Feature Articles

Minimally Invasive Hip Replacement
Using the Anterior Approach

     A Q&A session with Kristaps Keggi, MD, a world pioneer of minimally invasive anterior hip replacement.

What is minimally invasive hip surgery?
Simply put, it means using small incisions. In the case of hip replacement surgery, it means a two- to three-inch scar versus five- to seven inches.  The skin incision is important.  It should be as short as possible, but as long as necessary to do the operation well.  Muscle sparing under the skin is probably as important as a short incision.  Another way to think of it is as the Muscle Sparing Approach (MSATM)

What is minimally invasive anterior hip replacement?
Anterior hip replacement involves inserting the hip prosthesis from the front of the hip joint, with the patient facing up, as opposed to the lateral (side) approach or the posterior (back) approach.

What are the advantages to the patient?
One of the biggest advantages of the anterior approach is a small incision, possible because there is less fatty tissue and muscle in the front of the body near the hip joint. This means less surgical cutting and disturbing of tissue and muscle and less blood loss. Depending on the individual patient and the type of prosthesis being used, one to two incisions are made, about two inches each.

What are other advantages of the anterior approach?
Because the small incisions afford less trauma to the body, healing and rehabilitation can begin sooner. Patients begin rehabilitation immediately and typically have a three to four day hospital stay. Lack of disturbance to the lateral (side) and posterior (back) soft tissues also allows for immediate stability of the hip and low risk of dislocation. That means less risk of needing to repair or revise the new hip joint.

How common is minimally invasive anterior hip replacement?
The anterior approach is still relatively uncommon in the United States. One reason is a lack of familiarity with the technique because traditional surgical methods are slow to change.

While the anterior approach is most beneficial to the patient, it is harder technically on the surgeon. Working within a small incision requires special dexterity and skill. However, with new devices and modifications of surgical instruments, I expect that the anterior approach will become more common, driven in part of consumer demand for minimally invasive surgery in all specialties.

How long has the anterior approach been used?
Small-incision hip surgery is not new. The anterior approach to surgery on the hip has been well documented by many doctors long before it was applied to actual hip replacement. I began using the technique for total hip replacement in the 1970s. My colleagues and I first presented our experiences with the anterior approach to the American Academy of Orthopaedic Surgeons (AAOS) in 1977, and since then we have published many studies and articles detailing this technique.

How many anterior approach surgeries have you done?
I have performed the technique approximately 4,500 times in the last 30 years. I have trained about 300 Yale University School of Medicine orthopaedic residents and surgeons from the former Soviet Union in the technique. [The Soviet surgeons learned the technique as part of an exchange program through the Keggi Orthopaedic Foundation.] One of the surgeons who learned the technique as a Yale orthopaedic resident is my nephew John Keggi, MD.,  who has been in practice with me since 1995.  Dr Robert Kennon, who joined our practice in 2004 is also someone whom I had the pleasure of having as a student and researcher of the anterior minimally invasive or muscle sparing approach. 

What kind of results have you had? 
I've had excellent results, including significantly fewer blood clots, infections and dislocations, and faster healing and recovery times.

What kind of improvements have you made in the technique?
We have modified the approach over the past 20 years to maximize our ability to use various non-cemented prostheses. Right now we are experimenting with a type of prosthesis that can be fully assembled inside the body. Our operative times have been as low as 25 minutes and average approximately 45 minutes in simple, uncomplicated hips.

Who is a candidate for minimally invasive anterior hip replacement?
Almost everyone is a candidate. I have used the technique thousands of times in all types of patients, including the morbidly obese. We also use it in hip revisions, since it is easy to extend the incision to expose the entire femur.

How can I determine if I am a candidate for the anterior approach?
First locate an orthopaedic surgeon who is skilled in the technique. This is often done by word-of-mouth referral, since the number of surgeons using the technique in the U.S. is still small. The Internet can be helpful in locating doctors and centers that employ the technique. As with any surgery, it is often a good idea to obtain more than one opinion on the type of hip replacement that is best for you.