Posterior Approach Hip Replacement: What “Muscle-Sparing” Really Means

Start here: what the traditional posterior approach divides

To judge whether a newer technique is truly “muscle-sparing,” it helps to know what the original posterior approach actually cut. The traditional posterior approach to the hip, sometimes called the Moore or Southern approach, has been performed for decades and reaches the joint from the back by passing through several layers in turn:

• The iliotibial band and fascia lata. The thick fascial layer on the outer side of the hip and thigh is split to begin the exposure.
• The gluteus maximus. The large muscle of the buttock is then split in line with its fibers to reach the deeper layers.
• The short external rotators. These small but important muscles at the back of the hip are released from the femur, usually the piriformis along with the conjoined tendon of the superior gemellus, obturator internus, and inferior gemellus. They are typically reattached at the end of the operation, and they are part of what holds the hip stable against dislocation.

That is the baseline. Every “muscle-sparing” posterior variant is defined by how much of this list it manages to preserve. As you will see, they each save one or more of these structures, which is a genuine improvement, but none of them avoid the second item on the list. They all still split the gluteus maximus.

The short answer

The posterior approach reaches the hip from the back of the joint. It is a long-established and widely used technique, and the newer “muscle-sparing” variants are real refinements that preserve some structures the traditional version did not. But there is one anatomic fact none of them can get around: every posterior approach to the hip splits the gluteus maximus, the large muscle of the buttock. There is no path to the hip from behind that avoids it.

So when a posterior technique is advertised as not cutting muscle, the honest reading is that it spares certain muscles, usually the smaller external rotators, while still dividing the largest muscle in the region to get to the joint. The only approach that reaches the hip without splitting or detaching a muscle is the front, the direct anterior approach.

The claim being marketed

Several posterior-based techniques are now promoted with muscle-sparing branding, in large part to answer the rise of the anterior approach. The common ones include:

• STAR (Superior Transverse Anatomic Reconstruction), a piriformis-preserving mini-posterior approach.
• SuperPath and the related SuperPATH and PATH techniques, marketed as supercapsular, percutaneously assisted approaches.
• The direct superior approach (DSA), a mini-posterior approach that spares the iliotibial band.
• Piriformis-sparing posterior approaches, which preserve the piriformis tendon.

These approaches genuinely do preserve structures that the classic posterior approach sacrifices, and that is a worthwhile goal. The problem is the headline. Sparing the piriformis or the iliotibial band is not the same as not cutting muscle, and presenting it that way leaves patients with a false impression of how the operation compares with the anterior approach.

The one fact the marketing skips: they all split the gluteus maximus

This is not a matter of opinion, and it is easy to confirm from the published surgical descriptions of each technique. In every posterior-based approach, the surgeon splits the gluteus maximus to reach the deeper layers of the hip:

• The STAR technique is described by its own authors as using a gluteus maximus split while preserving the piriformis and repairing the other short external rotators.
• The SuperPath and direct superior techniques describe splitting the gluteus maximus bluntly, in line with its fibers, before working through the deeper interval.
• Piriformis-sparing and conventional posterior approaches likewise split the gluteus maximus in line with its fibers.

Splitting a muscle in line with its fibers is gentler than cutting across it, and that is a fair point in these techniques’ favor. But it is still going through the muscle. A patient told an operation is “muscle-sparing” would reasonably assume no muscle is divided at all, and for any posterior approach that assumption is incorrect.

To be fair: what these approaches do spare

It would be just as misleading to pretend these techniques offer nothing. Compared with the traditional posterior approach, the muscle-sparing variants aim to preserve the piriformis and the other short external rotators, and some preserve the iliotibial band. Preserving those posterior structures may improve early hip stability, and several studies report short-term benefits such as less blood loss, shorter hospital stays, and faster early recovery. Those are real, and Dr. Dattilo does not dispute them.

The point of this page is narrower and specific: these are still posterior approaches that split the gluteus maximus, and describing them as muscle-sparing in a way that implies they rival the anterior approach for tissue preservation is misleading.

Why the anterior approach is genuinely different

The direct anterior approach reaches the hip from the front, through a natural interval between muscles. It is what surgeons call intermuscular and internervous, meaning the surgeon works in the plane between muscles rather than splitting or detaching any of them, and without crossing the nerve supply to those muscles. No muscle is divided to reach the joint. This is the anatomic reason the anterior approach is recognized as a true soft-tissue-sparing technique, and it is the distinction the posterior “muscle-sparing” branding tends to blur.

Dr. Dattilo performs the direct anterior approach, including a bikini-line incision option, for his primary hip replacements.

An honest word about outcomes

Being straight with patients cuts both ways. Across large studies and national registries, the differences between hip replacement approaches tend to even out over the long term, and a well-done hip replacement through any standard approach can give an excellent result. The anterior approach’s best-supported advantage is a faster, more comfortable recovery in the first few weeks, which matters to most patients, rather than a different result years down the line. Surgeon experience and accurate implant placement matter more than the label on the technique. The reason to prefer the anterior approach is the anatomy of how it reaches the hip, not a promise that it is the only way to a good outcome.

Dr. Dattilo’s practice and philosophy

Dr. Dattilo is fellowship-trained in adult hip and knee reconstruction at the Anderson Orthopaedic Research Institute. His practice reflects a deliberate philosophy about hip replacement:

• He performs his primary hip replacements exclusively through the anterior approach, the one approach that reaches the hip without splitting a muscle.
• He performs the majority of his hip revisions through the front as well. He believes a surgeon should be comfortable handling the hard cases and the complications through the anterior approach, rather than reserving it only for the straightforward cases and reaching for another approach when things get difficult.
• He uses the posterior approach selectively, where it is the right tool, primarily in revision cases that require direct access to the back of the socket (the posterior acetabulum). Choosing the posterior approach when the anatomy of a complex revision calls for it is sound surgical judgment, not a contradiction.

The throughline is simple. The approach should be chosen for the patient and the problem, and a surgeon should be capable across the full range of cases, not only the easy ones marketed for a minimally invasive technique.

The bottom line for patients

If you have seen a posterior hip replacement advertised as muscle-sparing, it is reasonable to look closer and to ask direct questions before deciding:

• Does this approach split the gluteus maximus to reach my hip? (For any posterior approach, the answer is yes.)
• Which muscles does it actually spare, and how does that compare with the anterior approach, which goes between muscles?
• Are you fellowship-trained in joint replacement, and do you also handle revisions and complications, not just routine cases?
• Which approach is right for my hip, and why?

Dr. Dattilo is glad to walk you through the anatomy honestly and tell you which approach fits your hip. More on how to choose a hip and knee replacement surgeon ›

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