Tuesday, February 9, 2010

Femoral Head and Neck Excision

Article Written by Dr. Daniel A. Degner, Board-certified Veterinary Surgeon (DACVS)

Key Points
  • The femoral head and neck excision will decrease the pain that your pet is experiencing
  • This surgery works best in medium to small dogs, and in cats
  • For optimal recovery, rehabilitation therapy at home and at a rehabilitation center under the direction of a therapist is as important as the surgery is.

Diseases Treated by Femoral Head and Neck Excision

* Hip dysplasia is a very common disease that affects large breed dogs. This disease is caused by the abnormal development of the hip as a puppy grows. Bad genetics are a major contributing factor. Sometimes the dam and sire of the affected puppy are negative for the disease. If this occurs, the parents may have hidden genes for the disease.
* Hip dysplasia results in looseness of the hip joints. Because the joints are loose the head and socket of the hip become deformed. The socket becomes shallow and the head of the femur gets flattened. Arthritis develops in the joint and causes pain. Occasionally the hip joint will be very loose and it will become dislocated with minimal trauma. This usually causes the pet to become suddenly lame. Replacement of the hip back in the joint is generally unsuccessful as the geometry of the joint is so abnormal.
* Typically clinical signs of hip dysplasia can be seen as 4 months of age, however, many dogs are 8 to 12 months of age. Some dogs seem to experience signs of hip dysplasia when they are a couple of years old and others in the geriatric years. The clinical signs of a problem may first start out as exercise intolerance. Bunny hopping, stiffness on rising after a rest, lameness on a limb, and atrophy of the muscles of the hind limbs are typical clinical signs.
* Dislocation of the hip is another condition that requires surgery. If signs of arthritis are present with dislocation the hip or if the dislocation is chronic, then the hip should not be placed back into the socket. Instead total hip replacement or femoral head and neck excision should be performed.
* Severe fractures of the acetabulum or of the head or neck of the femur sometimes cannot be repaired.
* A form of degeneration of the hip joint, called Legg-Calve-Perthes disease occurs in small dogs and is due to damage of blood supply to the femoral head. This disease causes the femoral head to collapse and pain results.
* Below is a radiograph of the pelvis of a dog that has severe left and right hip dysplasia and is a candidate for femoral head and neck excision; the H denotes the hip joint on the left.

Summary of diseases that could benefit from femoral head and neck excision

* Hip dysplasia
* Dislocation of the hip with concurrent arthritis
* Fractures of the hip joint which are not repairable (head of femur or acetabulum)
* Legg-Calve-Perthes disease

Femoral Head and Neck Excision

* The pet will be anesthetized and the entire limb and hip to be operated will be clipped.
* An incision is made over the hip region.
* The hip is exposed and the femoral head and neck is removed.
* The muscle, fat and skin layers are then closed. If deemed necessary, the femoral head is submitted for analysis by a pathologist.
* After the surgery, fibrous tissue forms in the area of the hip joint which prevents bone rubbing on bone. The muscles hold the hip in place. The operated limb will be slightly shorter than prior to surgery, but this should not cause any functional problems.
* In the radiograph below, this dog has had both femoral heads removed. Take note of the femoral head and neck excision site on the right (R) which was recently done; the excision is very clean and prevents the bone from rubbing on the hip socket (called the acetabulum) of the pelvis. Also take note that the left hip has also had the FHO procedure, but this one was operated years ago and new bone has grown on the site of the FHO, but it is not contacting the pelvis and is not causing any clinical problems.

After Care and Convalescence

* After surgery has been completed intensive care is provided.
* Pain control after surgery is maintained with morphine as needed. While at home, oral pain medication may be needed and a prescription of Tylenol #4 will be given to you at the time of discharge of your pet.
* Activity is not limited after surgery. In fact, exercise will help to maintain a good range of motion of the hip joint. The owner should do rehabilitation therapy until the pet is using the limb normally. This involves flexing and extending the hip joint. Physiotherapy will help prevent adhesions from forming, thus maintaining a good range of motion of the hip region. Another form of physiotherapy is swimming if such a facility is available. It is also highly recommended that rehabilitation therapy sessions be scheduled with our therapist.
* Most dogs will start to bear a small amount of weight on the limb within 2 weeks after surgery. Within 4 to 6 weeks your pet should bear a moderate amount of weight on the limb. By 2 to 3 months after surgery recovery is complete.
* Your pet should be examined 2 weeks and 3 months after surgery to ensure that the hip region is healing well.
* Most small pets do well following femoral head and neck excision surgery. Larger dogs can also do well but some weakness on that limb frequently can be seen. This is due to the muscles supporting the region of the hip instead of the actual joint. As a result, heavy exercise can cause the pet to become stiff or lame. Anti-inflammatory medication can be given to give your pet relief if needed. If you pet is a medium to large breed dog, total hip replacement is the preferred technique over femoral head and neck excision.


* As with any surgery, complications may arise. Even though rare, anesthetic death can occur. With the use of modern anesthetic protocols and extensive monitoring devices (blood pressure, EKG, pulse oxymetry, inspiratory and expiratory carbon dioxide levels, and respiration rate), the risk of problems with anesthesia is minimal.
* Infection is also an unusual complication, as strict sterile technique is used during the surgery.
* Poor range of motion of the hip joint can occur. Generally this is due to lack of rehabilitation therapy. If your pet is not using the limb very well after 2 to 3 weeks, anti-inflammatory therapy should be considered.
* Sciatic nerve damage is a potential complication during FHO surgery. During the years of performing this type of surgery we have not witnessed this.
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