Osteochondritis dissecans (OCD)

Veterinary advice should be sought before applying any treatment or vaccine.

Osteochondritis Dissecans (OCD)

Osteochondritis dissecans (OCD) is a common type of developmental orthopedic disease (DOD) in which the diseased cartilage has separated from the underling bone, within one or more joints. OCD most commonly affects young, rapidly growing warmblood-type horse breeds.

OCD of the Stifle joint


Horses are most commonly affected by OCD of the stifle (femoropatellar) joint. Approximately 60% of horses that are affected by this condition are one year of age or less at the time signs develop in affected horses. Horses with OCD of the stifle joint often have a history of a recent increase in the level of athletic fitness training. The typical signs are a sudden onset of joint swelling and mild lameness. Lameness is usually associated with a shortened stride and stiff leg action. When horses are more severely affected, they may develop a 'bunny hop-like' gait which can sometimes confuse owners into thinking that the horse has a neurological problem. Thoroughbreds are most frequently affected by OCD of the stifle joint.

OCD of the Hock joint


OCD of the hock (tarsocrural) joint is most commonly seen in Standardbreds, although all breeds can be affected. Clinical signs of this condition manifest as Bog spavin, which is a prominent swelling that develops along the inner part of the horse's hock joint. Lameness may also be present in some horses, however it is usually mild. Although lameness may only be mild initially, if the condition goes untreated, it often becomes a problem later in life which limits their ability to perform at upper levels or at racing speeds. Surgery early in the horse's life is considered the best treatment, and is associated with the most positive prognosis. Once degenerative changes begin to occur, as a result of the lesions, the prognosis for the horse decreases with respect to their athletic career.

OCD of the Shoulder Joint


The shoulder joint is one of the least common joints affected by OCD in horses, however when it does occur it is the most debilitating type of OCD. This is because it often involves a large portion of the joint surface, and accompanied often by secondary joint disease. Signs usually develop in horses when they are about one year of age or younger. These horses will usually have a history of forelimb lameness, sometimes with muscle atrophy. Because horses will modify their gait as a result of the pain, they often develop uneven feet, with one foot appearing club-footed, and the foot may look smaller then the other. Any pressure exerted in the shoulder area will cause the horse discomfort. The changes of a favorable outcome for horses to perform well athletically with OCD of the shoulder joint is quite low, however the chances improve if the horse has had surgery early on, when the signs first present.

Symptoms

Effusion (swelling) in the joint
Lameness
Stiff gait

Diagnosis

  • History
  • Clinical signs
  • Physical exam
  • Radiographs - Since OCD is often bilateral, radiographs of the opposite joint are usually indicated, even if there is little to no swelling present in that joint.
  • Lameness exam
  • Ultrasound

Treatment

TherapiesDetails
ArthroscopySurgical removal of the abnormal bone and cartilage by making two or more small (less than 1 cm) incisions into the joint through the use of an arthroscope (a tiny camera) and other special instruments. This procedure is performed by an ACVS board-certified veterinary surgeon. It is preferred over another type of surgery called an arthrotomy, which requires surgeons to make a large incision into the joint which results in more surgical trauma and risk.
ArthrotomyAnother type of surgical procedure used for removal of OCD fragments, however it is done through surgeons making a large incision into the joint, as opposed to small incisions as conducted in an arthroscopy.

Prevention

  • Provide young horses with appropriate mineral supplementation.
  • Young horses should have restricted exercise and a reduced diet to slow growth rate.

Prognosis

Good to excellent if recognized early and treated surgically

Scientific Research

General Overviews

Risk Factors

  • Nutrition : High-energy Or Low Copper Diets
  • Rapid Growth And Large Body Size
  • Trauma And Exercise: Acute Or Recurring Trauma And Even Routine Exercise Is Frequently Associated With The Formation And Loosening Of The OCD Flap.
  • Genetic Predisposition
  • Hormonal Imbalances: Insulin And Thyroid Hormones