Also Known As

Compressional phystitis


Epiphysitis is a condition involving rapid growth of the bone structure in young horses. Often referred to as compressional physitis, it may result in growth defects and cause pain. The condition is closely related to contracted tendons.

Affected foals are usually taller than their herd mates or may be foals that are maturing very quickly because of high protein feed. Epiphysitis is the result of rapid bone growth that results in inflammation and swellings on the inside of the fetlock and knee joint.

This inflammation of the epiphysical cartilage plate of the long bones usually occurs in the front legs and is caused by excessive pressure from too much weight or too much concussive force on the undeveloped skeletal structure.


  • Lameness
  • Swelling and inflammation of the fetlock and knee joint
  • "Hour-glass" appearance of knee and ankle joints


The causes of epiphysitis or compressional physitis are related to structural changes in the physis or growth plate of the bone brought on by rapid growth, concussive pressure, and/or a too-rich protein diet. Foals with pre-existing angular limb deformities and weanlings or yearlings with straight legs are prone to this condition.


Since the condition affects foals with pre-existing angular limb deformities and weanlings or yearlings with straight legs, attention needs to be given to proper diet, proper exercise, and careful hoof trimming based on a veterinarian's advice.


Treatment of epiphysitis includes maintaining a proper diet for young foals that includes reducing food intake and making sure the diet is not too rich in proteins or calories that cause the foal to gain weight too rapidly.

Anti-inflammatories and other treatments may be recommended by a veterinarian to provide pain relief and enable the foal to engage in proper exercise. Keeping the hoofs properly trimmed to support the growing bone structure is also helpful.

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