Hip replacements are carried out through one of several different surgical approaches. Over the decades, surgical approaches have been developed that go in through the front of the hip (anterior), between the front and side of the hip (anterolateral), the side of the hip (lateral, or transtrochanteric), and through the buttock (posterior). There are advantages and disadvantages to each, and there is a great deal of controversy among hip surgeons as to which is the "best." All surgeons have a favored surgical approach, and while there are often spirited debates at academic conferences and meetings, it is a testament to the success of the procedure that all of them generally produce good results.

Posterior Surgical Approach

The posterior approach, or Southern approach, is the most commonly used surgical approach for hip replacements in the United States today, although as more interest has been generated in recent years in minimally invasive techniques other approaches are increasingly being used. The patient is positioned on his or her side for this surgery, in what is called the lateral decubitus position.

This approach uses a large, curved incision centered over the buttock. It is usually the largest incision of all of the surgical approaches for any given patient, and requires splitting of the gluteus maximus muscle. The short external rotator muscles are completely detached from the femur, and the hip is dislocated. The femur is twisted around to the front of the patient and rotated inward expose the socket (acetabulum) and femur.

This surgical approach has the advantage of a very large exposure and visualization, but the disadvantage of significant muscle disruption. There is also a higher risk of blood clots because of twisting the vessels.

Some surgeons have recently been utilizing smaller incisions for the posterior approach, often using instruments designed to allow less surgical dissection, but the interval and muscles involved remain the same.

It is more difficult to perform bilateral (e.g., both right and left) hip replacements at the same time with this approach, as it requires repositioning during surgery and placing the patient on the freshly operated side. (In contrast, with an anterior approach, both hips may be replaced more easily during the same surgery, if necessary.) Many patients also note that the posterior incision is on the cheek of the buttocks and may be irritated by sitting.

In the posterior approach to the hip (the dark line over the buttocks), the patient is positioned
on his side (lateral decubitus position). This approach transects the gluteus maximus and
detaches several muscles, but allows wide exposure and visualization

Anterolateral Approach

This approach, also known as a Watson-Jones approach, typically uses a straight incision over the side of the hip, with the patient positioned on his side in a similar fashion as the posterior approach. The surgical approach goes straight down to the femur, but it does require stripping of the gluteus medius muscle from the femur to expose the hip joint. From there, it usually is not necessary to detach the short external rotator muscles, but the remainder of the procedure is similar to the other surgical approaches.

The anterolateral approach is thought by many surgeons to afford a lower dislocation rate than the posterior approach, but a frequent criticism of the approach is that many patients limp for a prolonged period of time while the muscles heal (gluteus medius and gluteus minimus).

Transtrochanteric Approach

When Sir Charnley first began doing hip replacements, he utilized this approach to enter the hip from the side, cut a portion of the femur away to expose the hip joint (trochanteric osteotomy), and then wire the bone back together with the muscles still attached at the end of the case. The approach is very similar to the anterolateral approach except that it involves cutting a portion of the bone (the osteotomy). However, it fell out of favor over the past several decades because of problems associated with reattaching the section of cut bone. It is mentioned for historical interest here, given that it is not commonly used any longer in most places.

Anterior Surgical Approach

The 2 incision anterior approach typically uses one or two smaller incisions over the front
of the thigh with the patient supine (laying flat on his back). This also facilitates
bilateral surgeries (working on both the right and left sides). The lower incision is used
to remove the femoral head (ball) and replace the acetabulum (hip socket).
The upper incision, if needed for a large or muscular patient, is used to place the stem in the femur

This is the surgical approach that we use in our practice. It involves making one, two, or on occasion (for very large patients, usually 300 to 450 lbs.) three smaller incisions over the front of the thigh.

The original anterior surgical approach, known as a Smith-Peterson approach, has been around for many decades. In the 1970's, Dr. Kristaps Keggi first developed and published the modified anterior approach that we utilize, making it one of the newest surgical approaches (while orthopaedic implant technology changes all the time, surgical approaches have changed very little in the past 100 years). This surgical approach has been taught to all Yale orthopaedic residents for nearly 30 years now.

In the past 5 to 10 years, there has been increased interest in the U.S. in the anterior surgical approach because of increased patient (and surgeon) interest in minimally invasive surgery. It provides the least disruptive surgical approach, but it is one of the more technically demanding approaches from a surgeon's viewpoint because of the need for increased awareness of the local anatomy and less visualization / exposure with the smaller incisions.

The incision can be either straight or curved, depending on the size of the patient's thigh, and is carried down to the tensor fascia. This fascia is split, and the interval between tensor fascia lata and the sartorius muscle, and then between the rectus femoris and gluteus medius muscles, is opened without having to cut across any muscles. This same approach can be extended proximally (towards the head) and distally (towards the foot) for revision surgeries and even total femur replacements (which are only done rarely, replacing the entire femur and both the hip and knee joints).

