Muscle-sparing direct anterior approach to hip replacement

The direct anterior approach to total hip arthroplasty is not a new procedure, but its popularity has skyrocketed in recent years, says Kimberly L. Stevenson, MD, who joined the Penn Medicine Physician Interviews Podcast to discuss the advantages of this approach to hip replacement, and which patients are good candidates. Dr. Stevenson is an orthopaedic surgeon specializing in adult reconstruction, and serves as Chief of Orthopaedics at Penn Medicine Chester County Hospital.

While a variety of hip replacement strategies, including lateral and posterior approaches, are available, surgeons and patients are increasingly opting for the direct anterior approach, says Dr. Stevenson, who uses the approach for most of the hip replacements she performs.

Benefits of the direct anterior approach for total hip arthroplasty

The direct anterior approach is known for several key benefits. Among the reasons Dr. Stevenson favors the approach is that it’s considered muscle-sparing, she explains. Lateral and posterior approaches require splitting the gluteus maximus muscle to gain access to the hip. “That matters because this is a large, functional muscle. When it’s split, patients can require additional rehab.”

Using the direct anterior approach, the surgeon accesses the hip between muscle planes. “That leads to one of the main advantages of the direct anterior hip replacement, which is faster recovery,” she says.

Moreover, with other approaches, patients are generally required to follow posterior hip precautions for six weeks after surgery, including not bending forward past a 90-degree angle or adduction past the midline. During this time, patients also engage in rigorous physical therapy.

“With direct anterior hip replacement, I don’t give my patients any hip precautions, starting from day one,” Dr. Stevenson says. “They can sleep how they’re comfortable and sit how they’re comfortable—and this is very liberating and freeing for the patient.”

Additionally, many patients don’t require physical therapy following the direct anterior approach, since the muscles are spared. For most of her patients, the only post-surgical precaution she recommends is to use a walker or cane for the first week or two, purely as a means of fall prevention. “Typically, by six weeks, patients are feeling fairly back to normal and ready to progress their activity from where they were even before surgery,” she says.

Direct anterior hip replacement may also help to protect against dislocation, Dr. Stevenson notes. That makes it a good option for people at higher risk of dislocation, such as patients who have had spinal fusions.

Who is a good candidate for direct anterior hip replacement?

Despite the benefits of direct anterior hip replacement, the approach is not the best option for everyone. Patients with more soft tissue distribution around the hip may not be good candidates because soft tissue overhang can lead to difficulties in wound healing, Dr. Stevenson explains. “There isn’t a specific BMI or weight cutoff, but we do take into consideration where a patient carries their weight.”

In addition to wound healing complications, obesity can increase the risk of fracture because regardless of the size of the patient, the incision is quite small. Thus, if the patient has a larger soft tissue envelope, Dr. Stevenson says, it may put extra stress on the bone and increase fracture risk.

Given the fracture risk associated with the direct anterior approach, surgeons should also consider comorbidities such as osteoporosis and osteopenia, says Dr. Stevenson. “They do not preclude someone from this approach, but it’s an extra consideration and conversation to have with those patients.”

Regardless of the approach, the most important thing patients can do to prepare for a hip replacement is maintain overall conditioning and mobility as much as possible. “Maintaining musculature and strength around the hip is important for rehab,” she says.

Growing popularity of direct anterior hip replacement

Although direct anterior hip replacement was introduced in the 1940s, it was popularized in the early 2000s after the development of a special table that facilitates the approach.

Even with that equipment, however, the direct anterior approach has a steep learning curve, Dr. Stevenson cautions. “It takes a hundred-plus cases to see a decrease in complications and a lower operative time, which is a measure of proficiency,” she says. For that reason, it can be challenging for established surgeons to adopt the approach.

Today, though, most trainees going through residency and fellowship are learning direct anterior hip replacement as the predominant approach, increasing the pool of skilled surgeons who can offer the specialized procedure. “Despite the increased learning curve for this approach, the key benefits for a patient far outweigh the risk,” Dr. Stevenson says. “I think this approach will only continue to grow.”

She encourages any patient who is limited by hip pain and/or stiffness to consider hip replacement. “For anyone who is active, who has goals to become more active, or even patients who are at increased risk of dislocation, I believe direct anterior hip replacement is an excellent option,” she says.

Penn Medicine’s skilled orthopaedic surgeons partner closely with referring providers through individualized patient evaluation, total hip arthroplasty, and coordinated perioperative care.

Referrals and consultations

For a provider-to-provider consultation with Dr. Stevenson, call 877-937-7366, or refer a patient online.