Reverse an electric operating room table so that the distal segment can be dropped to a 40° angle when it is time to broach the femur. Attach an arm-board to the contralateral side of the table so that the contralateral leg can be moved into abduction when the femur is prepared on the surgical side.

Place the patient supine on the operating table with a 2-in (5-cm) foam pad or folded blankets under the sacrum. This allows the gluteal fat pad to hang posteriorly during the procedure. Position the patient so that the later table drop will be at the level of the patient's greater trochanter and the surgical side is flush with the edge of the bed to allow maximum room for positioning during femoral preparation (Fig. 1).

Prepare the operative leg, leaving the contralateral leg free to be positioned under the drapes by an assistant (Fig. 2). This will be important during femoral preparation.

Identify and mark the anterior superior iliac spine and the greater trochanter. Mark the top of the incision by making a point three fingerbreadths posterior to the anterior superior iliac spine. Draw the incision straight down the leg past the greater trochanter (Fig. 3). The usual incision length is 8 to 10 cm.

After making the skin incision, identify the fascia overlying the tensor fasciae latae. You will usually be able to see the muscle belly and perforating vessels posteriorly through the fascia.

Make an incision in the fascia in line with the skin incision (Fig. 4). Bluntly lift up the anterior edge of this fascia (Fig. 5).

Bluntly develop the interval between the sartorius and the tensor fasciae latae and place deeper retractors between these muscle bellies. The lateral circumflex vessels are seen running lateral and perpendicular to the rectus femoris muscle. These vessels must be identified and ligated before proceeding deeper (Fig. 6).

Enter the deep interval along the side of the rectus femoris proximal to the greater trochanter. Curve this deep approach medially away from the anterior insertion of the abductor musculature onto the greater trochanter. Place a pointed Hohmann retractor inside the abductor musculature to rest on the superior aspect of the hip capsule between the greater trochanter and the superior aspect of the femoral neck. Lift up the knee, flexing the hip approximately 30° (Fig. 7); this will allow placement of a blunt Hohmann retractor against the medial aspect of the femoral neck (Fig. 8).

Release the reflected head of the rectus femoris from the anterior aspect of the acetabulum (Fig. 9). After this release, place a wide pointed Hohmann retractor perpendicular to the inguinal ligament at the level of the released reflected head of the rectus femoris. Now place the knee flat on the table.

Make a capsular incision from the intertrochanteric line to the anterior rim of the acetabulum (Fig. 10). Remove the superior portion of the capsule and expose the superior aspect of the femoral neck and the medial aspect of the greater trochanter (“the saddle”). Either excise or tag the inferior piece of capsule with sutures (Fig. 11).

Replace the superior and inferior Hohmann retractors adjacent to the capsule. Make an osteotomy at the base of the femoral neck at the level of the so-called saddle at the base of the greater trochanter (Fig. 12). Make a second cut more proximally, at the level of the femoral head-neck junction (Fig. 13). Remove both osseous pieces with a 4.0-mm Schanz pin or a corkscrew device (Fig. 14).

Place the superior and inferior acetabular retractors at the six o'clock position (the transverse acetabular ligament) and nine o'clock position in front of the transverse acetabular ligament. Keep the wide Hohmann retractor in the same place anteriorly. Remove any osteophytes, labrum, and foveal tissue. Make two or three “pie-crust” incisions in the posterior aspect of the capsule to increase mobility. Resect more of the femoral neck until the fold of the posterior aspect of the capsule is seen.

Ream the acetabulum in 10° to 15° of anteversion with an abduction angle of 40° to 45° (Fig. 15). After reaming, insert the acetabular component and liner (Fig. 16).

Remove all retractors and place the leg in a “figure of four” position. Release the medial aspect of the capsule until you can visualize the lesser trochanter. Place the leg back on the table flat and remove any remaining superior capsular tissue. Using a bone hook, pull up on the femur to assess the ability of the femoral neck to be brought up and away from the acetabulum. Release the superior aspect of the capsule and the piriformis tendon to facilitate exposure.

With the femur mobilized, drop the end of the table 40° and adduct the operative leg with external rotation. The contralateral leg is placed on the arm-board in abduction.

Place retractors to hold the femur in place and protect the soft tissues (Fig. 17). Open the femoral canal with offset reamers, rasps, and curets (Fig. 18). Use offset broaches to access the femur and prevent perforation through the greater trochanter (Fig. 19).

Insert the femoral component.

Evaluate the implant stability and leg lengths (Fig. 20). Specifically check for impingement of bone on the implant with flexion of the hip to 90° (Fig. 21). Check anterior stability with extension and external rotation. After satisfactory component placement is confirmed, close the wound in layers (Figs. 22 and 23).

Use an abduction or standard pillow until the patient is fully awake and then remove it.

Most patients can be treated with the direct anterior approach for placement of a total hip prosthesis.

Typically, this technique is the most straightforward in female patients with a supple hip and few osteophytes.

Hips with a low greater trochanter are typically easier to treat with this technique than hips with high offset.

An extensile exposure can be utilized with this approach. The incision can be extended down the femur in either the Smith-Petersen or Watson-Jones interval (anterior or posterior to the tensor fasciae latae) for fractures or revisions. The tensor fasciae latae may also be partially released from its proximal origin to increase femoral exposure.

Infection, sepsis, and osteomyelitis

An uncooperative patient

Neurological and cognitive disorders that prevent the patient from following instructions

Vascular or neuromuscular disorders that preclude the patient from walking

Take care to avoid any mechanical or pneumatic device to “pull up” the femur since this can lead to fractures of the greater trochanter. The retractors should “hold up” the femur after an adequate soft-tissue release has been performed.

Femoral exposure can be difficult without a proper soft-tissue release. Generous excision of the superior aspect of the capsule facilitates exposure. Similarly, it may be necessary to release the piriformis tendon to increase exposure. Take care to ligate the vessels adjacent to the piriformis tendon when performing this procedure.

Straight femoral stems should be avoided. Curved offset instruments are necessary to ensure proper placement of the femoral components. The best component is a curved stem with a “cut-down” greater trochanteric shoulder.

Avoid overreaming of the anterior acetabular wall. It is best to use a smaller reamer first to encourage the proper anteversion before using a normal-size reamer.

Avoid excessive acetabular cup anteversion. It is best to remove all posterior osteophytes as this will allow more precise implantation of the cup and also help mobilize the femur into the wound.

What measures do you take to mobilize the femur with the direct anterior approach to prevent femoral fractures?

What restrictions, if any, do you place on patients postoperatively?