Evaluation of clinical examination for differential diagnosis of lameness by navicular apparatus or heel pain in horses

To evaluation of clinical examination for differential diagnosis of navicular region pain from other forms of palmar heel pain in the forelimb of horses the present study was undertaken.Thirty four horses with lameness referable to the palmar aspect of the hoof based on their response to the palmar digital nerves analgesia were divided into 2 groups based on their response to both distal interphalangeal joint and navicular bursa analgesic injection. Horses that were profoundly improved by both analgesic blocks were considered to have navicular region pain whereas, all other horses were considered to have other cause of palmar heel pain. The responses to various diagnostic tests such as hoof tester, distal limb flexion and frog and toe wedge tests were compared between the groups.For all diagnostic tests, sensitivity, specifity, accuracy and positive predictive values for navicular pain were calculated. Nineteen of 34 horses had navicular region pain. There was no difference in the responses between groups.The single most accurate diagnostic test was analgesia of the distal interphalangeal joint for navicular region pain.