Diet & Health

what is hip dysplasia?
The hip, or coxofemoral joint, is a ball-and-socket joint comprising a cup-shaped socket and the head of the thigh bone or femur, which is roughly spherical. These are held in place by soft tissues and, to some extent, the surrounding muscles. The term ‘hip dysplasia’ is used to describe hip joints which are loose and/or ill-fitting, many of which will develop osteoarthritis as the dog ages. In the young puppy, the skeleton is fairly soft and any laxity or incongruity of the hip joint will result in an abnormal conformation. As the animal matures, this abnormality becomes permanent as the skeleton hardens. Even following skeletal maturity (at about one year of age) abnormal stresses on the bones and soft tissues can continue to cause bony remodelling and the production of arthritic new bone.

How can hip dysplasia be diagnosed?
Certain clinical signs such as pain on rising or abnormal gait can lead to a suspicion of hip dsyplasia but it must be confirmed with an Xray. However, many dogs with hip dysplasia show no clinical signs until later in life, when arthritis has developed. If they have been used for breeding, hip dysplasia genes will have been passed to their offspring. The condition is a disease which is governed partly by genetic features and partly by environmental factors such as nutrition, bodyweight and exercise. Therefore, the radiograph simply records the physical end-result of a variety of causes and, at present, this is the best tool for screening dogs for hip dsyplasia. Although different assessment criteria are used in different countries, discussions between interested parties are ongoing in an attempt to provide some international standardisation.

How are hip radiographs taken?
Radiographs are taken when the dog is lying on its back with its hind legs extended and rotated inwards so that the thigh bones are parallel. The advantage of this position is that it can be reproduced consistently on different occasions, although a number of other projections may be employed to provide supplementary information. Sedation or general anaesthesia are necessary to allow accurate positioning without the need for the animal to be held. The radiographs must be identified accurately with the dog’s Kennel Club registration number, the date and a right/left marker.

What is the Kennel Club Hip Dysplasia Scoring Scheme?
In the UK an assessment scheme is run under the joint auspices of the Kennel Club and the British Veterinary Association (BVA). Dogs are radiographed by the owner’s veterinary surgeon and the radiographs are submitted to the BVA where each film is examined by 2 veterinary surgeons from its panel of expert scrutineers. Nine anatomical parameters are examined from each hip joint and allocated a score, ranging from 0 (perfect) to 6 (worst). The scoring scheme allows dogs within a breed to be compared with each other, and dogs should only be used for breeding if their hip score is well below the average score for that breed. It is also helpful to consider the hip scores of the parents, grandparents and siblings when selecting a dog or bitch for breeding. Dogs should only be used for breeding if their hip score is well below the average score for that breed.

What is elbow dysplasia?

Elbow dysplasia is a group of four slightly different diseases associated with abnormal development of this joint in puppies:

Fragmented medial coronoid process
OCD of the medial humeral condyle
Ununited anconeal process
Incongruity of the elbow joint

The most common form is fragmented medial coronoid process and this involves a small fragment of cartilage and bone loose within the joint that causes inflammation (arthritis).

What sort of dogs are affected?

Typically, the diseases causes lameness and pain in dogs aged 5-18 months. Certain breeds are particularly at risk for these disorders:

Fragmented coronoid process: Many medium to large breed pedigree dogs, but especially Labradors, Golden Retrievers, Rottweilers, Bernese Mountain Dogs, Bullmastiffs.
OCD: Many medium to large breed pedigree dogs, but especially Labradors, Golden Retrievers.
Ununited anconeal process: German Shepherd Dog, Bassett Hound

What causes these diseases?

The cause of elbow dysplasia is not fully understood. Certainly there is a complex genetic basis and it is likely that several different genes are involved. It is also likely that environmental factors (exercise, growth rate, nutrition) play a role.

What are the signs of these diseases?

All types of elbow dysplasia can cause pain and lameness although in some dogs the disease may remain clinically silent for many months or years. Lameness may appear suddenly or insidiously. Often the condition occurs in both elbows and so signs may relate to joint stiffness in both forelimbs. Later in life, the osteoarthritis initiated by elbow dysplasia may progress to cause pain, stiffness and lameness.

