First phalanx exostosis in traditional equestrian horses in Western Libya

Abstract

Background: Orthopedic diseases involving the forelimb fetlock joint of horses other than those used in professional racing have not been widely reported in the literature. One of these problems is the exostosis on the proximal forelimb phalanx (P1), which has not been reported previously in Western Libya.

Aim: The study aimed to investigate the prevalence of P1 exostosis in traditional equestrian horses (known locally as Sarj horses) of different breeds in Libya that participated in a special social event and described its clinical findings radiographic appearance.

Methods: The current study involved 60 horses admitted to private veterinary clinics with varied fetlock orthopedic problems. The studied horses were aged between 6 and 11 years old and galloped on hard grounds. Clinical and radiographic examinations were carried out on all horses. Lateromedial radiographs for one or both forelimb fetlock joints were acquired for each horse.

Results: Clinical examination revealed that 21 horses (35%) had hard non-painful swelling on the dorsal aspect of fetlock with joint stiffness during flexion. In 19 of them, the swelling was bilateral. No forelimb lameness was noticed. Radiographically, hard swelling was diagnosed as bone exostosis, with various sizes, on the proximo-dorsal aspect of P1. There was also a new bone formation on the disto-dorsal part of third metacarpal bone in two cases.

Conclusion: This study has documented the first report on bone exostosis on the proximo-dorsal aspect of the forelimb proximal phalanx as a common problem in Sarj horses that galloped on hard grounds in Western Libya. Although this bone lesion did not cause lameness in all reported cases, further investigations are warranted to identify its histopathological nature, potential etiology, and proper treatment.

Keywords: Exostosis; Fetlock; Forelimb proximal phalanx; Horse; Radiography.

Fig. 1.. Sarj horses presented with a fetlock joint swelling. (A) Photo shows dorsal swelling involving the fetlock region bilaterally. (B) Photo shows the fetlock joint stiffness during the flexion test.

Fig. 2.. Distal limb radiographs for Sarj horses presented with hard swellings involving the dorsal aspect of the fetlock region. (A) Lateromedial view of forelimb fetlock shows small new bone formation on the dorso-proximal part of P1. (B) Lateromedial radiograph for another horse with a larger dorsal P1 exostosis. P1: first phalanx.

Fig. 3.. Radiographic findings in two different Sarj horses with forelimbs P1 and Mc3 bone exostosis. (A) Lateromedial radiograph shows a new bone formation involving the dorso-proximal P1 and disto-dorsal Mc3. (B) Lateromedial radiograph a new bone formation involving the dorso-proximal P1 and the disto-dorsal Mc3. There are multiple bone fragments close to the newly formed bone lesions, which seem to be from the lesion. P1: first phalanx bone; Mc3: third metacarpal bone.