Swollen Fetlocks in horses.

Most horses will present with swollen fetlock/s at some stage of their life. On the majority of occasions it will be a temporary situation but to some a recurring, even deteriorating condition.
Temporary incidence could be a result of:

(1) A wound infecting the skin area. An abrasion or cut resulting in a local infection. A course of antibiotics usually clears this up in a week or so.

(2) Severe lower leg impact causing bruising. The application of a cream or gel will dissipate this. Running cold water over the area, and some exercise both help as well.

(3) A sprain as a result of stepping wrongly. An anti-inflammatory (such as bute), and ceasing work generally sees an improvement within a week.

(4) Greasy Heel. Extent of treatment depends on severity. See my article on Greasy Heel.

(5) Minor Hoof problem - An elevated pulse to the hoof will give the impression of a swollen fetlock. Fix the hoof problem and the pulse returns to normal.

Recurring and/or deteriorating conditions include:

(a) Tendonitis of the extensor tendons - Soft tissue injuries to the deep digital flexor tendon or suspensory ligaments

(b) Passive or active edema of the subcutaneous tissue overlying the joint.

(c) Lymphangitis (normally in a hind leg fetlock). A rare chronic fungal disease in which lymph vessels contain granulating abscesses and are grossly dilated with pus.

(d) Major Hoof problem - Navicular Disease, Fracture of the Pedal/Coffin bone, Laminitis or Founder.

(e) Degenerative Joint Disease (DJD) This term is used to describe the deterioration ( or pitting ) of joint cartilage. This occurs predominantly in fetlocks and knees, but can also occur in pasterns and hocks/stifles. Various stages of this disease would account for the greater percentage of swollen fetlock causation.

Fetlock joints, which allow considerable movement, are known as synovial joints. They possess a joint cavity which contains fluid allowing the bones to slide over one another without grinding and causing pain. The cavity of the joints are lined by a membrane which is responsible for the production of the thick, syrupy lubricating fluid.

Synovial joints also contain articular cartilage, which cover the ends of the connecting bones. Cartilage is a thick pad of tissue that absorbs the force of flexion of the joint. It has no blood supply and is unable to heal itself if damaged.

Horses subjected to continual, strenuous exercise place constant stress on the joints, which cause them to become inflamed. As inflammation intensifies within the joint the lubricating ( synovial ) fluid dilutes into a thin and watery state, becoming less effective in protecting the cartilage. This, accompanied with the cartilage becoming frayed and rough as a result excessive compression associated with speed and/or jumping, leads to pitting of the cartilage.

Before DJD occurs, the initial sign of joint disease displays as inflammation of the synovial membrane - called synovitis. Apart from strenuous exercise, other contributing factors include hard, unforgiving working surfaces, poor conformation and bad shoeing. Synovitis manifests as windgall - pockets of fluid around the joint as joint fluid production increases in response to the inflammation.

Thoroughbred racehorses routinely suffer from this condition. Rest and/or treatment will generally alleviate the problem but if ignored and a demanding exercise regime continues unabated, damage to the cartilage will inevitably begin.

Treatment of DJD depends on the severity of the disease and the level of exercise the horse is required to perform. In the initial stages, stable rest and ice boots will more than likely be sufficient to reduce the swelling and inflammation. In more established cases analgesic and anti-inflammatory medications are normally required. However, although these medications remove the pain, they do not cure the condition.

The bottom line is consult your veterinarian if you cannot establish the cause of the swelling is minor and temporary.