Peer-reviewed veterinary case report
Synostosis of the first and second ribs in six horses.
- Journal:
- Journal of the American Veterinary Medical Association
- Year:
- 2018
- Authors:
- Rovel, Tibor et al.
- Species:
- horse
Plain-English summary
Over a two-year period, six horses, including four Selle Français, one Hanoverian, and one Thoroughbred, were examined for front leg lameness. All of them had a condition called synostosis of the first and second ribs, where these ribs are fused together. In one horse, this rib issue was likely causing a moderate lameness, while in three others, it was thought to possibly contribute to mild lameness. Two horses had this rib condition but showed no signs of lameness at all. The horse with the most severe lameness was retired and remained chronically lame, while two of the horses that received treatment returned to competing but did not perform well. Overall, the treatment had mixed results, with some horses improving and others not.
Abstract
CASE DESCRIPTION Over a 2-year period, 6 horses (4 Selle Français, 1 Hanoverian, and 1 Thoroughbred) were referred for evaluation of forelimb lameness. All horses had radiographic evidence of synostosis of the first and second ribs (SFSR). CLINICAL FINDINGS For 1 horse, the SFSR was considered the probable cause of the lameness (grade 3/5), with a shortening of the cranial phase of the stride in the affected limb. For 3 horses, it was considered a possible cause of the lameness (grade 1/5) for the same reason. For 2 horses, SFSR was considered an incidental finding unassociated with any clinical signs. The 4 horses with lameness suspected as attributable to SFSR had a moderate to severe amount of irregularly marginated new bone formation at the site of the SFSR, with a cranial displacement of the first rib, compared with findings for the 2 horses in which the SFSR was considered incidental. A likely congenital abnormality of the first rib was first suspected on nuclear scintigraphy in the 1 horse for which it was performed or on radiography of the caudal cervical portion of the vertebral column (3 horses) or shoulder joint (2 horses). TREATMENT AND OUTCOME The horse in which SFSR was considered the probable cause of the lameness was retired to the field and remained chronically lame. Two of the 3 horses in which SFSR was considered a possible cause of lameness received an IV infusion of tiludronate disodium and mesotherapy over the caudal cervical and cranial thoracic regions; both returned to competition but with poor results. One of the 2 horses with subclinical SFSR never developed lameness on the affected side. No follow-up information was available for the other 2 horses. CLINICAL RELEVANCE SFSR can be an incidental finding in horses, with or without clinical manifestations. This abnormality should be considered as a differential diagnosis for horses with forelimb lameness and associated shortening of the cranial phase of the stride that fails to improve with diagnostic analgesic techniques.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/30110211/