Elbow Dysplasia

Elbow Dysplasia is a cause of front leg lameness in young dogs. Elbow dysplasia is a complex of at least 3 diseases of the elbow that commonly causes front-leg lameness in young dogs, sometimes as young as 4 months of age. If your dog develops a front leg lameness at a young age it is very important to get a complete diagnostic work up to determine if elbow dysplasia could be the cause. It is easy to mask the symptoms with anti-inflammatory drugs, which makes it look like the problem has gone away, only to surface years later with severe arthritis in the elbow.

Early Diagnosis of Elbow Dysplasia
Initial diagnosis should include a complete gait analysis, physical exam and high quality x-rays, with at least 3 views taken. Localization of pain to the elbow in a young dog is highly suspicious of elbow dysplasia even if plain x-rays appear normal. Diagnosis can be difficult and may require additional diagnostic tests such as CT (computerized tomography - 3D x-ray) and arthroscopy to diagnose. Our goals in diagnosis include identifying the presence of cartilage damage within the joint and understanding what is the likely cause. This enables us to be able to treat the disease more completely and try to prevent ongoing progression of arthritis most effectively. Early diagnosis is very important so that treatment can be as effective as possible in preventing the progression of elbow arthritis, which follows elbow dysplasia.

What is Elbow Dysplasia?

The elbow is the joint in the middle of the dog's front leg where three bones meet: the humerus, radius and ulnar. Illustrated in red, are the three locations of the most common forms of elbow dysplasia: UAP - ununited anconeal process, FCP- fragmented coronoid process, OCD - osteochondritis dissecans.

Development of Elbow Dysplasia:
The cause and the development of elbow dysplasia is still unclear but there are some emerging new theories which may be very helpful in understanding how best to diagnose and treat these conditions. It is believed that much of the damage to cartilage on the medial coronoid process may result from conflict between the humerus and ulnar during motion of the joint. This understanding is leading to the development and application of new procedures to restore the right relationship of humerus, ulnar and radius at the joint in addition to treating the cartilage damage itself with the arthroscope.

Treatment of Elbow Dysplasia:
The treatment of this complex of diseases includes both medical and surgical procedures. Again, it is important to stress early diagnosis so that the damage to the joint can be minimized. Once the elbow arthritis becomes advanced the chances of returning the dog to full function are much reduced.

Computerized Tomography (CT):
CT is basically three dimensional x-ray technology. It allows us to more accurately examine the orientation of the bones of the elbow and visualize fragmentation of the medial coronoid process without the overlap of other boney shadows on regular x-ray. In some dogs there is CT evidence of deeper disease of the coronoid that may not be visible on the cartilage surface even during arthroscopy.

CT images of the left and right elbow. The white represents the radius and ulnar bones beside one another. The small white fragments represent fragmented medial coronoid processes.

Elbow Arthroscopy:
Elbow arthroscopy is the cornerstone of both accurate diagnosis and treatment of elbow dysplasia at our clinic. A small (2.4mm) arthroscope is used to visualize the interior of the joint and accurately document whether there is a fragmented coronoid process (FCP) or osteochondritis dissecans (OCD) or both. It also allows an accurate grading of the degree of cartilage damage within the joint. In addition, damaged cartilage and bone can be removed without opening the joint surgically. Arthroscopy is minimally traumatic to the joint resulting in very little postoperative pain and additional damage to the joint. Dogs recover very quickly after arthroscopy and can usually go home the same day as the procedure or early the next day.

Addressing Elbow Mechanics and Restoring Elbow Congruity:
In addition to removing damaged fragments from within the joint, there is increasing emphasis on trying to understand what may have caused the damage to the cartilage in the first place. This may need to be addressed with ancillary procedures such as BURP (Biceps Ulnar Release Procedure) or UA (Ulnar Osteotomy).

Sliding Humeral Osteotomy -salvaging a badly damaged joint.

Sadly, cartilage deterioration can already be very advanced when we see your pet. This is especially true with older animals. Also, despite our best efforts, the cartilage can continue to break down and something further is required to keep your pet comfortable. Sliding humeral osteotomy is one of the options to treat badly damaged elbow joints. It works on a principle of weight transfer, used in people for many years. In many dogs with elbow dysplasia the damage to the cartilage is confined to the medial (inside) half of the joint. Sliding humeral osteotomy transfers the dog's weight over to the lateral (outside) half of the joint, thus relieving the pain on the inside of the joint. This is accomplished by cutting the humerus and transferring the bone laterally with a "stepped" bone plate. (see figure)

Complete elbow replacement (elbow arthroplasty) is also available in dogs but is still in its early stages of development. Elbow arthrodesis (fusion of the joint) also may be used as a pain relieving procedure but the functional outcome is quite poor. Sliding humeral osteotomy is showing great promise in relieving discomfort and maintaining function in those dogs with advanced elbow arthritis.

Un-united Anconeal Process (UAP):
This is a special case of elbow dysplasia and most commonly seen in the German Shepherd and is believed to be related to elbow incongruity. If the condition is diagnosed early enough, release of the ulnar via an ulnar osteotomy may be sufficient to resolve it. Otherwise the ulnar anconeal process may be fixed back with a special screw technique. In some cases, the UAP may be removed completely.

Ununited anconeal process

Un-united anconeal process treated with ulnar osteotomy and a lag screw

Medical Management of elbow arthritis:
Arthritis is a vicious cycle of disease. The joint consists of the soft tissue around the joint (the joint capsule), the joint fluid (secreted by the joint capsule) and the hyaline cartilage covering the bone within the joint (the joint fluid is responsible for lubrication and nourishment of the cartilage). In arthritis, the joint fluid is thinner than normal leading to increased wear and tear of the cartilage. This results in chemicals being released into the joint which further inflames the joint capsule resulting in thinner joint fluid, more cartilage wear, etc, etc.

Medical management of elbow dysplasia is really aimed at treating it's effects in causing elbow arthritis. Medical management can include one or more of the following and is often combined with surgical management:

• Weight Loss - being overweight puts great stress on diseased joints and weight loss can help considerably.
• Joint diet - there are commercial diets available that are rich in omega 3 fatty acids and other nutrients that help to minimize the inflammation within a diseased joint.
• Anti-inflammatory drugs - drugs that are related to the aspirin family are very effective in decreasing the inflammation within an arthritic joint. They can be used short and long term, but there use should be kept to minimum as they can have some serious side-effects if not used properly.
• Chondroprotective products - these products are protective of cartilage and are basically the nutrients that cartilage cells use to repair the cartilage structure. Glucosamine and chondroitin sulphate are the most commonly used such products. They have very few, if any, side effects and can be used long term in most patients except diabetics.

Prognosis for Treatment of Elbow Dysplasia:
Prognosis is significantly affected by how advanced the arthritis is in the elbow at the time of diagnosis. Hence early diagnosis is so important. Various studies have been done in the past comparing medical vs. surgical management of this condition with mixed results. In some cases, a lack of an accurate original diagnosis makes firm conclusions from these studies hard to reach. There have been some newer studies that have advanced our understanding of the disease processes in elbow dysplasia and the advent of the use of arthroscopy in veterinary medicine holds a lot of promise for improving outcomes in both the short and long term. Restoring elbow congruity effectively is another promising area of research.