Dr. Murphy most commonly performs total hip arthroplasty using an exposure called the Superior Hip Approach.  This is a technique that he invented and developed in 2002 and 2003 and which received patents in 2005 and 2006. The aim of the technique is to maximally preserve the soft tissues surrounding the hip joint and to perform the surgery without every dislocating the hip joint or distorting the limb beyond the normal range of motion of the hip. It is the only hip replacement technique that has received two patents.   It is considered a "minimally invasive hip replacement" technique, although all hip replacement surgery is invasive to a greater or lesser extent. This procedure can be performed in more than 99% of the primary hip replacements that Dr. Murphy performs and he has used it for more than 3000 hip replacements thus far. The technique has progressed to the point where, in 2018, more than 75% of patients are able to return home within 24 hours and nearly 1/2 return home on the day of surgery. 

Current data demonstrate that this procedure – combined with computer assisted surgical navigation - is actually safer than conventional total hip arthroplasty and results in a dramatically accelerated recovery (reference).  In fact, it is the only minimally invasive surgical technique that has been shown in the scientific peer-reviewed literature to be a safer procedure than the control group.   Recent economic research, both for patients insured by medicare and by a private insurance carrier sho that these patients treated by the superior hip approach combined with computer-assisted surgery have the shortest length of hospital stay, the lowest incidence of readmission, the lowest likelihood of needing post-operative skill-nursing facility care, and require the least amount of home care of any total hip arthroplasty patients in the state of Massachusetts.

The philosophy behind and evolution of this technique is described in many sources below. The first link below is a link to a video animation of the surgery. Although this video was developed for  orthopedic education, it gives you a good idea of the method even if you are not a surgeon.

Superior Capsulotomy Animation on youtube.

Please see below for more information about the philosophy and evolution if this surgical technique and also the other methods of performing "minimally invasive" total hip arthroplasty.  One of the most interesting aspects of hip surgery is that there are many good ways to accomplish the same goal.  Most of the methods of performing hip arthroplasty are described below as are links to additional publications. 

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Information about Less and Minimally Invasive Total Hip Arthroplasty Techniques:

Performing total hip arthroplasty while taking steps to minimize trauma to the surrounding tissues has great potential for facilitating recovery after hip replacement surgery.  

As noted above, I currently use tissue preserving, minimally invasive techniques when performing total hip arthroplasty in most situations.  For example, 197 of the last 200 procedures were performed using this technique.  Nearly all surgeries are performed with computer-assisted surgical navigation. Patients inappropriate for this surgery are generally those with more dramatic deformities and /or those with previous hardware or multiple previous surgeries. Importantly, patient size typically does not preclude one from qualifying for this method of tissue preserving surgery.

"Minimally invasive total hip replacement" is a broad term that is used to describe a wide variety of surgical techniques.

Some techniques are traditional operations performed through smaller incisions while others are fundamentally new operative techniques.

Some techniques are relatively safe while others have a track record of causing significant problems for a large percentage of patients.  Some techniques have even been largely abandoned due to fewer advantages than disadvantages.

If appropriate techniques are used by an experienced surgeon, minimally invasive total hip arthroplasty can be safe and very beneficial. The surgeon performing the operation together with his or her direct experience is of great importance when considering  minimally invasive hip replacement surgery.

Since "minimally invasive hip arthroplasty" can mean almost anything, it is important understand exactly what technique is being use.  Some understanding of the anatomy of the hip joint is required to appreciate the differences between techniques.

The hip joint is surrounded by a hip joint capsule which is much like a thick skin that surrounds the femoral head and socket. Outside the hip joint capsule are small muscles in the back of the joint called the short external rotators. The back half of the hip joint capsule and the short external rotators are important structures that serve to prevent dislocation following total hip arthroplasty.

On the side are the gluteus medius and minimus muscles that together are called the abductors. If these muscles are weak either before or after surgery, the patient will limp.

On the front of the joint there are several powerful muscles including the iliopsoas muscle, the sartorius muscle, the tensor fascia femoris muscle, and the rectus femoris. These muscles allow the leg to be lifted forward in a lying, sitting, or standing position.

There are many ways a surgeon can access the joint to perform a total hip replacement which makes the hip a very interesting joint to work on, but a bit confusing to anyone who is not a surgeon.  

Listed below is a brief description of common hip exposures together with my personal view of their respective advantages and disadvantages.  These descriptions will allow you to better appreciate why we developed the superior capsulotomy technique for most primary and selected revision arthroplasty procedures.

The Posterior Approach

The posterior approach is probably the most common surgical technique used for hip arthroplasty in the U.S. today.  Basically, the back half of the hip joint capsule and short rotators are incised to provide access to the joint. This surgery is safe, reliable and in most cases can be completed very quickly and easily.  The downside of this technique is a greater risk of dislocation – due to the fact that the back of the hip joint capsule and short rotators are incised.  In fact, this technique has the highest incidence of hip dislocation.

