Congenital solitary osteochondroma affecting the tarsus in a filly foal

Arthroscopic removal of a solitary osteochondroma interfering with the podotrochlear apparatus in a foal

Objective

To report the diagnostics, surgical treatment, and outcome of a juvenile foal with solitary osteochondroma (SO) interfering with the podotrochlear apparatus.

Study design

Case report

Animal

One 36‐day‐old Arabian colt.

Methods

Clinical, radiographic, ultrasonographic, computed tomographic, and histopathologic examinations were required to characterize and treat an SO located at the palmar aspect of the diaphysis of the second phalanx of the left forelimb. This SO caused severe distal interphalangeal joint (DIPJ) inflammation, marked interference with the podotrochlear apparatus, and associated lameness.

Results

Despite the small size of the foal's foot, complete resection of the SO was possible via palmar DIPJ arthroscopy by using motorized equipment. Full resolution of the lameness was achieved within 3 months of surgery.

Conclusion

Atypical SO located on the palmar aspect of the second phalanx can cause marked nonseptic inflammation of the DIPJ and interference with the podotrochlear apparatus and should be considered among the differential diagnoses for severe lameness in juvenile foals. Arthroscopic resection of the SO led to an excellent outcome.

Radiographic Description of a Bone Exostosis Lesion on the Caudal Aspect of the Proximal Tibia in Three Thoroughbred Yearlings (2014-2019)

This manuscript describes exostosis lesions originating from the caudal aspect of the proximal tibia identified in three Thoroughbred yearlings as part of the routine review of presale radiographic images. These lesions are hypothesized to be osteochondromas. The identification of bony exostoses on the proximal tibia has not been reported before in current literature. As they have not been described, the future effect on performance or soundness is unknown. Although these cases were not lame at the time of detection, the future growth of the lesion and its impact on surrounding soft tissues is unknown.

Osteochondroma of the First Phalanx in Tbourida Horses

This study aimed at describing anatomo-histopathological and imaging features, using computed tomography and magnetic resonance imaging on six ex vivo forelimbs of Tbourida horses, that presented a particular bone exostosis on the dorsal and proximal part of the first phalanx, diagnosed by X-ray. Gross anatomy of the bone exostosis revealed an irregular surface with poly-lobulated tissue masses showing a cauliflower shape. The diameter/depth varied from 0.5 to 5.1 cm with a mean of 3.9 ± 0.9 cm. The capsule of the metacarpophalangeal joint was hypertrophic and showed many invaginations in the inner part, in contact with the bone exostosis. Computed tomography revealed cortical and medullary continuity of the bone exostosis, with the underlying bone, and remodeling of the cortical surface of the dorsal and proximal part of the first phalanx. Magnetic resonance imaging showed an increased signal intensity of the bone exostosis on the T1- and T2^*-weighted gradient fast echo. Histological examination of the bone exostosis revealed a cap of hyaline cartilage, including large foci of endochondral ossification with a base of cancellous bone surrounding marrow spaces, which confirmed the diagnosis of osteochondroma. The capsule of the metacarpophalangeal joint showed a large amount of recently formed connective tissue fibers in its inner part, interspersed with mature connective tissue. The hyperextension of the metacarpophalangeal joint during a Tbourida show, which occurs on a hard ground surface, and the use of hobbles in horse stabling are most likely responsible for the outgrowth of an osteochondroma of different shapes and sizes, and fracture complications in some cases.