Direct Anterior Approach to the Hip (Hueter Interval)

What it exposes. The direct anterior approach (DAA) gives direct access to the anterior hip capsule, the femoral head and neck, and the acetabulum through the Hueter interval. It is the workhorse exposure for primary total hip arthroplasty and also serves hip hemiarthroplasty for femoral neck fracture, femoral head and neck work (fracture fixation, cam-type femoroacetabular impingement osteochondroplasty, femoral head resurfacing), hip preservation (combined with a proximal extension for periacetabular osteotomy and open reduction of developmental dysplasia), septic arthritis drainage, synovial or femoral head and neck biopsy, and removal of femoral head and neck tumours within the reach of the exposure. Why this approach is chosen. The DAA reaches the hip through the Hueter interval, a true internervous plane between muscles supplied by the femoral nerve medially and the superior gluteal nerve laterally. Because no muscle or tendon is detached, it is genuinely muscle-sparing, which underpins faster early recovery, a low dislocation rate and accurate supine fluoroscopic control of component position, leg length and offset. Contraindications and relative cautions. - Revision arthroplasty with major bone loss or stem removal — a trochanteric-slide or extended approach is usually required

• Complex acetabular reconstruction needing posterior or extensile exposure
• Severe obesity with a large pannus — wound problems and deep retraction are more difficult, although the supine position is often better tolerated than the lateral
• Previous anterior hip surgery with compromised soft tissues
• Surgeon inexperience — the learning curve is real and early complications rise during it
• A very muscular or large male femur, where femoral delivery and broaching are harder Alternative approaches. - Posterior (Moore/Southern): the most extensile, excellent femoral exposure, but detaches the short external rotators and has a historically higher dislocation rate
• Anterolateral (Hardinge / transgluteal): splits gluteus medius, good exposure, partial abductor damage
• Lateral (Hardinge variants): reliable exposure, abductor-splitting
• Smith-Petersen (iliofemoral): the extended anterior parent approach, used for periacetabular osteotomy and acetabular column work Position & landmarks. The patient is supine on a radiolucent table so that a true anteroposterior fluoroscopic view of the acetabulum is obtained. Two setups are in common use, and both keep the patient supine: - Specialised orthopaedic traction table (the classic Judet/Matta setup): the foot is secured in a boot, the leg is controlled for traction, flexion, adduction and external rotation, and the pelvis is stabilised — reproducible and stable, but commits the surgeon to the table
• Standard radiolucent table with the leg free: the leg is left unsecured and moved by an assistant or leg positioner — increasingly popular, avoids the dedicated table, but femoral exposure depends on skilled assistance and the right retractors Confirm a radiolucent table and obtain a baseline fluoroscopic AP before draping; keep the pelvis stable and square (no tilt); palpate and expose both iliac crests and the ASIS; bring the C-arm in from the contralateral side; pad all pressure points and secure the arm on the contralateral side. With the leg free, guard against the pelvis rolling when the leg is placed in extension and external rotation for femoral work. The key bony landmarks are the anterior superior iliac spine (ASIS) — the critical reference, with the incision based lateral and distal to it; the greater trochanter — marks the lateral extent; the iliac crest — defines the Smith-Petersen extension line; and the pubic tubercle — medial reference, with the femoral vessels and nerve just lateral to it under the inguinal ligament. For incision planning, draw a line from the ASIS to the tip of the greater trochanter; start the skin incision about 2 cm lateral and 1 to 2 cm distal to the ASIS and run obliquely along this line for about 8 to 10 cm, overlying the tensor fasciae latae. Staying lateral to the ASIS is deliberate — it protects the LFCN, which courses close to the ASIS on its medial side.

Work down through the layers over the tensor fasciae latae, developing the Hueter internervous interval to the capsule. The defining feature of the approach is that it is a true internervous plane: superficially the dissection passes between sartorius and rectus femoris (femoral nerve) medially and tensor fasciae latae (superior gluteal nerve) laterally, and the deep interval is then opened between rectus femoris medially and gluteus medius and minimus laterally to reach the capsule — so no muscle is denervated.

Structures at risk, by layer

Extensile options. Extend proximally along the iliac crest to become the Smith-Petersen (iliofemoral) approach: carry the incision back along the crest, strip the abdominal muscles and the origin of gluteus medius and minimus subperiosteally off the outer table of the ilium, and detach sartorius and the inguinal ligament from the ASIS for still wider medial exposure. This gives broad access for periacetabular osteotomy, open reduction of developmental hip dysplasia, anterior column acetabular fractures and iliac tumour resection. Extend distally onto the proximal femoral shaft between rectus femoris (medially) and vastus lateralis (laterally) for diaphyseal work, watching for the descending branch of the lateral circumflex femoral artery and the nerve to vastus lateralis, which cross this more distal interval. When to convert. If exposure proves inadequate — a large muscular femur, unexpected anatomy, or the need for stem extraction in revision — do not persist blindly. Convert to a trochanteric osteotomy or an alternative approach rather than risk a calcar fracture, femoral perforation or abductor damage. Closure. Irrigate copiously and achieve meticulous haemostasis, paying particular attention to the divided ascending branch of the lateral circumflex femoral artery. Repair the capsule with absorbable or non-absorbable sutures — this restores the anterior soft-tissue envelope and contributes to a low dislocation rate. Close the TFL fascia meticulously with absorbable suture (this layer is important for restoring the muscle corridor), approximate the subcutaneous layer, and close the skin with a subcuticular suture or staples. Confirm component position, leg length and offset on a final fluoroscopic AP and on a formal postoperative radiograph, documenting the orientation of the acetabular and femoral components.

• Total hip replacement via the direct anterior approach — the dominant modern operation done through this exposure.
• Hip hemiarthroplasty for femoral neck fracture in a suitable patient.
• Femoral head and neck work — femoral neck fracture fixation, cam-type femoroacetabular impingement osteochondroplasty, and femoral head resurfacing.
• Hip preservation surgery — combined with the proximal Smith-Petersen extension for periacetabular osteotomy and open reduction of developmental dysplasia.
• Septic arthritis drainage and synovial or femoral head and neck biopsy.
• Removal of femoral head and neck tumours within the reach of the exposure.

Guidelines, registries & global practice. The direct anterior approach is practised worldwide and its principles converge across examination systems. It is a muscle-sparing, internervous exposure performed supine, increasingly used for primary total hip arthroplasty and for anterior hip preservation work.

Global practice variation. High-volume centres worldwide use both traction-table and standard-table techniques. In some regions the posterior approach remains the default for primary THA, while the direct anterior approach dominates in others. The shared, examinable constants are the internervous plane, the supine position, protection of the lateral femoral cutaneous nerve, ligation of the ascending branch of the lateral circumflex femoral artery and the technique of femoral delivery. Consent (globally applicable). Discuss lateral femoral cutaneous nerve injury with anterolateral thigh numbness (often transient), intraoperative femoral fracture (notably calcar or trochanter, more frequent during the learning curve), wound complications (more common in obesity), leg-length discrepancy, dislocation, infection, thromboembolism, and the need for revision.