Clinically OCD is seen as mild synovitis in multiple joints with mild, lameness that does not improve with exercise. Radiographically, OCD is seen as flattening of the articular surfaces of the affected joints. Large, collapsed bone cysts may be noted on radiographs. Arthroscopic exploration of an affected joint will reveal fissures and flapping of the articular cartilage. If present, joint mice may be viewed either arthroscopically or radiographically.
Diagnosis can be made through clinical signs and symptoms as well as through radiograph and arthroscopy.
Treatment of OCD depends on the severity of the articular changes. For mild cases, and a controlled exercise program may be implemented until the horse is fully developed. In more severe cases, IA corticosteroids or Adequan may be combined with rest and a controlled exercise program. In cases where cartilage flaps or joint mice have developed arthroscopic surgery is necessary to the joint. It may be necessary to wait until the horse is fully matured before arthroscopic debridement occurs. Once the surgery site has healed the horse should be put on a controlled exercise program. It is not recommended to breed individuals affected by OCD as it, like all other DOD’s, is thought to have a genetic predisposition. Modifying the diet of broodmares and foals may help reduce the risk that a DOD will develop. Physeal Dysplasia Physeal dysplasia is the result of a defect in the physis, or , of a long bone that causes a failure in the endochondral ossification normally seen during long bone growth. Also called physitis or epiphysitis. Physeal dysplasia is considered a developmental orthopaedic disease that usually occurs due to mechanical compressive stress on the physis causes compression and subsequent necrosis of an area of the physis. The necrotic lesion causes localized inflammation which disrupts the integrity of the surrounding bone, causing micro-fractures. The lesion also fails to ossify in a normal manner, resulting in retarded bone formation. Physeal dysplasia is seen in foals less than two years of age and is seen more commonly in those performing high impact exercises. Individuals with poor limb conformation have a higher risk of developing physeal dysplasia as there is generally more concentration of force on a single aspect of the limb. Physeal dysplasia is most commonly seen in the physis of the third metacarpal at an age of four to six months, and in the distal physis of the radius at an age of twelve to twenty months. Tibia and metatarsus is also commonly affected. Clinically physeal dysplasia is seen as an area of firm swelling that is warm and painful to palpate. The joints near the affected physis appear enlarged and boxy, and lameness is seen in the affected limb(s). Angular limb deformities often result. Radiographically, physeal dysplasia is seen as a physeal flare and micro-fracture may be seen in the surrounding bone.
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