Direct Anterior Approach to Total Hip Replacement
Written by: Joseph R. Locker, M.D.
The Anterior Approach is an alternative to traditional hip replacement in which the hip is accessed from the front of the joint. A standard 10cm (4in) incision is made in the front (anterior) of the hip as opposed to the back (posterior) or side (lateral). The technique uses an interval between the muscles in order to limit injury to them during the course of the surgery. Leaving these muscles intact can limit the risk of dislocation after surgery, and may allow an accelerated recovery. Since the incision is in front, you’ll avoid the pain of sitting on the incision site.
The Anterior Approach is typically made possible with the use of a high-tech operating table that places the leg and pelvis in a stable position. This specially engineered table includes leg supports that allow the surgeon to adjust the operative leg during surgery with a great degree of control and precision. This table is designed to help achieve excellent alignment and positioning of the implant. Rather than being positioned on their side or stomach, the patient is laid flat on his/her back, which minimizes tilting of the pelvis during the operation. The table also gives excellent access to the femur, or thighbone, in order to position the stem of the implant effectively.
The procedure itself begins with exposing the hip in a way that does not detach muscles or tendons from the bone – a key attribute of the Anterior Approach. The diseased portion of the acetabulum is removed and replaced with a titanium cup. The surgeon then uses the specially designed table to rotate the operative leg so the foot points outward, extending toward the floor. This allows excellent access to the thigh bone, or femur, so the surgeon can replace the diseased portion of the bone with the stem implant. This is important since visibility is often limited due to smaller incisions.
Side-by-side TV screens are used to provide X-ray views of the operative hip and the patient’s opposite hip. This comparison gives information used to determine the desired position for an effective, stable hip replacement implant. The combination of this X-ray imaging and the high-tech table allows the doctor to seek precise control over the patient’s leg length as well.
The incision length, typically smaller than with standard surgery, varies according to a patient’s size, weight and other factors. The Anterior Approach lends itself to a relatively small incision because the hip joint is closest to the skin at the front of the hip. The muscle and fat layers are thinner than the muscle and fat tissue encountered when using other approaches on the side or rear of the thigh. While the smaller scar is a cosmetic advantage, surgeons say the actual size of the incision for each patient varies.
Another way that the Anterior Approach differs from some other techniques is with patient selection. Other minimally invasive techniques place more restrictions on patient selection. With other procedures, patients may need to be at their ideal bodyweight, for example. The Anterior Approach may make minimally invasive hip surgery possible for a wider range of patients, including larger, heavier patients. That’s because the Anterior Approach enters the body closer to the hip joint, with far less tissue between the skin and the bones of the hip, so more patients may be candidates.
Your doctor will tell you what restrictions you will have after surgery, and every surgeon has his or her own set of precautions for you to follow. Some surgeons who use the Anterior Approach place fewer restrictions in the days after surgery because the operation cuts no muscles around the hip, allowing patients to get back to activities of daily living with fewer limitations. I place no restrictions regarding positioning of the leg after surgery.
Although the Anterior Approach has been gaining popularity due to its numerous potential benefits, it is still not widely used by U.S. surgeons and accounts for less than 5% of all total hip replacements. I have been doing the anterior approach for hip replacement surgery since 2005 and am very satisfied with the results my patients have achieved.
Total hip replacement is considered the gold standard for hip arthritis and greatly improves the quality of one’s life. The Anterior Approach in one form or another has been around for many years. It can be performed safely and reproducibly with the use of the fracture table. More and more surgeons are learning this technique, and I believe it will continue to become more widespread as more long term studies are published. However, ultimately it is a decision between the patient and his surgeon to determine what surgical approach may be best for them.