Effects of analgesia of the distal interphalangeal joint or palmar digital nerves on lameness caused by solar pain in horses.
Authors: Schumacher J, Steiger R, Schumacher J, de Graves F, Schramme M, Smith R, Coker M
Journal: Veterinary surgery : VS
Summary
# Editorial Summary Sole pain remains a clinically significant cause of lameness in horses, yet determining its precise origin and appropriate treatment requires careful diagnostic approach. Using an experimental model of dorsal solar margin pressure in six horses, researchers compared the analgesic effects of intra-articular DIP joint injection versus palmar digital nerve blocks, finding that lameness scores decreased significantly following both interventions whilst saline injection into the joint produced no improvement. These findings demonstrate that both regional techniques effectively desensitise nociceptive pathways from the solar region, though through anatomically distinct mechanisms—the DIP joint injection likely blocking intra-articular pain receptors whilst the PD nerve block interrupts peripheral sensory input from the sole itself. For practitioners, the practical implication is clear: a positive response to either diagnostic analgesia technique should prompt thorough solar examination rather than defaulting to DIP joint pathology as the explanation, as sole pain can mimic and coexist with joint-related lameness. This distinction carries significant weight in treatment planning, since appropriate farriery intervention (pressure relief, therapeutic shoeing) may resolve the underlying problem where intra-articular analgesia alone would prove merely palliative.
Read the full abstract on PubMed
Practical Takeaways
- •When DIP joint or palmar digital nerve blocks resolve lameness, always consider sole pain as a differential diagnosis—don't automatically attribute improvement to joint or nerve pathology alone
- •Use diagnostic anesthesia strategically: sole pain may be masked by joint or nerve blocks, potentially misleading your diagnostic approach
- •Farriers and vets should collaborate on pressure-related sole pain cases, as therapeutic shoeing modifications (reducing sole pressure) may be as effective as medication
Key Findings
- •Lameness induced by sole pressure remained high after saline injection into DIP joint but decreased significantly (P ≤ 0.05) after local anesthetic into DIP joint
- •Local anesthetic around palmar digital nerves significantly reduced lameness scores caused by solar pain
- •Analgesia of either DIP joint or palmar digital nerves desensitizes at least a portion of the sole, indicating these structures are sensory pathways for sole pain