Magnetic Resonance Imaging Findings of the Proximal Metacarpal Region in Warmblood Horses: 36 Lame and 26 Control Limbs (2015-2021).
Authors: van Veggel Elisabeth, Selberg Kurt, van der Velde-Hoogelander Brenda, Bolas Nick, Vanderperren Katrien, Bergman Hendrik Jan
Journal: Frontiers in veterinary science
Summary
# Editorial Summary This retrospective MRI study of 62 warmblood horses (36 lame limbs, 26 controls) examined bone and soft tissue pathology in the proximal metacarpal region, challenging some established assumptions about lameness prognosis in this anatomically vulnerable area. Whilst 81% of lame limbs demonstrated measurable abnormalities on imaging, the researchers found no correlation between lesion severity or type and return-to-work outcomes, with 58% of affected horses ultimately returning to similar or higher performance levels. Key findings included that proximal suspensory ligament (PSL) enlargement was notably *absent* in lame horses, yet specific lesion patterns—notably STIR signal hyperintensity within the dorsal PSL or proximal third metacarpal (McIII), and significant palmar cortical McIII resorption—warrant clinical attention as markers of genuine pathology. An important cautionary note emerged regarding contralateral (unaffected) limbs as control references; these frequently displayed intermediate-grade lesions and adaptive remodelling, suggesting they may not represent true normal anatomy. For practitioners, these findings suggest that a diagnosis of proximal metacarpal pathology need not be career-ending, whilst also highlighting that MRI sign severity alone should not dictate prognosis, and that careful interpretation of contralateral limb imaging is essential to avoid overdiagnosing clinically insignificant variations.
Read the full abstract on PubMed
Practical Takeaways
- •MRI hyperintensity in the dorsal PSL and proximal McIII are clinically relevant findings, but their presence alone should not be used to predict whether a horse will or won't return to work
- •Normal or contralateral limbs frequently show mild degenerative changes and adaptive remodeling—don't assume they represent true 'normal' when comparing to the lame side
- •PSL enlargement is NOT a feature of proximal metacarpal lameness in this population; focus instead on signal changes and bone resorption patterns on MRI
Key Findings
- •PSL size was not enlarged in lame horses compared to controls, but hyperintensity on T1W/T2*W GRE and STIR imaging was only present in lame limbs
- •81% of lame limbs showed bone and soft tissue abnormalities, but lesion severity did not correlate with return to work ability
- •58% of lame warmbloods returned to work at similar or higher levels regardless of MRI lesion characteristics
- •Palmar cortical McIII resorption and dorsal margin irregularity were more severe in lame limbs, but mild changes also appeared in control limbs and contralateral non-lame limbs