Aseptic Femoral Head Necrosis in Dogs

Aseptic femoral head necrosis in dogs can affect any breed, but it typically develops in smaller breeds. This condition can be caused by damage to the hip joint or can develop due to a genetic condition. Either way, most dogs slowly develop symptoms over a period of time with a slow progression of worsening symptoms. If your dog is diagnosed with aseptic femoral head necrosis, there are a few therapies veterinarians can offer to give your dog pain relief, but surgery is the most common fix.

Aseptic femoral head necrosis in dogs can appear with no known cause. If your dog is having trouble walking or experiencing any sort of pain in their hind end, you should take them to a veterinarian for evaluation.

If your dog is suffering from aseptic femoral head necrosis, they may or may not develop some of the symptoms listed below:

• Irritability
• Chewing at the hip or flank
• Pain 
• Medial patella luxation 
• Progressive hind limb lameness, unilateral or bilateral
• Restricted joint movement
• Muscle atrophy of affected limb
• Inability to bear weight on the affected leg
• Crepitus of the hip joint

Types

Aseptic femoral head necrosis in dogs can go by many other names. Different names of the same disease include Legg-Calve-Perthes disease, Calve-Perthes disease, Legg-Perthes disease, avascular necrosis of the femoral head, osteochondritis juvenilis, and coxa plana. It can affect a canine unilaterally or bilaterally, although bilateral necrosis is less common. 

Aseptic femoral head necrosis is a disease of the hip joint that results in a deformity of the ball of the hip joint. The blood supply to the femoral head gets damaged and the bone begins to die off. The cartilage that coats the femoral head becomes cracked and deformed, leading to arthritis or inflammation of the hip joint.

Causes of aseptic femoral head necrosis are not entirely understood. Injury to the area can result in compression of the vessels to the femoral head causing the blood supply to be decreased or possibly cut off entirely leading to bone death. Another cause can be from genetics; it is potentially hereditary so breeding of a dog with femoral head necrosis is not advised. Abnormal sex hormone activity can be another cause of this issue. Scientists are still studying all the affects hormones play on the body in growing pets.

When it comes to diagnosing this condition, there are only a few ways to get reliable results. Ways to diagnose aseptic femoral head necrosis include:

• Pain upon manipulation of the hip joint; mainly when extending and abducting the leg
• Reduced muscle movement
• Crepitus
• Muscle atrophy
• Appearance of limb shortening
• Radiography findings may include irregular density of the femoral head (can appear ‘moth-eaten’), irregular density of the femoral neck, flattening of the femoral head, bone spurs, increased joint space

There are a few different ways to treat aseptic femoral head necrosis. If it is caught and properly diagnosed early on where the femoral head is still shaped normally and seated firmly in the socket, it is possible to treat it with physical therapy and cage rest. However, in most cases, this condition is caught too late for this to be helpful. 

Surgery is most common treatment typically performed in dogs with aseptic femoral head necrosis. The surgical correction is known as femoral head and neck ostectomy, or FHO. This surgery involves the removal of the femoral head and neck. In larger breed dogs, sometimes a total hip replacement is suggested but in smaller breeds a total hip replacement is unnecessary. 

Other types of treatments can be used to manage the pain but will not correct the condition. Photobiomodulation, or laser light therapy, is a form of ‘alternative’ therapy. Laser therapy is a newer therapy to the veterinary field but it is extremely effective. Laser therapy increases circulation to the area, increases anti-inflammatory properties, and increases cell production in the area leading to increased healing time. 

Acupuncture can also be an alternative therapy used to treat the area for pain, increase blood flow to the area, relieve some of the arthritis, as well as increase range of mobility. There are also other holistic practices and therapies you can utilize that are not commonly known but still show amazing improvement in your dog.

Some dogs experience long term limping or discomfort and need continual pain medication. Most dogs recover very well from FHO surgery. When part of the affected hip joint is removed, the body lays down fibrous tissue in a very short amount of time creating a false joint. Of course your dog will need to be rested for a while, but then he should be back to his energetic self in no time.