Treating hip dysplasia in dogs

 

Canine hip dysplasia has puzzled researchers for the past 50 years. Although certain aspects of this degenerative, painful condition are now understood (or at least agree upon in theory), much must still be learned about helping afflicted dogs and preventing the increasing incidence of the disease. When a dog has hip dysplasia, the joints develop abnormally. The head of the femur or thigh bone, does not fit properly into the acetabulum or hip socket. These “ball and socket” joints become malformed and unstable, causing inflammation and weakness. Depending on the severity of the problem, this can lead to painful and sometimes crippling arthritis.

Hip dysplasia is considered a hereditary condition. The problem primarily affects large dogs. Even when a dog carries genetic traits that will cause it to develop hip dysplasia later in life, it is born with seemingly normal hips. Veterinarian’s are usually unable to diagnose the condition until a dog is 6-10 months old when the dysplasia has developed and the dog is in pain. When a puppy is 5-7 weeks old, however, a veterinarian experienced in the Bardens Palpation technique can make a subjective determination of a tendency toward hip dysplasia.

Early treatment with acupuncture may help alleviate or retard the development of the disease.

Hip dysplasia can result in a painful dislocation (subluxation) of the hip joint or an irregularly formed ball and / or socket. Eventually the dog develops degenerative joint disease, or arthritis, and a chronically painful hip. It is important to note that you may not be aware of your dogs discomfort. The problem has been present since the dog was 2-4 months old, and your pet has learned to live with the pain. Dogs with dysplasia usually do not cry out in pain. They either limp on the sore leg, or are less active than usual. Often, if both hips are painful, a dog will hop like a rabbit while running or going up stairs or stand up slowly, especially in the morning. Once the discomfort subsides after surgery, the dogs personality and activity level improve dramatically. I am often told by pet owners that their dogs play and act like puppies again.

Older dogs with mild cases of hip dysplasia can be treated with pain reducing medication. However, younger dogs with hip dysplasia have a much greater risk of developing debilitating arthritis, because arthritis always worsens with time.

Four surgical procedures are available to treat hip dysplasia: Pectineus Tenotomy, Femoral Head Excision, Triple Osteotomy of the Pelvis  (TPO),  and Total Hip Replacement. Pectineus Tenotomy was popular in the early 1970’s. The procedure involves cutting a section of the pectineus tendon and / or muscle. We do not know exactly how this process relieves pain, although it does seem to , in some cases. It does not however, affect the amount of arthritis that will form over the years. A disadvantage is that the relief it provides may be only temporary. Although it is still performed by some veterinarians, it is generally regarded as an obsolete procedure.

In Femoral Head Excisions, the ball portion of the hip is removed. Because arthritis develops from the ball rubbing abnormally in the socket, removing 1/2 the hip joint, and thus the bone to bone contact, relieves the pain. Once the ball is removed, a piece of muscle or joint tissue is placed between the thigh bone ( femora) and the socket. This causes scar tissue to form which in turn supports the leg.

I recommend Femoral Head Excision for any dyplastic dog weighing 45 pounds or less. A dog in this weight range will regain near normal mobility once it’s hip has healed and scar tissue had formed. Larger dogs do not generally respond as well to the surgery; the scar tissue simply cannot support the heavier weight. Although the pain of dysplasia subsides, a heavier dog has less stamina and sometimes carries the affected leg in an awkward fashion. The recovery period for this surgery can be very long, 4-6 months, and uncomfortable. On the positive side, no exercise restrictions are necessary. In fact, the more exercise the patient gets, the quicker the recovery.

If Femoral Excision is called for, I recommend surgery on both hips at the same time. This forces the dog to use both legs immediately. Operating on only one leg at a time necessitates two hospital stays, two surgery’s under general anesthesia, and additional expense to the owner. This approach also permits the dog to walk around on three legs and delay healing.

Triple Osteotomy of the Pelvis, in use for approximately 10 years, is the most common “preventative” surgery for treating hip dysplasia. I use the word “preventative” advisedly because the procedure does not prevent dysplasia but can prevent arthritis and therefore the pain caused by hip dysplasia. Candidates for Triple Osteotomy of the Pelvis must be at least 7 months old and have signs of partial dislocation of the hip. It is essential that the femoral head and the acetabulum are normal in shape and that there is no arthritis present. The abnormal finding on an X-ray must be only the painful dislocation. If the joint is allowed to remain as it is, arthritis will most likely form within 6-8 weeks. It is therefore important to have the surgery performed as soon as possible once a diagnosis is made in order to prevent arthritis.
The word Osteotomy means to cut bone. The purpose of the surgery is to set the bone into the socket. This is done by cutting the bone in three places and rotating the acetabulum so that the femoral head rests securely within it. Once the bone is cut, it is held in place with a stainless steel plate and screws or a combination of screws and wire. It is not necessary to remove the plates, screws, or wires.

