A study of 118 cases of navicular disease: clinical features.

The research article discusses a study conducted on 118 horses diagnosed with navicular disease. Predetermined criteria were used to diagnose the horses, and the aim was to understand the clinical features of the disease in these animals.

Participant Information

• The horses in the study ranged in age, with an average of 9.2 years. They were used for various purposes and had all been diagnosed with navicular disease.
• The time the horses had been lame varied between 1 month and 6 years.
• Before the evaluation for the research, 84.7% of horses had already been treated using different methods.

Clinical Features

• The lameness severity seemed to be related to the duration of clinical signs.
• In this study, 78% of the horses had bilateral affliction, meaning they were affected on both sides, but no prominent left or right limb predominance was observed.
• Broken foot/pastern axes were found in 75% of the horses. The foot/pastern axis represents the angle that the overall limb makes with the ground, from the fetlock (a joint of a horse’s leg) to the pastern (the part of a horse’s foot between the fetlock and hooves).
• About 45% showed mediolateral foot imbalance, referring to an imbalance in the width distribution of the foot from the middle to the sides.
• Muscle atrophy, or loss of muscle mass, was observed in 77% of the horses. This appeared to be linked to the afflicted limb.
• The stride’s cranial phase (forward movement) was reduced in 38% horses and the caudal phase (backward) was shortened in 16%. These abnormalities seemed to be related to lameness severity.
• Flexion, or bending of the distal joints, increased the lameness severity in 64% of the horses, while 41% showed an increase in lameness with extension.

Response to Pain and Treatments

• The majority of the horses (95%) showed exacerbated lameness when turning in the direction of the lame limb.
• Only a small percentage of horses (11%) responded to the use of hoof testers, and an even smaller 3% responded to foot percussion. Both these methods are used to identify a source of lameness.
• In contrast to these minimal responses, a range of reactions to local analgesia of the palmar digital nerves was noted. In particular, 91% of horses showed a positive response to local analgesia of the distal interphalangeal joint and 92% responded favorably to analgesia of the navicular bursa. Both these methods numb the area to alleviate pain and discomfort.