A Muscle Sparing, Minimally Invasive Hip Replacement

Dr. Steven Morgan

“I prefer to perform Hip Replacements via the anterior muscle sparing approach. Though uncommonly used in the United States, the anterior approach for total hip replacement provides multiple advantages for the patient”.

  • Incision is small
  • No muscles are cut or damaged
  • Dislocations are minimized
  • Precise implant positioning
  • Leg length is controlled
  • Hospital stay is shorter
  • No after operation restrictions
  • Immediate return to activity

History of the Anterior Approach in North America

Anterior approach hip replacement was first performed in Paris, France by Prof. Robert Judet using the Judet orthopedic table. Since the first surgery over 50 years ago this approach was largely performed only in France. The procedure was brought to North America by Dr. Joel Matta, in 1996 who had observed anterior hip replacement in Paris, and rethought his approach to hip replacement. Dr Matta’s philosophy in abandoning the posterior approach and adopting the anterior approach was to lower the chance of dislocation, improve recovery rate, and increase the accuracy of placement of the implants and restoration of leg length. Dr Matta has demonstrated over time the benfits of the approach as previously noted and has taken the time to educate and train orthopedic surgeons who have an interest in helping patients achieve the benefit of the Procedure.

What is the anterior approach ?

The anterior approach is an approach to the front of the hip joint as opposed to a lateral (side) approach to the hip or posterior (back) approach. It is a true anterior approach to the hip and should not be confused with other anterior like approaches that either require the cutting of muscle (The Harding Approach) or approaches that require the cutting of the Bone (Trochanteric Osteotomy). Because the direct anterior approach does not require that any structure to be cut there is less pain and no healing of the tissues required. This results in a faster rehabilitation, less time in the hospital and quicker return to activity.

Minimally Invasive

The normal incision is about 5 inches but may vary (shorter or longer) according to a patient's body size. Though small incisions are often considered desirable by patients, it should be kept in mind that the degree and type of tissue disturbance beneath the skin is a more important factor. Incisions of adequate length allow the necessary side-to-side separation of the incision without undue force. Too small an incision can be more traumatic to the tissues, particularly to muscles that can be damaged by stretching too hard.

Fracture Table

A fracture table is utilized because it allows us to manipulate the leg in a controlled fashion and expose the bones in a way that allows us to use smaller incisions and not cut any muscle. The table is used by surgeons who fix fractures of the Pelvis and the Acetabulum. It is not a common table, is expensive and is not available at many facilities. The procedure can be performed without the table but the advantages of minimizing trauma to the tissues and obtaining x-rays is lost. The fracture table is pictured below.

Fracture Table
picture courtesy of MIZUHOSI

X-Ray

With the anterior approach the patient lies supine (on their back) during surgery. X-rays taken during surgery with a fluoroscope to ensure correct position, sizing and fit of the artificial hip components as well as correct leg length and off set of the hip. The use of x-ray allows us to recreate the bodies normal positioning of the hip. This re-establishes normal muscle tension and normal mechanics of the hip joint. When the hip replacement is performed in anatomic alignment with that of a normal hip, the chance of dislocation, abnormal wear of the new hip, problems like squeaking or dislocation, and a difference in leg lengths is minimized. The use of an xray machine to minimize these problems is not possible with other surgical approaches, and the patient can ot benefit form this level of precision.

Rehabilitation

Rehabilitation is accelerated and hospital time decreased because the hip is replaced without detachment of the muscle from the pelvis or femur. Other surgical approaches necessitate detachment of multiple muscles from the femur during surgery. In the anterior approach, by contrast, the hip is approached and replaced through a natural interval between muscles. The most important muscles for hip function, the gluteal muscles that attach to the posterior and lateral pelvis and femur, are left undisturbed.

Evaluation and treatment by a physical therapist begins the day of surgery and leads to walking and functional activities. Patients may go home after achieving an initial degree of independence in walking with crutches or a walker as well as capabilities in basic day-to-day activities. Patients are commonly discharged 2 to 5 days following surgery depending on their degree of disability prior to surgery and their overall capabilities.

Dislocations

Lack of disturbance of the lateral and posterior soft tissues also accounts for immediate stability of the hip and a low risk of dislocation. It is normal for patients undergoing lateral or posterior incisions to follow strict precautions that limit hip motion for the first two months after surgery. Most importantly, they are instructed to limit hip flexion to no more than 60 degrees. These limitations complicate a patient's simple daily activities such as sitting in a chair or on the toilet or getting in a car. Following the anterior approach, however, patients are immediately allowed to bend their hip freely and avoid these cumbersome restrictions.

Sexual Activity

If patients are sexually active before surgery, there are no limitations on resumption of sexual activity after surgery.

Why is this approach not more commonly used in the United States?

There are several reasons this approach to hip replacement is not used. The traditional technique utilizing a posterior approach is what has been taught to surgeons for many years. It takes a surgeon with a special interest and desire to learn the technique. The technique requires the use of a special operating table known as a fracture table. The fracture table is very expensive and not available at many hopsitals and not familiar to many surgeons. The fracture table allows precision control of the hip during the surgery, and makes it possible to utilize x-rays. X-rays are used during surgery to insure that the implants are placed in the correct position and that the legs will be of equal length. The use of the fracture table and x-rays adds some additional time to the surgery. Not everyone wants to spend the extra time doing the hip replacement.

Dr Morgan’s Philosophy and Training in Anterior Hip Replacement Surgery

Dr. Morgan was trained in Orthopedic Surgery at the Los Angeles County University of Southern California Orthopedic residency Program. He received additional Training in Orthopedic Trauma Reconstruction at Carolinas Medical Center after residency. Dr Morgan’s practice has been focused on surgical repair of traumatically injured extremities, the pelvis and acetabulum, and hip replacement surgery for the past 12 years at Denver Medical Center. Prior to leaving Denver Health in 2010 and recognizing the same potential benefits that Dr. Matta had in 1996, he developed an interest in anterior hip replacement. After observing Dr. Matta in 2009 and recognizing the benefits of the approach, the surgical technique has become the preferred approach for hip replacement in qualified patients. The familiarity with the pelvis and acetabulum as well as a broad experience in hip replacement made transitioning to the anterior approach easy. The use of the fracture table and the use of fluoroscopy during surgery is second nature. The use of the anterior approach allows the surgeon to utilize all available tools, such as the fracture table and x-ray, to insure that the patient has optimal implant positioning and reduced dislocation risks only makes sense.