Direct Anterior Approach to Hip: Surgical Steps
The direct anterior approach (DAA) to the hip utilizes a true internervous and intermuscular plane between the tensor fasciae latae and sartorius muscles, providing direct access to the hip joint through a series of well-defined surgical steps. 1
Patient Positioning and Setup
- Position the patient supine on a standard orthopaedic table with a bump placed beneath the pelvis 1
- Add an additional arm-board to support the contralateral leg 1
- The procedure can be performed on a regular table with standard arthroplasty instruments, though some surgeons prefer specialized fracture tables with fluoroscopy capability 2, 3
- Proper limb positioning is critical to reducing intraoperative complications 2
Skin Incision and Superficial Dissection
- Make a longitudinal skin incision starting 3 cm lateral and distal to the anterior superior iliac spine 1
- Continue the incision distally along the tensor fasciae latae muscle 1
- Alternative technique: A curved transverse skin incision may be used 4
Intermuscular Portal Creation
- Create the intermuscular interval by making a longitudinal incision between the tensor fasciae latae (laterally) and sartorius (medially) muscles 1
- Split the tensor fasciae latae muscle longitudinally 4
- Perform blunt dissection medial to the tensor fasciae latae to develop this natural plane 1
- This approach preserves the innervation as it follows an intra-nervous interval 2, 3
Deep Exposure and Vascular Management
- Cauterize or ligate the ascending branches of the lateral circumflex artery, which are encountered during deep dissection 1
- Remove the precapsular fat pad to expose the underlying hip capsule 1
- This step is critical for adequate visualization and hemostasis 1
Capsulotomy and Femoral Neck Osteotomy
- Perform an anterior capsulectomy by incising the capsule longitudinally along the femoral neck 1
- Make a perpendicular incision at the capsule's attachment to the neck 1
- Excise the anterior portion of the capsule 1
- Perform a double osteotomy: one at the subcapital level and another at the base of the femoral neck 1
- This provides adequate exposure while preserving posterior capsular structures 1
Acetabular Preparation
- Incise the medial portion of the capsule to fully expose the acetabulum 1
- Remove the labrum and any osteophytes 1
- Use standard or offset reamers to prepare the acetabulum 1
- Excellent visualization of the acetabulum is a key advantage of this direct approach 4
- Implant the acetabular cup according to standard anatomical landmarks 1
- Fluoroscopy may be used intraoperatively for component positioning verification, particularly beneficial during the learning curve 2
Proximal Femoral Release
- Remove the superolateral aspect of the capsule 1
- Release the posterior capsular attachments to allow femoral elevation 1
- This step is essential for adequate femoral exposure without excessive soft tissue trauma 1
Femoral Preparation and Implantation
- Open the femoral canal with the leg positioned in external rotation 1, 4
- Use modified femoral rasps of varying lengths, specifically double offset broachers designed for this approach 1
- Broach the femur progressively to create the appropriate space 1
- Insert the femoral component into the prepared canal 1
- The external rotation positioning allows adequate visualization without requiring trochanteric osteotomy in most cases 4
Key Technical Considerations
- The procedure can be extended proximally or distally if needed for complex primary or revision cases 1
- Trochanteric osteotomy is rarely required (only 3 of 104 procedures in one series) 4
- Average operative time is approximately 65 minutes for unilateral procedures 4
- Proper patient and limb positioning management is vital to reducing intraoperative complications 2