What is total hip replacement?
Total hip replacement, also known as total hip arthroplasty, is a surgical reconstruction of the hip joint using prosthetic parts made of special metals, plastic, and/or ceramics. Total hip replacement surgery is commonly performed in order to repair a hip joint that is suffering from damaged cartilage and/or bone, usually as a result of hip arthritis.
Why is total hip replacement surgery performed?
Total hip replacement surgery is generally performed when there is a substantial amount of damage to the cartilage or bone in the hip joint, and when a patient is suffering from a significant amount of pain. The surgery eliminates the pain associated with these conditions and restores function and mobility to the hip joint. In addition to hip arthritis, total hip replacement may be performed for avascular necrosis (bone death of the femoral head, or ball, of the joint) and other congenital and acquired hip disorders. Occasionally, total hip replacement is the right treatment for hip impingement, when there is severe damage to the cartilage of the hip.
How do I decide when I need a hip replacement?
Choosing to have a hip replacement surgery is a personal decision that is made together with Dr. McLawhorn. Your preference for surgery, your lifestyle demands, and your expectations for outcomes after surgery aid the decision-making process and will guide your choice between nonsurgical care and hip surgery.
In general, when hip pain begins to interfere with your daily life, prevents you from participating in your recreational activities, wakes you from sleep, and/or requires prescription pain medication, hip replacement surgery is a consideration.
What are the goals for total hip replacement surgery?
First and foremost, the purpose of total hip replacement surgery is to improve pain. Other general goals are:
- Improve hip function
- Provide a stable hip that does not dislocate
- Prevent excessive wear of the implanted components
- Avoid complications
Ideally, patients can return to work and the activities they love to perform without worrying about their hip replacement. After complete recovery from surgery, some patients may even forget that they had a hip replacement.
What does total hip replacement surgery involve?
A total hip replacement procedure will be customized depending on the individual needs of each patient and the specific steps involved in the surgery may vary from person to person. However, in most cases, you can expect the following:
- Regional anesthesia is provided with either a spinal or epidural to numb your body from the waist down; sedation through an IV will allow you to sleep throughout the surgery
- Antibiotics are given prior to surgery to prevent infection
- The hip joint is accessed either from the front (anterior) or back (posterior) aspect of the joint
- The damaged femoral head is carefully removed
- Damaged cartilage on the surface of the acetabulum is removed, and the socket is reshaped into a perfect hemisphere
- A metal socket with a plastic or ceramic liner is then placed within the reshaped acetabulum
- A metal stem is placed down the hollowed center of the femur, and a metal or ceramic ball is placed on top of the stem
- The new ball moves inside of the socket liner, providing very low-friction motion
- The soft tissues are closed over the hip joint
What materials are total hip replacements made of?
For almost all patients, the materials chosen for hip implants are biologically inert, meaning your tissues and bone will not “reject” the materials. Dr. McLawhorn takes a personalized approach to selecting implants for each patient, taking into account their expectations, preferences, and bone size, shape and quality. There’s not a “one size fits all” solution. Therefore, the exact implants and their materials may vary from patient to patient. In general, the implants Dr. McLawhorn selects are made of the following materials:
- Acetabulum or “cup” – titanium or cobalt chrome
- Cup liner – highly cross-linked polyethylene (plastic) or ceramic
- Femoral Head or “ball” – cobalt chrome, ceramic, or ceramicised metal
- Femoral stem – titanium or cobalt chrome
- Fixation to bone – uncemented or cemented (polymethyl methacrylate [PMMA])
The acetabular component is almost always fixed to bone without cement. Cemented femoral stems have an excellent track record, and they are useful for patients with very poor bone quality (for example, severe osteoporosis). For uncemented cups and stems, the surfaces of the implants have a coating that permit your bone to grow onto and/or into the implant, unitizing the implant to your body and allowing the bone and implants to share the load of your body weight.
The ceramics used today are very durable, and it is extremely rare for a ceramic femoral head to fracture or crack. Ceramic acetabular liners are used very infrequently, since the wear properties of highly cross-linked polyethylene are superb. Ceramic liners may squeak or occasionally fracture. Therefore, in Dr. McLawhorn’s practice they are reserved for very young patients, who have a preference for ceramic over plastic and understand the risks associated with this option.
How long will a total hip replacement last?
Current data suggests that the lifelong risk of revision or re-do surgery after contemporary total hip replacement is less than 5%. With continued improvements in joint implant technology and surgical techniques, these numbers may improve.
