Clinical significance of osseous spurs on the dorsoproximal aspect of the third metatarsal bone.
Authors: Fairburn A, Dyson S, Murray R
Journal: Equine veterinary journal
Summary
# Editorial Summary Dorsoproximal third metatarsal bone (MtIII) spurs are a frequent radiological finding, yet their diagnostic value has remained unclear until now. Fairburn, Dyson and Murray examined radiographs from 455 horses—including 355 with hindlimb lameness across various diagnoses and 100 clinically normal controls—to establish whether these bony projections correlated with lameness, specific diagnoses like proximal suspensory desmitis or distal tarsal joint pathology, and to clarify whether they represented true osteophytes or enthesis-related changes. Spurs were identified in 25% of all horses with no significant difference between lame and sound populations, nor between horses with proximal suspensory desmitis/distal tarsal pain and those with other hindlimb conditions; however, spur presence showed a statistically significant association with radiological abnormalities in the distal tarsal joints (tarsometatarsal joint P = 0.018, centrodistal joint P = 0.027). The authors conclude that isolated MtIII spurs are likely incidental findings, but their presence warrants careful evaluation of the distal hock joints as a possible indicator of early osteoarthritis—and crucially, intra-articular diagnostic analgesia remains essential to establish genuine clinical significance in individual cases rather than relying on radiographs alone. This finding has important implications for practitioners interpreting hindlimb radiographs, particularly when considering whether MtIII spurs warrant further investigation or intervention.
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Practical Takeaways
- •Do not assume a dorsoproximal MtIII spur is clinically significant in isolation—always correlate with other radiological findings and lameness diagnostics
- •Osseous spurs appear more frequently in hocks with distal tarsal joint osteoarthritis, so they may serve as a radiological indicator of this pathology
- •Intra-articular analgesia blocks of the distal tarsal joints should be used to confirm whether a spur is the source of lameness before committing to treatment
Key Findings
- •Osseous spurs were present in 25% of horses examined, with 13% of horses with bilateral radiographs showing bilateral spurs
- •No significant difference in spur frequency between lame and clinically normal horses, or between different hindlimb lameness diagnoses
- •Osseous spurs were significantly associated with radiological abnormalities in distal tarsal joints (tarsometatarsal P=0.018; centrodistal P=0.027)
- •Spurs without other radiological abnormalities may be incidental findings; clinical significance requires intra-articular analgesia confirmation