Two methods are used try to compensate for this at problem. One is to instruct the patient to restrict hip joint motion after surgery by giving the “dislocation precautions”. The second is to attempt to repair the hip joint capsule and short external rotators to their original state.  Importantly however, even if both of these methods are used, the patient cannot pursue unrestricted motion after surgery as the repair could disrupt. Since unrestricted motion is one of the important goals when trying to improve a patient’s post-op experience this method doesn’t really afford the opportunity to achieve that goal.

Many surgeons employ what is called a mini-posterior exposure – which is essentially the same technique performed through a smaller incision -but each of the limitations list above still apply.

The Direct Lateral Exposure

The Direct Lateral Exposure is another common technique for hip replacement surgery. From 1991 to 2002 it was also the exposure that I routinely used to perform hip replacement surgery and during that period, I felt it was the best exposure for most routine total hip replacement operations.

The technique involves spreading the gluteus medius muscle fibers and moving the front part of the gluteus medius, hip joint capsule and gluteus minimus muscle from the front of the femur. The implants are then inserted through this interval.

The advantage of this technique is that the back half of the hip joint capsule and the short external rotators are undisturbed and as a result, the hip is extremely difficult to dislocate. Specifically, the incidence of dislocation is less than 1 in 200, even when the patient is not advised to restrict hip joint motion in any way. Once the gluteus medius and gluteus minimus muscles heal, the hip joint is very close to its preoperative state, with all of the important muscles around the hip joint back where they were. I still feel that this is the best technique for total hip replacement in certain patients.  

The disadvantage of this technique however, is that the patient must protect the muscles around the hip after surgery to ensure that proper healing takes place.  The problem is that a lot of people don’t have very much pain a few weeks after surgery and prefer not to use their crutches. Bearing weight too early causes muscle contraction that can pull the muscle repair apart before it heals. This can lead to a limp and pain. The ideal hip operation would enable the patient to tolerate both unrestricted motion and unrestricted muscle contraction immediately after surgery. Needless to say, this is very rare.

The mini-direct lateral approach can be considered a minimally invasive technique too, but again, it is basically the same operation through a smaller incision. If you are really interested in how this surgery is performed, the Video Journal of Orthopedics, together with the Journal of Bone and Joint Surgery, produced a video that recorded me performing one of these operations. It is available on line at http://www.vjortho.com/cgi/content/abstract/4059.

The Anterolateral Exposure

The anterolateral exposure is a surgical method that allows for hip surgery to be performed through an interval that is behind the tensor fascia femoris muscle and in front of the gluteus medius and gluteus minimus muscles.  This method give good exposure to the socket and a little more challenging exposure to the femur.  Using the method described by Rottinger, the hip is turned outward during surgery to a degree that is greater than the motion that a normal hip joint would allow.  The more it is turned outward, the better the access to the femur.  Certain types of curved implants and instruments make this operation easier but it it much more challenging to implant some components into the femur without injuring the gluteus minimus musles and sometimes the gluteus minimus and tensor.  Rehabilitation following this technique can be rapid.  Some residual pain in the front of the hip is perhaps a bit more common in the long run than with other methods.

The Anterior Exposure

Anterior exposures to the hip joint have been routinely used since the inception of hip surgery, long before hip replacement was invented and has gained increasing popularity in the last several years.  This technique was originally employed mainly for cup arthroplasty surgery - an earlier version of hip prosthesis surgery.  It was always a common method of performing hip arthroplasty in some parts of France, particularly Paris.  Anterior exposures to the hip have also always be used for some forms of joint preserving surgery such as periacetabular osteotomy for hip dysplasia or surgery to relieve femoro-acetabular impingement.

Minimally-invasive total hip replacement surgery using the anterior exposure is becoming increasingly popular in Europe and in some parts to the United States. Joel Matta, M.D. from Los Angeles and William Hozack, M.D. from Philadelphia have used this method very effectively for their patients.

The anterior exposure for total hip replacement is especially good for placement of the socket component but it has significant limitations for implantation of the femoral stem component into the femur. The known limitions of the procedure include a higher incidence of wound problems (since the incision crosses the flexion crease), possibly a higher incidence of infection, a higher incidence of femur fracture and greater trochanteric fracture, and a higher incidence of abnormal function of the lateral femoral cutaneous nerve. Even given these issues, it can be a very effective technique when performed by a skilled and experienced surgeon. Dr. Murphy uses this surgical technique for certain types of joint preserving surgery such as periacetabular osteotomy, but not for prosthetic hip arthroplasty.

The Two Incision Minimally Invasive Techniques

A number of two-incision surgical techniques exist but perhaps the best known technique was popularized out of Rush-Presbyterian Hospital in Chicago. The approach - which received a lot of media attention in 2002 and 2003, is used by very few surgeons in 2010. It involves placing the socket in through the front of the hip joint and putting the femoral stem in through a small incision in the back.

