Varus Osteotomy

What is Varus Osteotomy?

Varus osteotomy, also known as varus derotation osteotomy (VDRO), is a surgical procedure employed to treat children with hip dislocation or children who are at risk of hip dislocation. A varus deformity is a severe inward turning of the distal section of a joint or bone. Generally, children with weak muscles or spasticity or who are unable to walk or have excessive inward angulation of the feet commonly develop hip dislocation over time.

In a normal hip, the ball-shaped head of the femur (thighbone) is completely held within the cup-shaped socket (acetabulum) of the pelvis. If the ball is out of the socket, it is known as dislocation. Varus osteotomy is a surgery designed to adjust the ball of the femur so that it fits precisely into the hip socket.

Congenital conditions such as developmental dysplasia of the hip (DDH) and developmental disorders such as spastic cerebral palsy are known to cause hip dislocation and instability in children warranting varus osteotomy surgery.

Anatomy of the Hip

The hip joint is a ball-and-socket joint. A part of the pelvis bone known as the acetabulum forms the cup-shaped socket and the upper end of the femur, known as the femoral head, forms the ball. It is surrounded by strong muscles and tough ligaments that prevent the dislocation of the hip. The joint surface is covered by smooth articular cartilage that cushions and enables smooth movement of the joint.

Indications for Varus Osteotomy Surgery

Varus osteotomy is usually indicated if the child’s hip is more than thirty percent out of the socket and is likely to get worse. If the hip becomes half or fully dislocated, it can become extremely painful for your child as she or he grows. If the hip has been in a dislocated state for many years, putting it back into the socket may not be feasible. A child with a dislocated hip may have:

• Leg length discrepancy
• Difficulty with standing or sitting
• Limited range of movement
• Pain or discomfort
• Infections in the skin fold
• Skin breakdown
• Difficulty with getting dressed or diapers changed

Preparation for Varus Osteotomy Surgery

Preoperative preparation for varus osteotomy will involve the following steps:

• A thorough examination of the patient’s limb is performed by the physician that involves measurement of the clinical malformations (angular, rotational, or translational) and limb lengths.
• Physical exam also involves assessment of gait pattern, long bone torsion, ligamentous laxity, and patellar tracking.
• Depending on the patient’s medical history, social history, and age, the patient may need to undergo tests such as blood work and imaging to help detect any abnormalities that could threaten the safety of the procedure.
• You will be asked if the patient has allergies to medications, anesthesia, or latex.
• You should inform your doctor of any medications, vitamins, or supplements that the patient is taking.
• The patient should refrain from medications or supplements such as blood thinners, aspirin, or anti-inflammatory medicines for 1 to 2 weeks prior to surgery.
• The patient should not consume any solids or liquids at least 8 hours prior to surgery.
• A written consent will be obtained from you after the surgical procedure has been explained in detail.

Procedure for Varus Osteotomy Surgery

Varus osteotomy is usually performed under general anesthesia and involves the following steps:

• Your child’s surgeon makes an incision of several inches along the outside of your child’s hip.
• The underlying subcutaneous fat and muscles are retracted to expose the upper end of the femur.
• A small section of the femur is cut under the neck portion. This allows the femoral head to be tilted so that it firmly rests within the socket.
• Once the femoral head is firmly placed in the socket, an assessment is made to determine whether an additional procedure is required to correct the socket angle. Sometimes, the socket may have stretched so much over time that the femoral head may no longer fit comfortably. In this circumstance, the socket will be diligently reshaped to exactly match the femoral head.
• Metal plates and screws are utilized to hold the hip bone in this new position, until it is completely healed.
• These plates and screws may need to be taken out once complete healing is accomplished in a year or two.
• All surrounding tissues and structures are restored to their normal anatomic position.
• Finally, the incision is closed with sutures and sterile dressings are applied.

Postoperative Care and Recovery

In general, postoperative care instructions and recovery will involve the following steps:

• The patient will be transferred to the recovery area to be monitored until the patient is awake from the anesthesia.
• The patient’s nurse will monitor the blood oxygen level and other vital signs as the patient recovers.
• The patient may notice some pain, swelling, and discomfort in the operated area. Pain and anti-inflammatory medications are provided as needed.
• Medications may also be prescribed as needed for symptoms associated with anesthesia, such as vomiting and nausea.
• Antibiotics are prescribed to address the risk of surgery-related infection.
• Keep the surgical site clean and dry. Instructions on surgical site care and bathing will be provided.
• The patient is encouraged to walk with assistance as frequently as possible to prevent the risk of blood clots.
• Eating a healthy diet rich in vitamin D is strongly advised to promote healing and a faster recovery.
• The patient should refrain from strenuous activities and lifting heavy weights for the first couple of months. Gradual increase in activities over a period of time is recommended.
• A physical therapy protocol is usually recommended to help strengthen muscles and optimize joint function.
• Most children typically stay in the hospital for 5 to 7 days depending upon the procedures performed.
• Most patients will be able to resume normal activities within 2 to 3 weeks with certain activity restrictions.
• A periodic follow-up appointment will be scheduled to monitor the progress.

Risks and Complications

Varus osteotomy surgery is a relatively safe procedure; however, as with any surgical procedure, it does carry some risks and complications, including:

• Blood clots
• Infection 
• Bleeding
• Joint stiffness
• Loss of function
• Injury to nerves and blood vessels
• Anesthetic-related complications
• Implant failure
• Revision surgery