What is a hygroma?
A hygroma is a false bursa, which is a nonpainful, fluid-filled swelling surrounded by a thick, fibrous capsule that develops under the skin. Hygromas most commonly develop on the outside of the elbow. They can also occur on the hip and hock. Hygromas are initially small, soft, and fluctuant and do not pose a problem for the dog. They may be present for the dog's life time. In some instances, they may become quite large, up to 2 inches in diameter, or very hard. Hygromas can become infected in which case they are painful, sometimes warm to the touch, and may develop draining tracts.
What causes a hygroma?
A hygroma is caused by repeated trauma to an area over a bony prominence. The trauma most often occurs as a result of lying on hard surfaces, such as cement or hardwood floors. It is more common in larger breed dogs in which more weight is placed on the bony area having contact with the hard surface. Hygromas are also more common in dogs that are sedentary, such as those recovering from surgery or having other medical conditions that make them less active (e.g., hip dysplasia).
How is a hygroma treated?
The first step in treatment is to prevent further trauma. This can be accomplished by providing a soft padded bed. The area involved can be bandaged using donut-shaped padding over the elbow, placing the 'hole' of the donut over the hygroma. This will protect the hygroma from further contact with anything hard. Simply bandaging the area is often not effective since there would still be pressure on the hygroma if the dog lies on that side. There are commerical products available for protecting the elbows and for dogs with hygromas. Try searching for "dog hygromas" on the web.
Periodically aspirating (removing the fluid via needle and syringe) the hygroma is usually not effective and may introduce infection. Likewise, surgery is seldom performed unless the hygroma is infected. Generally, the area involved is so large that once the hygroma is removed, skin grafting or other techniques may be needed to close the incision. When the animal flexes and extends the leg, considerable tension is placed on the sutures and the incision is likely to open up. Some success has been seen by surgically inserting a drain (latex tubing) into the hygroma to allow for constant drainage. Then the area is bandaged, and the dressings are changed regularly.
How can a hygroma be prevented?
Hygromas can be prevented by providing soft bedding, especially beds made of orthopedic foam. Animals recovering from surgery should be turned from side to side multiple times during the day.