How are these conditions diagnosed?

A clinical examination by a veterinary surgeon is the first step in diagnosis. If elbow dysplasia is suspected, radiographs (x-rays) are the most usual initial step in making a diagnosis. Although some forms of elbow dysplasia may be obvious on radiographs, often there are only subtle changes, particularly early in the disease. However, radiographs only give limited information and a much more accurate assessment can be made with arthroscopy. This involves placing a small endoscope, linked to a video camera and monitor, in to the joint to examine the interior in a key-hole manner. Arthroscopy also provides the opportunity to remove the fragment in a minimally-invasive manner.

What can be done to treat the condition?

If causing persistent problems, fragmentation of the coronoid process is, in our opinion, best treated with arthroscopy. Removal of the fragment can relieve pain and allow improvement in joint function. OCD can be treated in a similar manner. Treatment of ununited anconeal process is more complicated but currently repair of the fragment with a corrective osteotomy below the elbow appears to offer the best option.

There are two cruciate ligaments in the knee joint, the cranial (or anterior) cruciate ligament and the caudal (or posterior) cruciate ligament. The cranial cruciate ligament is very commonly injured in dogs and this causes instability of the knee and may lead to other problems such as meniscal (cartilage) injury and osteoarthritis. It is rare for the caudal cruciate ligament to be injured.

Although in people, cruciate ligament rupture usually occurs during sports injuries incurred, for example, by skiers, soccer and rugby players, the situation in dogs is quite different. The cruciate ligament seems to weaken gradually in dogs, particularly in some larger breeds, and this means that the cruciate ligament may eventually rupture even during normal activity. Some large breed dogs can suffer cruciate ligament rupture from quite an early age (1-3 years) and often in both knees. Epidemiological evidence does indicate that certain breeds are at increased risk for cruciate rupture and these breeds include:

Labrador Retriever, Golden Retriever, Rottweiler, Mastiffs, Boxer, Newfoundland, West Highland White Terrier. However, many dog breeds can suffer from cruciate ligament rupture.

There is a suggestion that obesity also increases the risk of cruciate ligament rupture. This may be so, although further scientific information on this is required. Certainly avoiding obesity has been shown to reduce the severity of arthritis in other joints, so it seems to be sensible.

The cause of the gradual degeneration of the cruciate ligament is not known. However, recent research indicates that even "normal" ligaments from dogs at risk of cruciate rupture are weaker compared to those breeds at low risk. It appears that the ligament structure is altered such that it is unable to function as it should and is prone to failure. Research continues to elucidate the reasons for ligament degeneration.

Rupture of the cruciate ligament may occur suddenly or gradually and this can be reflected in the appearance of the signs of the condition which include lameness and stiffness of the knee. Full rupture of the cruciate ligament causes instability of the knee and this may lead to joint swelling and wasting (atrophy) of the muscles of the hindlimb, particularly the quardiceps muscle group. Dogs with cruciate ligament rupture often prefer to sit with the affected limb straightened out in front of them rather than tucked up; this is because they do not like to flex the knee.

A clinical examination by a veterinary surgeon is the first step in diagnosis. If cruciate ligament rupture is suspected, further tests may be required, including x-rays, joint fluid analysis, arthroscopy, MRI, or exploratory surgery. Once the cruciate ligament is ruptured, about 40-60% of knees will also develop injury to one of the cartilages of the knee. Osteoarthritis will develop in all knees with cruciate rupture, but may not cause problems for many months or years.

If causing persistent problems, and especially in larger dogs, the condition is best treated with surgery to stabilise the knee. There are many different surgical techniques for treating the condition and even specialty surgeons disagree regarding the best option. There is a lack of good scientific data to guide the surgeon and pet owner and surgeon preference for a particular technique is an important factor. Some of the common surgical techniques used to treat the condition include:

There is no agreement as to which is the best technique. Recent data would suggest that if there are differences between the techniques, these are minimal.

In the long run, all joints with cruciate ligament rupture will develop some degree of osteoarthritis. However, for most dogs the response to surgery is good and the osteoarthritis does not seem to cause problems for several years.