Bony fragments in the tarsocrural and metacarpo- or metatarsophalangeal joints in the standardbred horse--a radiographic survey.

Radiographic examination of the tarsocrural, metacarpo- or metatarsophalangeal joints was made in 139 Standardbred horses. Most were under three years old with no history of orthopaedic problems. In the tarsocrural joint, osteochondrosis was observed in 25 (18.1 percent) of the horses (n = 138) and 14 (56 percent) of these were affected bilaterally. In the metatarsophalangeal joint, the most frequent radiographic abnormality was single or multiple bony fragments or defects at the plantar proximal end of the proximal phalanx, which was noticed in 40 (28.8 percent) of the horses (n = 139). The lesion was much more frequent in the hind than in the forelimbs. Ten percent of horses affected in the hindlimbs had the lesions bilaterally. Palmar or plantar fragments wee also more common in the medial, than the lateral, part of the joint. With regard to osteochondrosis in the tarsocrural joint and palmar or plantar bony fragments in the metacarpo- or metatarsophalangeal joints, no significant differences in incidence were found between sexes or between left and right sides. There was no correlation between findings of osteochondrosis in the tarsocrural joints and the occurrence of bony fragments in the plantar part of the metatarsophalangeal joints. In the forelimbs, bony fragments in the dorsal parts of the metacarpophalangeal joint were noticed in three (2.9 percent) of the horse (n = 103) and the corresponding figure for the metatarsophalangeal joint was three (2.2 percent) (n = 139). In 102 horses, the tarsocrural, the metacarpo- and the metatarsophalangeal joints were radiographed at the same time. One or several joints were affected with osteochondrosis, bony fragments, or defects in underlying bones in 45 (44.1 percent) of these horses.