A New Direction in Hip Replacement

Almost a quarter of a million people in the United States have hip replacement surgery each year. In San Francisco, doctors at CPMC perform more joint replacement surgeries than any other hospital – experience that translates to better outcomes. And one of our surgeons, Nicholas Mast, M.D., is one of only a handful of doctors nationally to be fellowship trained in performing hip replacement using the anterior approach. What does that mean to his patients?

The Anterior Approach in hip replacement surgery allows the surgeon to reach the hip joint from the front of the hip as opposed to the lateral (side) or the posterior (back) approach. Doing this allows the surgeon to replace the hip without detaching any muscles. This means that the most important muscles needed for hip functioning are untouched, requiring no healing. This, in turn, allows the patient to recover much more quickly.

“There is decreased muscle trauma since we are not cutting into muscle,” explains Mast. “After surgery – even sometimes on the same day – my patients can cross their legs, reach down and scratch their toes. They don’t have to worry about restrictions that we’ve had to deal with for so many years.”

This improved recovery process often means patients go home quicker – patients having the anterior approach usually leaving the hospital a day earlier than other hip replacement patients.

“In general, the recovery rate is twice as fast as other approaches.” says Mast. “Our data tells us that the average time it takes patients to discard canes, crutches or walkers is 14 days. The most remarkable thing is our data reflects an array of patients – from athletes to great-grandmothers.”


Schriever still checks in with Nick Mast, M.D., who checks the flexibility of John's new hip.

CPMC has invested in a special surgical table for the anterior approach. The table makes use of modern carbon fiber composites and allows for the intraoperative use of x-ray to help position the replacement. “This technique allows me incredible control of implant position,” explains Mast. “The better we position the prosthesis, the longer the implant will last. One of the best predictors of the long term function of a hip replacement is how well it is positioned at the time of surgery.”

The table was designed with input from Joel Matta, M.D. whom Mast credits as one of the founding fathers of Anterior Approach hip replacement in North America. Mast spent a year working as a fellow, directly under Matta, where he performed 180 anterior approach procedures. To date, Mast has performed 500 anterior approach replacements – experience that translates to better outcomes.

Mast warns patients to do their research and select a surgeon with experience in the technique, which can reduce chances of complications. Furthermore, not all anterior approaches are the same. “Some doctors do an antero-lateral procedure, which means the patient is still lying on his side, the gluteus muscles are split and part of the abductor muscles have to be detached in order to dislocate the hip. This is not the same as the direct anterior, or Smith-Peterson approach, which I perform. Patients who have the antero-lateral approach may have difficulty healing the injury to the abductor muscles and may end up limping. The anterior approach means not cutting any muscle – which means less limping and faster return of normal hip function.”

Less disruption of muscle also means a lower rate of dislocation, which occurs when the prosthesis becomes uncoupled as the hip “pops out” of the socket. By preserving the muscular attachments to the hip, according to Mast, the risk of dislocation has been nearly been eliminated. “I have patients who have gone back to yoga classes and surfing, I don’t worry about them dislocating.”

John Schriever, 46, of Redwood City, is one of only a few patients who can actually compare procedures. In 2004 his doctor used the posterior approach to replace his left hip. Continued problems with arthritis required him to have his right hip replaced in 2010. This time, he selected Mast as his surgeon, and the procedure was performed with the anterior approach.

“The procedures were so different in terms of recovery,” explains Schriever, who was very active in baseball, basketball, water polo and racquetball when he was younger. “During recovery from the first procedure, I felt like I had been hit by a Mack truck from the doctor wrenching on my hip trying to dislocate it. They made an incision in my butt cheek and had to cut into and spread the muscle. That’s what hurt so much afterwards. It took me about 8-10 weeks to recover, though I was walking and climbing stairs in about four weeks. After about six weeks, I began a month of physical therapy.

“With my second operation, Dr Mast used the anterior approach – and I didn’t even need physical therapy. Within 4-5 weeks, I was working out again – using the stationary bike, lifting, doing leg exercises and leg lifts. No squats, though. Dr Mast made me wait 12 weeks till I could resume mountain biking.”

In addition to a quicker recovery time, the 6’2” Schriever says pain was minimal. “Because he didn’t cut muscle there was less pain.”

“As wonderful and advanced as these techniques and implants have become, they are still no match for the native human hip. The first thing I try to do when a patient comes to see me is to see if I can save the hip,” explains Mast. “There are procedures now available which can potentially prolong the life of the joint. California Pacific Medical Center has invested in technologies that have made this possible.”

This equipment, along with certain protocols, allows Mast to evaluate a patient’s hip and cartilage. “We are able to predict the responsiveness of a patient’s hip to conservative surgical and arthroscopic treatment. Using advanced imaging modalities we can predict who will respond to what approach and tailor treatment to what the patient needs.”

They key factor is timing. Explains Mast: “If you can correct the cartilage problem early on through conservative surgical treatment, we can preserve the hip – and potentially delay the need for a hip replacement. The problem is, many people just wait too long before seeing a surgeon.”

About the Joint Replacement Center - CPMC, San Francisco

The Joint Replacement Center is a branch of the Department of Orthopedic Surgery, based in San Francisco, California and treating patients in San Francisco, Marin County, Oakland, and throughout the greater San Francisco Bay Area. Our top orthopedic surgeons provide specialized surgical services for treating conditions of the hip, knee and shoulder. We consider our surgical team to be among the best surgeons, physicians, nurses, and doctors, working together to provide personalized treatment plans for procedures such as joint replacement, total or partial knee replacement surgery, total or partial hip replacement surgery, shoulder surgery and even elbow surgeries. If you are looking to consult with one of the top Bay Area joint, hip, knee, elbow or shoulder surgeons, reach out and make an appointment. The first step towards finding the best surgeon for you is an initial consultation.
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