BACKGROUND:   Hip replacement, or arthroplasty, is a surgical procedure in which the disease parts of the hip joint are removed and replaced with artificial parts, called prosthesis.  The goal of hip replacement surgery is to increase mobility, relieve pain, and improve the function of the hip joint.  People who have hip joint damage that interferes with their daily activities and are not benefitting from treatment are candidates for hip replacement surgery.  The most common cause of hip joint damage is Osteoarthritis, but other conditions like rheumatoid arthritis, osteonecrosis (the death of bone caused by insufficient blood supply), injuries, bone tumors, and fractures can also lead to the breakdown of the hip joint.  Doctors used to reserve hip replacement surgery for people over 60 years old.  They thought that older people are less active and put less stress on the artificial hip than younger people.  In recent years, however, doctors have found that hip replacement surgery can be successful in younger people because technology has improved the artificial parts.  Today a person’s overall health and activity level is more important than age in predicting a hip replacement’s success. (Source: www.niams.hih.gov)

 

SURGERY AND OTHER TREATMENT OPTIONS:  Before a total hip replacement can be considered, the doctor may want to try other methods of treatment, like exercise, walking aids, and medication.  Exercising can strengthen the muscles around the hip joint.  Walking aids, such as canes and walkers, may hinder some of the stress from damaged hips.  Doctors recommend the analgesic medication acetaminophen for hip pain without inflammation.  If there is inflammation, treatment consists of non-steroidal anti-inflammatory drugs, or NSAIDS (aspirin or ibuprofen).  Some cases require stronger medication, like tramadol or codeine.  Topical analgesic products can also provide additional relief.  Sometimes corticosteroids are injected into the hip joint to alleviate pain.  If exercise and medicine do not alleviate pain, then doctors will recommend a less complex corrective surgery, osteotomy.  This procedure involves cutting and realigning bones to shift weight from the damaged bone to a healthy one.  (Source: www.niams.nih.gov)

 

NEW TECHNOLOGY:  During a traditional hip replacement, which lasts one to two hours, the surgeon makes a six to eight inch incision over the side of the hip through the muscles and removes the diseased bone tissue and cartilage from the hip joint.  The surgeon then replaces the head of the femur and acetabulum with new artificial parts. (Source: www.niams.nih.gov)  However, new discoveries are allowing doctors to use anterior (front), posterior (back), and lateral (side) hip replacement techniques.  The direct anterior hip replacement technique utilizes a muscle interval in front of the hip joint where muscles and tendons are not cut for joint exposure.  It has some added benefits: total hip joint replacement and reconstruction, it allows the surgeon to make a smaller surgical incision (leading to less blood loss, scarring, and tissue damage), and muscles surrounding the hip joint are separated at intervals that naturally occur within the tissue (muscles are not cut so patients do not have to heal from surgical trauma as well).  Patients who have had direct anterior hip replacement surgery report that the post-operative pain is remarkably less than traditional approaches.  Also the recovery time is faster.  Most patients get to leave the hospital after the second day and are walking with aids by the second week.  (Source: www.stevenbarnettmd.com)

 

Stefan Kreuzer, MD, Associate Professor at the University of Texas Health Science Center at Houston, talks about a new procedure for hip replacement. 

What sets this hip surgery apart from a traditional hip replacement? 

Dr. Kreuzer: I believe the anterior approach is a less invasive approach. Fewer muscles are cut during the surgery and it significantly facilitates the early postoperative recovery.

How did this approach come to light?

Dr. Kreuzer: As this is a recent significant advancement, it has been done for many years. In Paris, they have been doing this for over 50 years, but because of the challenges with leg positioning and with the requirement of a special table it was not as cost effective. 

What has changed that has made it more cost effective?

Dr. Kreuzer: I think recently that with the advent of internet, the patient being more educated, and hospitals trying to improve patient care they are more likely to fund these additional expenses to provide the care for their patients.

You talked a little bit about the table being key to the operation, is that correct? 

Dr. Kreuzer: You can do the operation without a table, but it is more challenging especially for surgeon who do not do a large number of hip replacement per year. The exposure of the femur is really key to success and with a table, or table attachment, it facilitates that portion a great deal.

Can you explain a little further, the differences in going from behind to the side to the front with the muscles?

Dr. Kreuzer: Most of the muscles of daily activities that are important for getting out of a chair, getting off the commode, or getting in and out of a car are in the back of the hip joint. When you do a posterior approach, you have to cut these muscles; so all these functions are more difficult to do in the recovery phase. Also, the muscles in the back of the hip joint are the dynamic stabilizer of the hip joint and they facilitate the stability of the hip. The literature certainly shows that with a posterior approach, there is a much higher rate of dislocation.

This cuts down on dislocation risk as well?

Dr. Kreuzer: A great deal. When you look at the comparative literature and the published literature, dislocation rate is anywhere from 1% to 5% using posterior approach. With the anterior approach, it is 0.28% at in our series of 720 consecutive total hip replacements. 

Is going through the posterior still the more common way or are you seeing it switch to the front?  

Dr. Kreuzer: It is more common still, but the anterior approach is really becoming more and more popular amongst surgeons. In fact, every year at our National Society meeting of the American Academy of Hip and Knee Surgeons, they do a show of hands on who does anterior approach. Every year, it moves up. This last year, 19% of the surgeons in the audience were performing anterior approach.

Would you like to see that trend continue to where it becomes more the standard?

Dr. Kreuzer: Yes. I think it will continue to increase slowly and then once it gets accepted in the academic institution, where the residents and the fellows get trained, then I think it will really take off even further.

What is the future of it? You talked a little bit about, maybe adding robotics to the mix. Is that right? 

Dr. Kreuzer: Yes. I think in hip replacement the anterior approach has been a significant advancement, but one of the keys to success as well for long term survival of the implant is accuracy of implantation. So, what we have recently done is join up with robotics company to help improve the accuracy of implantation further and to improve more accurate reconstruction of leg length.