OCD lesions are cartilage flaps (sometime containing bone) that develop at the end of bones during the development of young horses. This condition is most common in young horses that experience rapid growth spurts.
As the soft cartilage cells at the end of bone turn into bone cells, effectively lengthening the bone, sometimes the process goes askew and the cartilage pulls away from the bone, resulting in cartilage flaps (OCD lesions). These flaps add a secondary concern when they break loose and find their way into the joint, also known as “joint mice.”
OCD lesions are most commonly found in the stifle, hock and fetlock joints as well as between the neck vertebras. Lesions can also occur, although less commonly in the shoulder, hip and elbow joints. The lesions cause inflammation and fluid buildup resulting in varied levels of lameness. Over time, if the condition is left untreated, the affected joints can develop degenerative joint disease (arthritis).
OCD lesions will generally develop within the first 11 months of life but may not be noticed until 3 to 5 years of age as the horse begins training. If you are considering the purchase of a young horse, it is a good idea to radiograph those joints that are most affected to determine if OCD lesions are present.
Learn More: Treating OCD Lesions in Horses