Enostosis-like lesions in the long bones of 10 horses: scintigraphic and radiographic features.

This study investigates the characteristics of enostosis-like lesions in the long bones of ten horses experiencing lameness. Using scintigraphy and radiography imaging, the researchers identified the lesions, evidence of which were seen as increased radioisotope uptake or radiopacities in the medullar cavity of long bones. Despite being a plausible cause of lameness in half of the cases, these lesions were seen as incidental findings in the remaining horses. Finally, the lameness resolved following rest and medication in some horses, with subsequent scans revealing normal radioisotope levels in affected areas.

Study Subjects and Test Animals

• The study involved ten horses that were brought in due to issues with lameness. These horses underwent bone scintigraphy to help diagnose their condition.
• A particular focus of this study was on enostosis-like lesions, which were found in the long bones of the animals.
• The breed makeup of the study group included six Thoroughbreds (one each of male and female, four geldings), three Standardbred geldings, and an Appaloosa gelding.
• The horses ranged in age from three to ten years old.

Findings of the Research

• Enostosis-like lesions were discovered in various long bones, including the tibia (seen in 5 horses), radius (3 horses), humerus (one horse), and third metatarsal bone (4 horses).
• The number of bones affected in each horse ranged from one to three.
• Of the sixteen limbs with the lesions, nine were hindlimbs, and seven were forelimbs.
• In five of the horses, the lesions were considered a potential cause of the experienced lameness. However, in the rest of the horses, the lesions were deemed incidental findings, not directly causing the lameness.

Treatment and Follow-up

• Four of the horses were treated with nonsteroidal anti-inflammatory drugs, and all horses were given a period of rest, ranging from two to six months.
• Follow-up scintigraphic tests were conducted in three of the horses at various intervals (2, 6, and 9 months after initial diagnosis).
• These follow-up tests revealed the radioisotope uptake in the areas previously affected by lesions had returned to normal. This indicated an overall reduction or resolution of the lesions post-treatment.
• The study therefore suggests that with appropriate treatment and sufficient rest, horses facing lameness due to enostosis-like lesions in long bones can effectively recover.