments exist within a spectrum of navicular disease rather than representing a discrete clinical entity. Although this study confirms that distal border fragments are part of broader navicular pathology rather than incidental findings, their specific contribution to lameness and pain remains incompletely understood. Equine professionals should interpret distal border fragments in the context of the complete MRI findings and clinical presentation rather than as isolated lesions, whilst recognising that clarifying their individual role in lameness requires further investigation.
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Practical Takeaways
- •Distal border fragments on MRI are part of navicular disease pathology and associate with other bone abnormalities, but their individual role in causing lameness cannot yet be determined from imaging alone
- •MRI grading of total navicular changes may be more diagnostically useful than fragment presence in isolation when evaluating chronic foot lameness
- •Further research is needed to establish whether managing distal border fragments specifically will improve clinical outcomes
Key Findings
- •111 of 427 lame horses (26%) had distal border fragments identified on high-field MRI
- •Significant association found between distal border fragments and increased total navicular bone grade, osseous cyst-like lesions, and enlarged synovial invaginations
- •Fragments correlated with increased signal intensity on fat-suppressed images and larger distal border entheseophytes
- •Despite associations with pathological changes, the direct contribution of fragments to pain and lameness remains unclear