What is a surgical approach?
The anatomic pathway used to reach the bones of the hip joint is also referred to as the surgical approach. Each surgical approach is a different technique to gain access to the joint itself, and expose the anatomy for a hip replacement or hip resurfacing.
The most common hip joint surgical approach used by surgeons in the United States is called the posterior (from the rear) approach. Patients who have had a posterior approach typically have a curved scar on the outside of the thigh with a top part of the scar curving into the buttock. This approach is very popular, easy to learn, predictable and cuts through a limited amount of muscle and tendon, resulting in good recovery.
Even in the hands of very good surgeons, the posterior approach is associated with a small risk of the hip popping out after surgery. Newer techniques and implants have reduced this risk somewhat, but a small possibility of hip dislocation remains associated with the posterior approach.
Another common surgical approach to hip replacement is the lateral (from the side) approach. The lateral approach also involves a scar on the side of the thigh, but instead of being curved, the scar is usually a straight line. The advantage of this approach over the posterior approach described above is a lower risk of dislocation.
The lateral approach nearly eliminates the risk of dislocation, but the approach involves cutting through more muscle tissue on the way to the hip joint. As a result, patients usually have a slight limp after surgery, which generally disappears 6 to 12 months following surgery.
The approach we use is called the anterior (from the front) approach. This method is still new in the U.S., with more surgeons using it every year. Very few surgeons in the U.S. use this approach routinely for all hip replacements. This is a true muscle-sparing approach with a very quick recovery.
Why do you prefer the anterior approach?
One advantage of the anterior approach relates to easier and safer patient positioning for surgery. The patient is positioned on the back, which is a more natural position than placing the patient on the side, which is required in the posterior and lateral approaches.
Another advantage is that leg length checks are easier when the patient is on his or her back. Both legs can be easily assessed relative to each other.
Finally, the anterior approach does not cut through any muscle. The muscles are separated along their natural planes, and the entire joint can be replaced through a much shorter incision, with true sparing of muscle.
Muscle-sparing is beneficial in another way. The risk of dislocation (the hip ball popping out of the socket unexpectedly) is nearly zero with the anterior approach. With other methods of hip replacement, patients must follow certain precautions for a lifetime. For example, patients are usually advised to not bend too far, tie shoes or cross the legs for fear of the hip popping out of socket. These precautions and worries do not apply to hips replaced using our anterior approach.
How did you adopt the anterior approach for hip surgery?
Around 2003, surgeons in Chicago developed a “two-incision” hip surgical approach as the first truly minimally invasive hip replacement. We adopted that technique, published our results in peer-reviewed literature and refined the method to make it safe and predictable in our patients.
The present-day anterior approach is an evolution of that work; instead of two incisions, the anterior approach allows us to perform the entire hip replacement through one short skin incision placed toward the front of the thigh.
Our experience and that of other surgeons in the country shows that patient recovery and function are better with the anterior approach, when compared to conventional techniques. That is why we routinely use this approach for all hip replacement and resurfacing surgeries.
What are the disadvantages to the anterior approach?
This technique is still relatively new and not widely used in the United States, since it involves new learning and is difficult to master. Very few surgeons use it routinely in all patients, given the technical challenges in learning it and getting comfortable with the technique.
Another reason is that with the scar in the front there is the risk of skin numbness over the side and front of the thigh as the result of microscopic skin nerves that are cut in during surgery. These nerves heal over time, and thigh sensation is restored a few months after surgery. The nerves do not affect any muscles; subjective numbness is the only symptom.
In our experience with more than 3,000 patients, thigh numbness has not been a significant issue other than a transient symptom that resolves. It is generally agreed that the temporary numbness is more than balanced out by the substantially improved recovery, reduced pain, absence of a limp, faster return to function and virtual elimination of the risk of hip dislocation.
Which surgical approach do you use in complex total hip replacement?
In very difficult hip reconstructions, such as those in which the hip has been replaced many times previously, or the pelvis has to be repaired with plates and screws before placing a metal socket, or where extensive repair of the femur is needed, the surgical method that spares the muscles while permitting the best exposure is called a trochanteric osteotomy.
A trochanteric osteotomy involves cutting a piece of bone near the top of the femur. This bone is called the trochanter, and is the bump you can feel on the side of the thigh. The major hip muscles involved in walking all attach to the trochanter.
Cutting the trochanter with all the muscles still attached is the oldest of hip approaches. Once the trochanter is cut, it can be moved aside along with the attached muscles, thereby facilitating entry into the hip joint. The resulting view of the hip is excellent for any type of hip replacement, no matter how complicated or difficult.
Metal cables are used to reattach the trochanter to the femur. The trochanter can be attached farther down the femur if tightening of the muscles is desired. This method gives the surgeon the freedom and flexibility to adjust leg lengths and tissue tension, independent of each other.
For first-time hip replacements, and even many repeat hip replacements, a trochanteric osteotomy, despite its above advantages, is rarely needed. We use this method when dictated by complex, difficult and unusual hip replacement cases.
Do you use computer navigation during hip replacement surgery?
Precise alignment of the bones and components is essential to the long-term success of both hip replacement and hip resurfacing. Computer and robotic technology can help in alignment of bones and reduce the possibility of error.
We continue to investigate these technologies as they evolve; however, so far there is no substitute for the skill, judgment, experience, hands and eyes of a high-volume surgeon.
Future technology is aimed at building custom hip components for each patient, thereby ensuring a precise operation and optimal implant placement, with no need for robots or computers.
What is the role of computer guidance in hip replacement?
At present, computer-assisted technology is most effective for low-volume surgeons. It helps such surgeons reduce the likelihood of error in implantation of the hip components. For some surgeons and hospitals, the greatest advantage of this technology is in marketing.
In other words, computer and robotic technology, while sounding fancy, do not add much value to the hands of an experienced, high-volume surgeon.
Do you perform minimally invasive hip replacement I read about?
We have extensive experience in all types of minimally invasive hip surgery described in professional literature. Bear in mind though that all surgery is invasive to the mind, body and psyche. Surgery is a very different experience for the patient than it is for the surgeon, hospital or implant manufacturer. Hip surgery is much easier today when compared to the past, but complications, pain, discomfort and recovery still apply. Each patient’s expectations and physical, emotional, personal and spiritual attributes are different and affect recovery profoundly.
For example, some patients can leave the hospital the same day or the day after hip replacement. But this is not true of all patients.
How long will my scar be?
The scar is about three to five inches long, and located on the front of the thigh. The length of the scar can vary, and depends upon patient body size, the severity of arthritis, the condition of the soft tissues and the deformity of the joint.
While the length of the scar has little to do with how fast you heal, everyone prefers to have the shortest scar. We aim for the smallest possible incision that allows safe and efficient surgery, with accurate implant placement.
Independent of the scar length, hip replacement surgery with our anterior approach avoids muscle damage. By spreading muscles apart, the recovery is much faster and easier.
Are there newer surgical approaches being developed?
Yes, we continue to innovate and progress. One example is the “Super-PATH” technique with which we hope improves recovery by minimizing surgery so much, that same-day discharge may be possible for some patients. These efforts entail painstaking, detailed experimental work in the laboratory, extensive cadaver-surgery training, development of new instruments and collaboration with experienced and gifted colleagues nationwide. Our aim is to ensure we keep advancing, growing, improving and innovating the art and science of our profession for the benefit of our patients in mid-Missouri and those who choose to come here from far away states, as well as Canada and Mexico.