Osteochondrosis dessicans (OCD) and subchondral cystic lesions (SCL)
This condition is developmental and occurs in younger animals. It is usually associated with high growth rates and excessive energy intake.
The condition occurs as a small area of cartilage in the joint fails to calcify to bone, as the animal grows, and becomes thickened. The deeper portion of this thickened cartilage then dies (chondrolysis). This area may either leave a persistent weak point in the cartilage, often leading to further damage later on (OCD), or form a subchondral cystic lesion (SCL) as the dead region of cartilage remains in the bone leaving the rest of the bone and joint to develop normally. The path taken seems to depend on the exact site involved. Lameness can vary to no lameness whatsoever to a severe lameness. Degenerative joint disease (DJD) can develop as a secondary complication of the condition.
Diagnosis
X-rays are required for diagnosis and to assess treatment options.
Treatment
Initially treatment is aimed at reducing the growth rate of the animal by reducing feed intake and box rest for up to one year. There are also mineral supplements available that may aid in the treatment. In many cases, however, the damaged portion of cartilage must be removed surgically using arthroscopy (key-hole surgery).