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

To determine if the pain of the third phalanx due to sidebone fracture in horses canbe 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 tosidebone fracture.Procedures- Seven mix breed show jumping horses were selected from horses with unilateralforelimb lameness. Selection of the horses was based on the results of radiographicexamination for fracture of the sidebone, response to the palmar digital nerve block andanalgesia of the navicular bursa. Horses examined at walk and trot. Flexion tests and hooftester examination of the lame forelimb were positive. Dorsopalmar radiograph examinationrevealed sidebone fracture. No abnormality was seen in other parts of the limb in lateral viewradiographs. The horses did not shown any improvement 10 minutes after analgesia of thenavicular bursa but the lameness improved profoundly after palmar digital nerve block. Thelameness score was graded by the scale described by American Association of EquinePractitioners.Results- The lameness score was significantly reduced 5 minutes after palmar digital nervesblock in walk and trot (P 0.05). No significant difference was seen in walk and trot 5 minutesafter distal interphalangeal joint analgesia ( P 0.05), but significant difference was seen inlameness 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 phalanxproblem like sidebone fracture, should not be eliminated as a possible cause of lameness,when lameness is significantly reduced by diagnostic analgesia of distal interphalangeal jointor palmar digital nerves block.