Radiological development of osteochondral changes in the fetlock and tibiotarsal joints of foals.

In 1997 and 1998 the fetlock and tibiotarsal joints of 130 warmblooded foals were examined radiologically. The foals were x-rayed monthly until they were weined, regarding especially the beginning and development of osteochondral changes and osteochondrosis dissecons. First signs of osteochondral variations, such as irregularities and low density of bone margins, were seen in an early age of under one month in the fetlock and tibiotarsal joint. "Joint mice" developed from those early changes, in the dorsal aspect of the fetlock joint during the fourth month of life, in the palmar/plantar aspect of the fetlock joint between the second and fourth month, at the distal part of the tibia in the fourth month, and at the lateral talus in the fourth month, too. In single cases, joint bodies developed earlier. They were not seen in neonatal foals. In the region of the proximal sesamoid bones isolated ossification centres were seen.