Since its introduction, my personal opinion has always been that this technique is not as reliable as it needs to be and is potentially very harmful. There is general agreement on this point of view now which is why the technique is used much less frequently now than it was 5 or 6 years ago. The basic problem is that, while it is easy to put the cup into the socket, the stem is placed into the femur in a blind fashion because it cannot be directly seen by the surgeon. The abductor muscles are perhaps the most important muscles around the hip joint and they are not directly visualized or protected during surgery. This means that they are susceptible to injury which can be a very dramatic problem for some patients who have had this surgery. One recent study showed that muscle injury from this particular minimally invasive technique was much greater and much more variable than for traditional techniques. Mardones et al, Muscle Damage After Total Hip Arthroplasty Done with the Two-Incision Minimally Invasive and the Mini-Posterior Techniques. A more recent prospective randomized study demonstrated that there were no advantages of this technique as compared to a miniposterior exposure in terms of length of stay or recovery.

The second major problem is that the fit between the femoral stem and the femur itself is a critical issue. If the stem is not firmly fitted, it can loosen right away. If the stem is too firmly fitted, the femur can break. Very skilled surgeons who have adopted this technique have reported breaking the femur in 20% of patients when they first starting using this method. If such an event occurs, the incision must be extended beyond what would have been necessary had the patient and surgeon elected a more traditional approach in the first place.  In addition, if any of the soft-tissues that surround the opening in the femur get interposed between the femur and the femoral prosthesis when it is inserted, then the femoral bone may never have a chance to grow into the surface of the prosthesis.

The third problem with this technique is that it can’t be applied to the vast majority of patients in need of hip replacement surgery. Many patients, for size or other reasons, are not candidates for this type surgery.  

While this technique gained popularity from 2001 to 2003, it has been progressively abandoned by surgeons who previously embraced it due in large part, to the limitations noted above.

The concept of Tissue Preserving Total Hip Arthroplasty

The popularity of and considerable patient focus on  minimally invasive hip replacement techniques must be considered in terms of what  is and is not important.

Hip replacement surgery in its traditional form is superbly reliable. If we are going to try to improve it, we have to protect patients from any significant increase in the likelihood of being worse off than they would have been had traditional techniques been employed. What is really important is to allow patients unrestricted motion after surgery (as patients can have with the direct lateral approach) and to allow unrestricted muscle strengthening after surgery (as patients can have with the posterior approach). It is also important to be able to see and protect the major muscles around the joint and to be sure that the components fit and are well seated, without breaking the bone. If this is accomplished, patients will recover rapidly and reliably.

Starting in the Fall of 2002, with increased focus on precise placement of hip replacement components while minimizing the impact on the surrounding soft tissues, it became clear that the femoral stem could be inserted through a small incision in the superior hip joint capsule, behind the strong abductor muscles and in front of the posterior capsule and short rotators. This was done by preparing the femur for the stem before the femoral head was removed.

The advantages of doing this became progressively clear and they include the following:

The femur is more stable and stronger if the head is still in place which makes it less likely that the femur will crack during surgery.

Exposure is easier since instruments can be placed around the neck of the femur as it is still in place.

The hip never needs to be dislocated to complete the surgery. This means that the leg is never placed in a distorted position at any point during the surgery. This also means that the surrounding tissues don't need to be disturbed as much.

With the stem being placed through a small incision in the superior hip joint capsule, the cup was initially placed through the front - underneath the strong abductor muscles, through the anterolateral interval.

This method allowed insertion of the components while preserving all of the important structures around the hip joint – the posterior hip joint capsule and short rotators that protect against dislocation, and the abductor muscles that provide the strength for walking without a limp. This technique also proved beneficial in that it allows patients to more quickly and easily recover. After gaining more experience with this method in 2002 and early 2003, it also became clear that if the right surgical instruments were designed, that both the socket and the stem could be safely implanted through a single incision in the superior hip joint capsule - in between the short external rotators and abductors in nearly all patients. After we made those instruments, the second incision became unnecessary.  Dr. Murphy's invention of this surgical technique was unique to the point that two patents were issued by the the US Patent and Trademark Office in 2005 and 2006. 

The surgical technique and clinical results of this method have been presented at many national and international meetings and have been published in several journals and textbooks, including peer-reviewed scientific journal (Clinical Orthopedics and Related Research).

This work was recognized by the International Society for Computer Assisted Orthopedic Surgery in 2005 with the award for Best Clinical Presentation at the Annual Meeting in Helsinki, Finland.

While there are many ways to access the hip joint to perform a total hip replacement, the superior capsulotomy method may be the safest and most efficient way to preserve and protect all of the important structures around the hip joint and to facilitate both early recover and long term function.

The following links are all either manuscripts or abstracts that we have been published on the topic of tissue-preserving total hip replacement using a superior capsulotomy. They are generally listed from most recent to least recent. Please note that publications posted are for educational purposes only and should not be reproduced without permission of the publisher.

Murphy SB, Ecker TM, Tannast M. THA Performed using Conventional and Navigated Tissue-preserving Techniques. Clinical Orthopedics and Related Research. 453, pp. 160-167. 2006.