For large or muscular patients, a second, smaller incision (usually about an inch in length) is often made over the side of the thigh to pass the stem into the femoral canal so that a larger, single incision is not necessary.

There are a number of advantages to this surgical approach. Intuitively, it makes sense that there is significantly less muscle disruption in approaching the hip from the front and avoiding splitting the gluteal muscles in the buttocks. In fact, the approach only splits the tensor fascia, and then exploits a natural interval down to the hip joint itself, preserving muscle attachments. In contrast, the posterior approach still used in the majority of hip replacements today requires extensive muscle dissection through the gluteus maximus and complete detachment of the short external rotator muscles (piriformis, obturator externus, gemelli, quadratus).

Incidentally, with the anterior approach the incisions are typically significantly smaller and cosmetic, although it is the muscle dissection underneath the skin that is far more important in minimally invasive techniques.

Some surgeons have advocated using live x-ray (fluoroscopy) during the surgery with minimally invasive approaches, particularly this anterior approach. While it is certainly an option for a surgeon who is new to the technique or has any questions about positioning, we do not typically find the additional radiation and x-ray exposure to be justified in most routine cases. Our practice performs hundreds of replacements annually without using x-rays during surgery, but it is mentioned here because you may come across surgeons in some locations that advocate its use.

Some surgeons advocate computer navigation during surgery for the same reasons, although its utility has been debatable in many studies so far, and it is unclear if the benefits outweigh the drawbacks and increased operating time.

The anterior approach is performed with the patient laying flat (supine) on his or her back. This is important for several reasons; there is a lower incidence of blood clots because the hip is not twisted 120 degrees at odd angles as it is in some posterior approaches. It is simpler to match up the lengths of the legs when they are both straight rather than having the patient on his side for a posterior approach, and the surgeon can easily check that the patellae (knee caps) are even. This position also facilitates bilateral hip replacements, which we perform often, by only having to position and drape the patient once. In contrast, posterior approaches require repositioning and draping, and moreover, the newly operated incision is on the downside against the table while the opposite hip replacement is performed.

The anterior approach avoids the sciatic nerve that runs along the back of the hip, which is the most frequently injured with posterior approaches and can result in a foot drop post-operatively. However, a skin nerve in the front of the thigh (the lateral femoral cutaneous nerve) is at increased risk with the anterior approach, and may rarely result in a patch of numbness over the front of the thigh.

Commentary

In our review of over 2000 anterior total hip replacements by Dr. Kristaps Keggi, published in 2004, the direct anterior approach had a very low complication rate and excellent, rapid rehabilitation. In my opinion and that of many other orthopaedic surgeons specializing in joint replacement, this approach affords the most rapid rehabilitation available, although to be honest there are proponents of other surgical approaches who would dispute that claim. However, there is little disagreement that it does involve the least dissection of muscles.

The most common criticism of the direct single and two incision anterior approach is that it is technically challenging, and for this reason it is not often used by surgeons who do not specialize in hip surgery. Over 50% of all hip replacements in the U.S. are performed by community orthopaedic surgeons who perform one joint replacement a month or less, and in these situations it makes sense that a larger, posterior approach with better exposure and visualization would be used. However, if the same surgical approach is used three to six times per day, for hundreds of surgeries per year, it becomes easier to see why good results can be achieved by those who use it frequently. Not surprisingly, published studies in recent years have shown that outcomes are better and complications are fewer when total joint replacements are performed by surgeons who specialize in joint replacements and do the surgery more often, regardless of the surgical approach used.

Conclusion - Multiple Surgical Approaches Exist

In summary, there are multiple surgical approaches for hip surgery, and there are also multiple surgeons who advocate one particular approach over others. At our center, we do a great deal of research and publication regarding minimally invasive surgical techniques and feel strongly that the anterior (Keggi) approach has a strongly proven record of superior outcomes over the past three decades, but there are proponents of all surgical approaches at various centers.

If you have a preference for a particular surgical approach, it is in your best interests to look for a surgeon who uses it routinely rather than try to talk your surgeon into a surgical approach that he does not use often. In the end, the best advice for the patient is to find a surgeon whom you like and feel comfortable with, be sure that he has good surgical outcomes and a significant volume of hip replacements (preferably multiple hip replacements each week!), and allow the surgeon to use the surgical approach and technique that he is most accustomed to.

Please remember the information on this site is for educational purposes only and should not be used to make a decision on a condition or a procedure. All decisions should be made in conjunction with your surgeon and your primary care provider.