Which surgical approach does Dr. McLawhorn use?
The topic of surgical approaches to the hip has become popular in the news media, and it can be a confusing topic for patients.
There are many approaches to the hip joint — from the front (anterior), from the side (lateral or anterolateral), and from the back (posterior or posterolateral). In reality, there are no “new” surgical approaches to the hip. All of them have been used for well over half a century, although small modifications in surgical techniques have optimized some approaches for hip replacement surgery.
Dr. McLawhorn believes that most patients are candidates for anterior approach surgery. Many patients are pleasantly surprised when Dr. McLawhorn recommends anterior approach THR for them, because they've been told they are not candidates for this approach by other surgeons. An important exception for Dr. McLawhorn is excessive soft tissue (pannus) overlying the area where the surgical incision will be made, as this is a risk for surgical site infection. More rarely, the complexity of the joint replacement may dictate a different surgical approach.
The choice of surgical approach is based upon patient preference, expectations, anatomy, bone quality, and complexity of the hip replacement procedure. Regardless of the surgical approach used, the long-term goals of total hip replacement are the same: eliminate pain, improve function, provide a stable hip, prevent excessive implant wear, and minimize the likelihood of complications.
What is direct anterior approach hip replacement surgery?
The direct anterior approach has been used for hip replacements since the 1950’s, but it didn’t gain popularity in the United States until the early 2000’s. Direct anterior hip replacement surgery is less invasive, causes less muscle damage, and affords quicker recovery than other approaches to the hip. These popular perceptions about the approach have made it a more frequently utilized approach for total hip replacement.
The approach is unique because it accesses the hip joint by utilizing a natural space or “plane” between muscles around the hip, rather than going through muscle or cutting muscle. Therefore, less muscle damage occurs with this approach and it is considered soft tissue-sparing surgery. This leads to less pain and less likelihood for hip dislocation after the surgery.
During the surgery, the patient is placed on his or her back (supine). A skin incision is made over the belly of a muscle, the tensor fascia lata muscle, in front of the hip. The length of the incision is proportional to the depth of the fatty tissue and muscle overlying the hip. It must be long enough to permit full access to the top of the thigh bone and to the socket, so that the prosthetic components can be placed precisely and accurately. Typically an incision that is 4 to 6 inches long is adequate. The muscles in front of the hip are retracted to the sides of the incision, and the anterior (front) of the hip capsule is exposed and incised to access the hip joint. The capsule is repaired at the end of surgery.
After surgery, patients do not have to follow “hip precautions”. While there are hip positions that increase the risk of hip dislocation after a direct anterior approach in the immediate weeks following surgery, they are not common positions during most patients’ everyday activities.
Understanding the Anterior Approach
Using an anterior approach for hip replacement allows Dr. McLawhorn to make incisions at the front of the hip as opposed to cutting through the muscles and tendons. Using this technique also reduces the risk of nerve and muscle injury during surgery.
Advantages of Anterior Approach For Hip Replacement
In addition to reducing muscle and nerve injury, using an anterior approach also offers patients:
- Shorter recovery period: One of the main advantages of using an anterior approach to hip replacement is a shorter recovery period. Since the muscles and nerves are spared during surgery, recovery time is reduced. Patients may also experience less postoperative pain as well.
- Improved stability: Using an anterior approach also provides a visual field for more accurate placement of the hip prosthetic. In turn, this can improve hip stability and even possibly lower the risk of hip dislocation.
- Fewer postoperative restrictions: With fewer incisions and preservation of muscles and tendons, patients may also have fewer postoperative restrictions. Patients may have a better range of motion in their hip and also be able to bear weight sooner when compared to patients who underwent hip replacement via a posterior approach.
What is posterior hip replacement surgery?
Popular media has labeled posterior hip replacement surgery as “traditional” hip replacement surgery. Historically, posterior approach was the dominant approach in the US for hip replacement because of its ease and reproducibility.
During the posterior approach, the patient is placed on his or her side, with the surgical hip facing up towards the ceiling. An incision is made over the buttock, just behind the top of the thighbone. The length of the incision is proportional to the depth of the fatty tissue and muscle overlying the hip. It must be long enough to permit full access to the top of the thighbone and to the socket, so that the prosthetic components can be placed precisely and accurately. Typically an incision that is 4 to 6 inches long is adequate.
