Evaluation of Palmar Digital Nerve Block and Distal Interphalangeal Joint Analgesia in Lame Horses Associated with Hoof Pain due to Sidebone Fracture

Objective- To determine if the pain of the third phalanx due to sidebone fracture in horses can be attenuated by analgesia of the distal interphlangeal joint and palmar digital nerve block. Design- Clinical study. Animals- Seven horses with unilateral forelimb lameness associated with hoof pain due to sidebone fracture. Procedures- Seven mix breed show jumping horses were selected from horses with unilateral forelimb lameness. Selection of the horses was based on the results of radiographic examination for fracture of the sidebone, response  to the palmar digital nerve block and analgesia of the navicular bursa. Horses examined at walk and trot. Flexion tests and hoof tester examination of the lame forelimb were positive. Dorsopalmar radiograph examination revealed sidebone fracture. No abnormality was seen in other parts of the limb in lateral view radiographs. The horses did not shown any improvement 10 minutes after analgesia of the navicular bursa but the lameness  improved profoundly after palmar digital nerve block. The lameness score was graded by the scale described by American Association of Equine Practitioners.     Results- The lameness score was significantly reduced 5 minutes after palmar digital nerves block  in walk and trot (P<0.05). No significant difference was seen in walk and trot 5 minutes after distal interphalangeal joint analgesia ( P>0.05), but significant difference was seen in lameness grading 15 minutes after distal interphalangeal joint analgesia both in walk and trot (P<0.05). Conclusion and Clinical Relevance- It is concluded that pain arising from the third phalanx problem like sidebone fracture, should not be eliminated as a possible cause of lameness, when lameness is significantly reduced by diagnostic analgesia of distal interphalangeal joint or palmar digital nerves block.