The most important aspect of this surgery is determining the presence of hip dysplasia before arthritis occurs. In breeds that have a high incidence of hip dysplasia, X-rays should be taken at 6 months, 10 months, and 18 months of age. While the dog is sedated, the veterinarian should feel the joints to determine if there is any dislocation as the X-ray could be taken while the hip is not dislocated and therefore yield inaccurate information. Unlike Femoral Head Excision surgery, a Triple Osteotomy can be performed on only one hip at a time. Of the four hip surgeries discussed here, this one is the longest and most difficult. Additionally, we do not want the patient to start walking on it for a while because only the screws are holding the pelvis together. The opposite leg can be scheduled for surgery 6 weeks after the first one. The recovery period for Triple Osteotomy is 6-9 weeks. During that time exercise restrictions must be enforced. The dog is not allowed to use stairs, walk on slippery floors, or go outside unless on a leash. Two to three weeks after surgery, the dog can be walked for exercise. In any practice, there is a 98% success rate for this surgery. Success means that I am satisfied and the owner is satisfied with the dog’s response to the surgery.

Total Hip Replacement involves replacing the ball with stainless steel and the socket with high density plastic. This procedure has been commonplace in the field of human orthopedics for many years. It has also been available at specialized veterinary hospitals for some time, however, it was not until 1976 that the procedure we know and use today was developed. A specially designed artificial hip is made for dogs.

Candidates for Total Hip Replacement typically have arthritis in the hips which caused mobility. Once skeletal maturity occurs, surgery can be performed at any age. I have performed this procedure on dogs as young as 13 months and as old as 14 years. Another indication for Total Hip Replacement is a poorly healed fracture of either the ball or the socket.

Dogs in need of Total Hip Replacement must be examined by the veterinary surgeon to rule out any other possible cause of lameness. Often dogs are referred to me for Total Hip Replacement unnecessarily when a knee (stifle) ligament is torn or when arthritic changes in the spine are causing the pain. It is important that we treat the patient and not the X-ray. Just because a dog has arthritis in the hip does not mean that this is responsible for all of its lameness. Additionally, candidates for Total Hip Replacement must be in good health. Any underlying illness or skin infection must be treated before surgery.

In this procedure, the femoral head is cut off at a carefully determined angle, then all tissue is removed from the marrow cavity of the thigh bone. A trial prosthesis is inserted to ensure a good fit. Next, the cartilage and some underlying bone are removed from the socket and holes are made in the bone for cement that will hold the plastic socket. The plastic socket is then cemented in place. The marrow cavity of the thigh bone is also filled with cement, and the prosthesis inserted. Once the cement hardens (in 3-5 minutes) the ball is locked into the socket and the surgical site is closed. An X-ray is taken after surgery. The patient is discharged 2 days after surgery, and the owner’s are instructed to follow the same restrictions mentioned for the Triple Osteotomy of the Pelvis. Approximately 60% of my patients walk out of the hospital better than they walked in. 6 weeks after surgery a dog is allowed full mobility.

The success rate of this surgery is 95% or better. Almost every pet owner reports that after 6 weeks the pet “feels better than it has ever felt”, “hasn’t felt this good in years”, or ” It’s whole personality has changed- it is a happy dog again”. Once healing is complete, the patient can return to normal activities, running, jumping, and playing ball.

We are also recommending several nutriceutical to the diet-these include MSM, glucosamines,and omega 3 fatty acids as soon as the disease is diagnosed.  These products may help reduce the progression of degenerative joint disease. We are also recommending the use of non-steroidals such as carprofen or Ectogesic for pain control when needed.  Again, acupuncture is a very usesful adjunct in therapy.It can be used as  an initial threapy if surgery is not an option or if the TPO or excision arthroplasty is performed to aid in your pet’s long term comfort.

 

Thanks to -George B. Siemering, D.V.M., Surgical & Orthopedic Service
and To Ron Fallon D.V.M.-Ambulatory Surgical Services 

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