Legg Perthes disease

Legg Perthes disease is a medical condition that affects the hip joints of dogs. Dogs have a ball and socket joint in the hip, with the ball located above the thigh bone (femur) and the socket in the pelvis. Legg Perthes disease occurs when the ball (called the femoral head) starts to disintegrate. The gradual disintegration of the femoral head causes pain in their hip, leading to arthritis. 

The exact cause of the disease is not yet known but dogs affected with Legg Perthes disease tend to experience a lack of blood flow to their hip. Disrupted blood flow causes clots within blood vessels and makes their bones weak. In some cases the disease is caused by an injury.

Some studies suggest a genetic reason for the disease, especially in smaller dog breeds but this can’t be confirmed. The disease is common in small dog breeds like Terriers, Pomeranians, Chihuahuas, Poodles and Bichon Frise.

Symptoms of Legg Perthes Disease

The disease is commonly diagnosed in younger dogs between 5 to 8 months of age. But puppies of 2 months of age and even 18 months of age can have the disease. 

Common signs of the disease include:

  • Limping on the affected leg
  • Stiffness near the limb
  • Loss of muscle mass in the affected limb
  • Dogs chewing skin on their hip
  • Extreme pain when the affected leg is moved 
  • Aggressiveness because of pain

Usually the disease onsets with lameness and becomes worse in the following weeks. With the progression of the disease, pain and stiffness in the dog’s limb become more evident. Affected dogs may eventually stop using the leg. This may lead to loss of muscle mass because the dogs are not using their legs.

How is Legg Perthes Disease Diagnosed?

Legg Perthes disease is diagnosed by examining their medical history and clinical signs. The disease starts with lameness of the affected limb and progresses to the dog becoming unable to carry body weight on the limb.

If you think your dog has the disease, share all the details including frequency and duration of symptoms with the vet. Your vet will conduct a physical examination to find out if your dog has Legg Perthes. 

They will conduct multiple x-rays (radiographs) of the affected hip, over a period of time. Changes in the radiographic appearance of the hip joint will help them confirm the diagnosis of the disease.


Mild conditions of Legg Perthes disease are usually managed with medication. Pain medication (including anti-inflammatory drugs) is given to dogs to reduce their pain. While the medicine reduces their pain it does not stop the disease from progressing. If the dog’s condition doesn’t deteriorate, they may be able to live comfortably. If not then surgical intervention will be needed.

In severe cases FHO (Femoral Head and Neck Osteotomy), a surgery to remove the disintegrated femoral head and neck is carried out. Post surgery the body is allowed to heal with scar tissue. This is only a rescue treatment and should be performed on dogs who don’t respond to medication. 

Total Hip Replacement (THR) is another surgery that is performed to treat Legg Perthes disease. In this surgery a functional hip joint is implanted in the hip joint after removing the disintegrated part. While THR seems more practical than FHO, both methods have shown similar results.   

Post surgery the vet will give pain medication and physical therapy to help the dog recover. Regular exercise and care are important to expedite recovery.

Related Questions

Why is the Disease Called Legg Perthes Disease?

Legg Perthes Disease is also called Legg-Calve-Perthes Disease, Femoral Head Necrosis or Aseptic Necrosis or Avascular Necrosis. The disease is named after 3 surgeons who first discovered the condition in children in the early 1900s.

How can I Prevent My Dog From Getting Legg Perthes Disease?

While Legg Perthes can occur in any dog, preventing injuries and accidents can keep your dog from having the disease. Dogs diagnosed with Legg Perthes should be spayed or neutered, to prevent the disease from getting passed to puppies.

Before breeding responsible breeders usually check the hips of dogs who are likely to have the disease. They submit radiographs to Orthopedic Foundation for Animals (OFA) where the dogs are diagnosed for Legg Perthes disease. 

If you plan to get a small dog breed, make sure to ask the breeder if the dog’s parents have been checked for Legg Perthes disease.

How Much Does the Treatment Cost?

Treating Legg Perthes can be expensive, especially if it requires surgery. The cost of FHO surgery ranges from $1,000 to $3,000.