The term elbow dysplasia (ED) is a general term that is used to describe a developmental degenerative disease of the elbow joint (abnormal development of the elbow joint). The elbow joint is formed by three bones, the humerus, ulna and radius. It is believed that for normal joint development the three bones must develop at a synchrony so a normal joint shape maintained. Problems in growth synchrony is to blame for abnormal development, pain and arthritis of the elbow joint. Elbow dysplasia is commonly a bilateral disease, which means both elbows may be affected.
This disease has created considerable confusion and controversy not only on the part of dog owners, but with practicing veterinarians as well as researchers who are studying the problem. While our ability to diagnose ED has improved in recent years, there is still a great deal to be learned about its causes, prevention, and what constitutes appropriate treatment.
Most commonly, ED affects the large and giant breeds, although other breeds can be affected. With age arthritis begins and progresses for the life of the dog. Severe arthritis also causes soreness, which usually occurs in the older dog who may have had problems as a puppy or who never showed any previous signs at all. Arthritis develops due to the body’s response to inflammation and elbow incongruence (luck of fitness of joint components). The most notable changes that occur are the progressive thickening of the tissues around the joint and the production of bone around the joint surface.
CAUSES OF ED
The specific mechanisms which cause ED are not known. Genetics certainly plays a role, however, the specifics of how the disease is passed from one generation to the next, is very-complex and not completely understood. For example, puppies born from a breeding pair with ED, although more likely to have the disease, may be completely normal. Similarly, normal breeding pairs, although more likely to have normal puppies, may produce offspring with severe ED. This complexity with regard to genetics has frustrated efforts to eliminate the disease completely, and has led people to believe that environmental factors are responsible for disease expression, as well.
Nutrition and growth rate are considered to be important environmental factors related to ED. There is strong evidence, from a number of studies, that dogs who are overfed, and gain weight too rapidly, are predisposed to ED. This seems to be most important for large or giant breeds in the first 6 months of life. There is good evidence suggesting that puppies who grow more slowly have less chance of acquiring ED. Feeding premium puppy-foods, ‘free-choice’ to puppies, is not recommended, especially with large breed dogs, Additionally, providing vitamin or calcium supplements, is not recommended for puppies who are fed a balanced nutritionally complete dog food. Most reputable dog foods, even those for adult dogs, have all the vitamins and minerals puppies need.
SIGNS AND SYMPTOMS
Dogs with ED may or may not be lame, therefore, using lameness alone to determine its presence may result in misdiagnosis. Dogs with clinical ED typically develop foreleg lameness between the ages of 5 and 18 months of age, however, in some cases the lameness may not be apparent until as late as 5-7 years of age. The lameness may be variable and periodic. Some dogs may demonstrate soreness after rest, improve slightly with activity, but then worsen with increased activity. There may be intervals with no lameness at all. Jumping and sharp fast turns usually exaggerate the lameness. Pain can be elicited by over extending or over flexing the elbow, and there may be a slight to moderate swelling noticeable when carefully feeling the elbow joint. If both legs are meaningfully affected the lameness may be more difficult to detect. Careful observation would show slight rotation of the top of the paws outwardly, as well as a stiff or stilted movement of the forelegs. There may be reluctance on the dog’s part to land hard on the front legs (e.g. trotting, loping or landing jumps). Understanding the symptoms and causes of ED is extremely important if informed decisions are to be made regarding diagnosis, treatment, and prevention of ED.
DIAGNOSIS
Diagnosis of ED consists of history, clinical signs, thorough orthopaedic examination and radiographs (x-rays).
TREATMENT
Conservative Treatment
Conservative therapy has three-major components:
- Weight control
- Use of anti-inflammatory and other drugs
- Exercise control
Weight control is extremely important. Obesity causes excessively high forces to be transmitted through already abnormal joints. Soreness may be exacerbated, and arthritis accelerated, in dogs that are overweight. The appropriate weight and diet program for your dog can be obtained from your veterinarian or from a veterinary nutritionist.
Anti-inflammatory medication is an important part of conservative therapy especially when soreness flares up. DO NOT treat your dog yourself. Drugs such as Aspirin, and Ibuprofen can be extremely toxic to dogs when given an incorrect dose. The metabolism and dosages of some drugs are much different in dogs as compared to people.
Exercise must be controlled for conservative therapy to be effective. “Full-out” running, jumping and rough housing should be avoided. When soreness flares up, exercise should be extremely limited for a few days. Some owners mistakenly believe that their pet knows his or her own limits, and will restrict themselves as needed. In general this is not true. It could be argued that many people don’t recognise their own limits, and will ‘over-do-it’ exercising, even though they’re likely to regret it the next day. Most dogs are like these people. If allowed, they will run, jump or play to their fullest ability, even though they are likely to re-injure themselves.
Surgical management
The most common surgical objectives for the treatment of ED are to remove the offensive cause or the source of pain from the elbow and correction of the abnormal developed joint when indicated. These objectives are usually reserved for the younger dogs that still have a joint worth saving.
The prognosis for surgical management worsens with age and with advancement of arthritis. For this reason it is extremely important to have regular check ups, which includes history taking, general physical examinations and thorough orthopaedic examinations during the early months of the dog’s life.