Part of the large gluteus maximus muscle is split. There are small tendons and muscles that attached to the back of the hip joint which are released during the hip exposure, and they are repaired at the end of surgery. The posterior hip capsule must be opened to access the hip joint and perform the replacement, but it is also repaired later in the surgery.
In the first 4 to 6 weeks after posterior approach hip surgery, you may be asked to follow “hip precautions”, which entails not performing deep hip flexion, crossing the operated leg across your body (adduction), or internally rotating the hip (generally, positioning the leg so that you see its outer, or lateral, aspect). Combining these motions is the most dangerous in the first 12 weeks after surgery, and can cause a hip dislocation. Following the prescribed precautions allow the repaired soft tissues to heal and will give you a stable hip that is unlikely to dislocate in the future. Dr. McLawhorn has shown that the repair of the capsule and tendons is durable for years after surgery.
While the posterior approach historically had a high dislocation rate compared to other approaches, the soft tissue repair, precise component placement with robotics, and modern implant designs do lower the dislocation risk.
How does the anterior approach compare to the posterior approach?
The primary differences between the anterior approach and posterior approach are (1) the risk of dislocation (lower risk for anterior approach), and (2) usually temporary numbness along the thigh after anterior approach.
|Functional recovery?||No precautions, slightly faster||Precautions, slightly slower|
|Dislocation risk?||Significantly lower||Higher|
|Risk of complication during surgery?||Low, no significant differences||Low, no significant differences|
|Level of postoperative pain?||Lower||Higher|
|Likelihood of major nerve injury?||No difference, very low||No difference, very low|
|Likelihood of minor nerve injury or dysfunction?||Higher, usually affecting the “lateral femoral cutaneous nerve”, and resolves in the majority of instances||Very low|
|Suitability for all patients?||May be less suitable for obese patients or patients with very complex hip anatomy||Suitable for all patients|
|Special table required?||Not required, but often used||Not required, but often used|
|Difference in long-term outcome?||No, other than risk of dislocation (lower)||No, other than risk of dislocation (higher)|
|Use of X-ray during surgery?||Frequently; Easy to use||Almost never; Less easy to use|
|Able to use advanced technology, like computer-assisted or robot-assisted surgery?||Yes||Yes|
Considerations of Surgical Approach
Both surgical approaches provide patients with a variety of benefits, however, it is equally important to understand that not every patient may be a suitable candidate for an anterior or posterior approach.
One of the most significant factors in successfully using an anterior approach is the surgeon’s level of expertise. Surgeons who specialize in anterior approach hip replacements, like Dr. McLawhorn, understand the complexity of a patient’s anatomy.
The patient’s anatomy is equally important. Some patients may not have the right bone structure to use an anterior approach. In those cases, a posterior approach may be the better alternative. Dr. McLawhorn will discuss all of your surgical options in consultation, making sure you understand the pros and cons of each surgical approach.
What can I expect after total hip replacement?
Immediately after surgery, you will be able to walk on your hip replacement. A walker, crutches or cane may be used for several weeks, if needed. Dr. McLawhorn recommends following posterior hip precautions (no hip flexion greater than 90-degrees, no crossing of the operated leg over the body, and no internal rotation) for 6 weeks if you have posterior approach surgery, and following these general guidelines during that time:
- Sit in a high cair or use two pillows on a standard chair
- Use a chair with arm rests
- Keep your knees apart when getting up from a seated position
- Use a raised toilet seat
- Use a pillow between your legs when sleeping at night
He advises anterior hip precautions (no excessive hip extension and no excessive hip external rotation) for 6 weeks after anterior approach surgery. Depending on the demands of your job, you may return to work within 2 weeks of surgery. Return to full normal activity, including heavy labor and sports can occur at 6 months after surgery.
Dr. McLawhorn recommends routine follow-up of all his hip replacement patients. In general, patients will be evaluated at 6 weeks, 12 weeks, 1 year, 2 years, 5 years, and then every 5 years after surgery. A clinical examination and X-rays will be performed at each of these visits.
If you are suffering from debilitating hip pain or hip arthritis and exploring total hip replacement as a treatment option, it is important to seek advice from an orthopedic hip specialist to accurately diagnose and treat your condition. If you've been told you're not a candidate for anterior approach THR, you may want another opinion about your treatment.
Dr. Alexander McLawhorn is a hip specialist at Hospital for Special Surgery serving patients in New York and Stamford, Connecticut. To learn more, call 203-705-2113 (CT) / 212-606-1065 (NYC) today or schedule an appointment by using the form on this page.