The direct anterior approach (DAA) provides access to the hip joint through an intramuscular, internervous interval without abductor disruption.

Originally described by Smith-Peterson in the 1940s and later modified by Heuter in the 1950s, this approach has gained popularity recently by arthroplasty surgeons and may lead to earlier restoration of gait kinematics and have a lower dislocation rate.

Fluoroscopy is easily used in conjunction with this approach, and it can be performed with the patient supine with the leg free on a standard operating room table or on a specialty table.

Supine positioning places the pelvis in a neutral position, facilitates correct acetabular cup placement, and allows more accurate intraoperative assessment of leg length and stability.

Femoral exposure and access is more limited than for other anterolateral and posterior approaches. This limits the type of femoral components that can be used easily with this approach. Some studies have reported higher rates of femoral component loosening and femoral fracture with the DAA.

The lateral femoral cutaneous nerve may be injured in this approach, and this can bother patients.

Obese patient

The patient is positioned in the supine position either on a specialized traction table (Figure 4.1A and B) or on a standard operating table. It is important to ensure proper padding on the perineal post and around the traction boots if utilized. A 10- to 12-cm incision is made 2 cm distal and 2 cm lateral to the ASIS, centered over tensor fascia latae (TFL) muscle belly (Figure 4.2). This is usually about 15° off of a line subtended from the ASIS to the patella. The incision may be extended at either end for additional exposure. Extending the incision proximally and releasing the anterior 1 cm of TFL may aid in femoral exposure.

Superficial dissection is continued through the subcutaneous adipose tissue. If the lateral femoral cutaneous nerve or branches are encountered, protect and retract them medially. The fascia overlying the TFL is encountered. The purple hue of the TFL muscle belly should be noted (Figure 4.3). If this is not appreciated, it is likely that the approach has been made too medially. Once the TFL is properly identified, incise the fascia over TFL and develop the medial plane inside of fascia, over the TFL muscle belly (Figure 4.4).

A finger can then drop superior to the femoral neck, medial to the TFL muscle belly. An Ava-type retractor is then placed superior to the neck. A Meyerding retractor then retracts the TFL laterally (Figure 4.5). A sharp Hohmann retractor retracts the rectus muscle off of the inferior neck. The lateral femoral circumflex vessel branches are identified and coagulated. The deep layer of the TFL fascia and investing fat over the anterior femoral neck may be excised. An Ava retractor can then be placed inferior to the neck. The capsulotomy is then made in line with the anterior superior femoral neck. It is then continued in line with the intertrochanteric line, with the surgeon paying attention not to leave a cuff of capsule that would otherwise need to be removed for proper releases (Figure 4.6). This inferior limb of the capsulotomy may then be tagged with a #5 Ethibond suture to allow for identification and retraction during acetabular preparation. The Ava retractors may then be placed inside of the capsule superior and inferior to the femoral neck.