Hip Dislocation

Hip Dislocation
The hip joint is a “ball and socket” type joint attaching the rear leg to the body.  The femur head is held in place by a thick ligament and the fact that the whole joint is enclosed in a fibrous capsule. The local hip muscles also help support the joint.

The Patient
A radiograph is necessary to confirm the diagnosis.  The patient will not be bearing weight on the affected leg and the leg may actually seem shorter than the other three.

Surgical correction is recommended to maintain function of the leg and reduce pain. 

Closed Reduction
Closed reduction means that the bones are put back without surgically opening the joint. If the hip appears to be normal other than the luxation, it is probably worth at least attempting closed reduction; although after 3 days local muscle contraction makes successful reduction very difficult.

To reduce the luxated hip, the patient must be anesthetized to relax the local muscles. The femoral head is manipulated back into place.  Radiographs confirm the reduction and a sling is placed to keep the hip bones together while the joint capsule around them heals.

This may sound simple enough but it is often unsuccessful. Large dogs are difficult to manipulate and the joint tends to promptly reluxate. Do not be surprised if closed reduction proves impossible and surgery is recommended.

The sling, called an “Ehmer” sling, involves flexing up the knee and taping the foot to the thigh. The sling stays on approximately 1 to 2 weeks, while the patient leads a confined lifestyle indoors at home. The bandages must stay clean and dry. After the sling has been on an appropriate time the sling is removed and confinement continues another 2 to 4 weeks.

The Femoral Head Ostectomy
This surgery is commonly referred to as the “FHO” and is best used for smaller dogs (50 lbs or less) and cats.  Here, the femoral head is cut off and removed, allowing the joint to heal as a “false joint” (just a capsule connecting the two bones but no actual bone to bone contact).  If the dog is very active, a false joint will form quickly.  The leg should be used nearly normally after a couple of months. Many veterinarians are well experienced with this surgery and often a specialist is not needed. This surgery is typically substantially less expensive than the other procedures.

Surgery

There are many techniques of surgical treatment that might be employed in keeping the bones where they are supposed to be. All of these techniques require a surgical specialist.  In a perfect situation, the hip is reduced and only a small tear in the joint capsule is present. Sewing the joint capsule back together holds the femoral head where it belongs in the acetabulum.
In a less perfect situation, the joint capsule is too damaged to simply sew back together. In this situation, screws can be placed around the acetabulum and a hole drilled through the neck of the femur. A stiff suture can run around the screws and through the femoral neck holding the femoral head in place.

Another technique uses a pin passing from the femur, out the femoral head and into the bone of the acetabulum like an axle.

Total hip replacement is also available, especially if the dog has hip dysplasia. 

There are numerous methods and the surgeon will choose the most appropriate. Expect a sling as described to be necessary for at least a week and confinement for at least a couple of weeks after that to be necessary.

This procedure is particularly helpful for cats.