Dog - Necrosis of the Femoral Head

This condition is also called Legg Calve Perthes disease, von Perthes disease or sometimes Terrier Hip disease.

What is the condition?

The hip joint is basically a ball and socket joint.  During growth it is essential that both the socket (in the hip), and the ball at the end of the femur (thigh bone) grow at the same rate.  For various reasons in certain breeds, particularly terriers, this does not happen.  The blood supply to the growing femoral head (ball part) becomes depleted and the femoral head dies.  The body then attempts to repair the joint resulting in a deformed femoral head, which in turn stimulates arthritis so that there is progressive unilateral (one sided), or in some cases bilateral (both sides), hind leg lameness, pain and restricted joint movement in a dog sometimes only five to six months old.

What is the cause?

We know that it is a hereditary (genetic) condition in small breed juvenile dogs, particularly terriers.  It is associated with an autosomal recessive gene.

How is it diagnosed?

Usually slowly increasing lameness and not wanting to bear weight are the main clinical signs.  Usually one hind leg is affected before the other but occasionally small dogs are presented with the condition affecting both sides simultaneously.  On clinical examination there is usually restricted joint movement, lack of muscle and apparent limb shortening.  Owners often speak of a change in temperament.  A sweet tempered Toy Poodle becoming increasingly snappy is an example.  Radiographys (x-rays) confirm the diagnosis.

What is the treatment?

Excision arthroplasty is the treatment of choice.  The whole of the articular surface (ball) of the femur is surgically removed.  Since the condition affects small, young dogs, especially terrier types, it has been found unnecessary to replace the hip joint which is necessary in larger, heavier dogs, e.g. those suffering from hip dysplasia.  Post operatively dogs suffering from Perthes disease are usually walking well about 4-6 weeks post operatively.

What happens to the joint if part of the hip is removed?

Healing involves the production of fibrous tissue and in a very short time in a young dog a 'false joint' is created.  Within months, in the majority of cases, it will be hard to tell that the femoral head has been removed.

Do complications occur?

Occasionally return of function does not occur as anticipated or the dog starts to use the limb and then once more shows signs of increasing lameness.  This however is relatively uncommon but sometimes involves further surgery.

Will I be able to breed from my dog?

In view of the hereditary implications please discuss this with us since in the majority of cases it is preferable that you do not breed from an affected animal.

Do any other complications occur?

In a significant proportion of cases of von Perthes disease a slipping knee cap (luxation of the patella) can occur as well.  This can result in further lameness following the hip surgery.  This is a relatively uncommon complication but usually requires further surgery to stabilise the patella.

If you have any concerns please feel free to contact us.