Approaches to Total Hip Replacem Approaches to Total Hip Replacement Surgery
James W Pritchett, MD Chief of Orthopedic Surgery, Swedish Orthopedic Institute; Active Staff, Swedish Medical Center
In 1939, Dr. Marion N. Smith-Peterson originated and popularized the direct anterior approach to the hip for placing hip prostheses. For many years, the approach was called the Smith-Peterson approach. It was known to be a relatively bloodless, direct, muscle-sparing approach into the hip that provided good visualization of the acetabulum. Smith-Peterson used a resurfacing femoral head prosthesis that had no stem. As stem-supported femoral prostheses were developed, placing them in the femur using this approach became more challenging.
Positioning the femur to achieve direct access to the femoral shaft requires the use of a curved femoral prostheses. Many of the early total hip prostheses had a curved stem, and the anterior approach was used. With the development of longer and straighter femoral stems, other approaches also became popular.
Currently, 3 approaches are commonly used for total and partial hip replacement and hip resurfacing.
The posterior approach is quite popular because of its ease and direct access to both the acetabulum and extensile access to the femur. The patient is placed in a decubitus position, and a curved incision following the direction of the gluteus maximus muscle is made. This muscle is carefully retracted, and the small external rotator muscles are detached from the greater trochanter and are preserved for later reattachment.
Postoperatively, the skin incision is not very apparent, and cosmetic concerns are rarely an issue. The hip is dislocated by flexion and internal rotation, and both the femur and acetabulum come into direct view even with smaller incisions. The other two approaches are the anterolateral and direct anterior.
No controlled studies describe convincing proof that one approach is superior to another. However, postoperative hip instability is less of a concern with the direct anterior and anterolateral approaches compared with the posterior approach. In addition, the anterolateral approach has the lowest complication rate of the 3 common approaches (ie, direct anterior, anterolateral, and posterior).
The direct anterior (Smith-Peterson) approach is made with the patient in the supine position. The entire hip and leg can be dropped free or the patient’s feet can be placed in traction to assist in working inside the femur. The approach and positioning maneuvers are the same with or without the traction table.
The skin incision is made anteriorly using the anterior superior iliac crest as a landmark. The incision is extended distally, as needed. The surgical approach is between the tensor fascia lata and sartorius muscles, so the approach is muscle sparing. The dissection is carried down the joint capsule, which is opened. If the tendon of the rectus femoris is a barrier to dislocating the hip, it is released and repaired later. The lateral femoral cutaneous nerve is directly in the way for the anterior approach. Identifying and retracting this nerve is important to avoid including it in the closing repair. Numbness and pain from this nerve are common with the anterior approach, but motor function is not affected.
Once the hip joint is entered, the hip is dislocated by adduction and external rotation. After the femoral head is dislocated, it can either be removed using a saw for total hip replacement or resurfaced. With the femoral head removed, direct access to the acetabulum is available, and the acetabular component can be placed with direct visualization and, if desired, with intraoperative radiographic imaging, as well.
The access to the femur is created by bringing the femur into external rotation, adduction, and extension. For surgeons who used a special table, achieving additional extension by dropping the patient’s operative leg below the height of the table is helpful. The use of the table requires a skilled assistant to avoid injury to the patient.
Usually, use of a curved femoral stem and preparation tools to work inside the femur are still needed. Current survivorship data support the use of a curved femoral prostheses as comparable to straight stem prostheses. Special offset broach handles are very helpful for anterior hip approaches.
The anterolateral approach to the hip has been one of the most commonly used approaches for total hip replacement around the world for the last 40 years. It provides excellent and safe access to the hip, and hip dislocation following the anterolateral approach has been uncommon. No special tables or instruments are necessary for anterolateral approaches, although broach handles can facilitate the approach.
The patient is placed in a supine or, if desired, a lateral position on the operating table. A straight lateral incision is made, and dissection down to the fascia lata follows. The interval between the vastus lateralis and abductor muscles is developed. The abductor can be released and repaired later with the closure. The hip capsule is identified and opened, and the hip is dislocated by traction and external rotation. The femoral head is then removed, allowing direct access to the acetabulum. The femur is placed into a figure-of-four position for broaching.
Virtually any type of prosthesis can be used with the anterolateral approach. Because of retraction of the abductors with this approach, some patients can have a limp lasting for 3-4 weeks and a longer period to regain abduction strength. This approach results in a stable hip, superior limb-length symmetry, and is considered versatile across a wide range of implant choices.