A study of 118 cases of navicular disease: clinical features

The clinical features are reported from 118 horses (mean age 9.2 years) which were diagnosed as suffering from navicular disease using predetermined criteria. The animals were used for a variety of purposes and had been lame for periods between 1 and 72 months. The majority of cases (84.7%) had been treated using various techniques before evaluation. The severity of lameness was related to the duration of clinical signs: 78% of horses were bilaterally affected but there was no left:right limb predominance. Broken foot/pastern axes were recorded in 75% of horses while 45% also exhibited mediolateral foot imbalance. Muscle atrophy was recognised in 77% of animals which appeared to be related to limb affliction. The cranial phase of the stride was reduced in 38% and caudal phase shortened in 16% of horses. These abnormalities were related to the degree of lameness. Flexion of the distal joints increased the severity of lameness in 64% of the animals while extension was positive in 41% of instances. Turning in the direction of the lame limb exacerbated lameness in 95% of horses. Only 11% of animals responded to the use of hoof testers and 3% to foot percussion. A range of responses to local analgesia of the palmar digital nerves was recorded but 91% (of 49) of animals exhibited a positive response to local analgesia of the distal interphalangeal joint, and 92% (of 23) of horses responded to local analgesia of the navicular bursa.