Hip Dysplasia

Hip dysplasia is a congenital disease that affects mostly large breed dogs. It causes weakness and lameness to the rear quarters, and eventually leads to painful arthritis.

Cause

Many factors work together to cause this genetic disease. The breeding of dogs that already have hip dysplasia is one of the primary reasons the disease is still present. It is also postulated that excess calcium in the diet of puppy food for large breed dogs adds to the problem. In addition, a dog that has hip dysplasia in one socket is prone to having a problem with the ligaments of the knee in the other leg (anterior cruciate rupture).

Diagnosis

Hip Dysplasia is diagnosed based on a history of weakness or lameness to the rear legs, especially after exercise or when first getting up after resting. Some young dogs will bunny hop when running, and might lie down on their stomachs with their legs stretched behind them. It is possible to palpate joint laxity on some dogs that are anesthetized (we call this the Ortolani sign). Radiography is the definitive way this disease is diagnosed.

These are the x-rays of a dog with a normal pelvis. The diagram below explains why these hips are normal. View both of them at the same time if possible.

On the right side of this normal pelvis we have outlined 2 important anatomical features. The "U" shaped appearance of the neck (outlined in white), and the full rounded appearance of the head (outlined in black), are normal. They indicate a full socket with a tight fit and no signs of secondary changes due to instability of the ball and socket joint.

This dog has moderate changes that indicate it has hip dysplasia on the right side. The socket is not as rounded as it could be, and the head of the femur is slightly flattened. Also, the neck of the femur does not have the U shaped indentation that is normal. You can see this better on the closeup views below.

The arrow points to the thickening in the femoral neck in the abnormal right socket. You can also visualize the slightly flattened appearance of the head of the femur and the fact that it does not fit into the socket as tight as the normal hip marked left.

This is a case of severe hip dysplasia. The arrows point to the thickened femoral neck on each side along with the secondary arthritis occurring on the left side. Notice how flat the sockets are and the lack of rounded appearance of the femoral head. This dog is probably in pain and has a difficult time walking in the rear quarters.

If left untreated the disease continues to progress, eventually causing a crippling lameness and severe pain. Correcting this problem at an early age might have prevented this.

Medical Treatment

Several oral and injectable medications are used to treat mild cases of hip dysplasia. Our doctors will let you know if they apply in your specific case. They can be very effective in eliminating the pain that is associated with this disease, but won't prevent secondary arthritis from eventually forming. Most dogs diagnosed at a young age have a better long term prognosis if surgery is performed.

Surgical Treatment

This area contains graphic pictures of actual surgical procedures performed at the hospital. It may not be suitable for some children (and some adults also!).

Most cases of hip dysplasia, especially in younger dogs, are treated surgically. One of the specialists we consult with will make the determination of which procedure is the most appropriate. Three main types of surgery are performed:

1. Femoral Head Ostectomy (FHO)

In this procedure the head (or ball) of the femur is removed. The remaining part of the femur forms a false joint with the muscles, ligaments, and tendons in the area. Most pets that have this surgery return to almost 100% function.

This are the hips of Mickey, a very active Australian Shepherd. He has hip dysplasia on both sides. FHO surgery will be performed on his right hip.

After the skin incision is made the muscles are separated to give visualization of the femoral head. It is gently rotated and brought up as far as possible.

A special air power drill is used to cut the neck of the femur at just the right angle.

The angle in the cut of the femoral neck is apparent. Also present on the head of this femur is a piece of the round ligament, one of the structures that anchors the head of the femur into the socket.

An opening remains where the head of the femur used to reside. The remaining bone will form a false joint, and return this pet to almost 100% function.

The muscles that were separated and cut are now carefully sutured. These muscles are necessary for normal movement of the false joint that will soon form.

This is what remains after the surgery. Mickey healed rapidly after the surgery and is running around as fast as before, according to his worried mom.

2. Triple Pelvic Osteotomy (TPO)

This surgery is used in large breed dogs no older than 10 months of age. Candidates for this surgery can only have mild hip dysplasia and no signs of secondary arthritis. During the procedure the pelvis is cut and rotated slightly so that the head of the femur has a tighter fit into the socket. Since the pelvis is being cut it needs to be stabilized with bone plates.

This is the final result after a TPO surgery. These two plates are angled to provide the proper pelvic rotation.

3. Total Hip Replacement (THR)

In this procedure the neck and head of the femur are replaced with stainless steel or titanium implants. This is a highly specialized procedure performed only by select veterinarians. It is used in young dogs that have achieved most of their skeletal growth and in adult dogs that weigh at least 40 pounds. It has a high success rate but has to be performed carefully because if post operative complications occur they can be disastrous.

This is the end result of the surgery. These implants now make up the ball and socket joint, and will remain fully functional for many years.

Prevention

This is achieved by neutering pets that have the disease. Dogs can be screened for this problem by taking radiographs of their hips at 2 years of age. If they are certified free of hip dysplasia by the Orthopedic Foundation of America (OFA) then there is much less of a chance they will sire offspring with the problem. It is best to purchase large breed dogs only if their parents are OFA certified to be hip dysplasia free.

Navigation Area