The surgeon using the DAA should be aware of potential challenges that might be encountered, including the risk of proximal femur fracture and wound healing problems.¹ Masonis et al² reported that the DAA for THA can be performed safely and efficiently with adequate training; however, there may be a steep learning curve. Although not required, use of the radiolucent Hana table (Mizuho OSI) greatly facilitates femoral exposure by essentially functioning as a surgical assistant. The table allows for ease of extremity manipulation and greater control over positioning. An elevating hook can be placed on a sterile attachment bracket mounted to the table that aids in exposing the proximal femur. Additionally, the table allows the surgeon to use intraoperative fluoroscopy as well as provide facile access for simultaneous bilateral THA. Herein we describe the essential surgical technique of performing DAA THA with the use of the Hana table as originally described by Matta et al³ with modifications by the senior author (SK) that continue presently.

The DAA to the hip is routinely performed with the patient in the supine position. At our institution, we use the Hana table. This table allows for safe hyperextension, external rotation, and adduction of the leg, which greatly facilitates optimal femoral exposure (Figure 10.1). The table is confirmed to be level before patient positioning. Typically, an intermediate-acting spinal anesthetic is administered; however, general anesthesia can also be used. A perineal post is placed to provide a counterforce while the operative extremity is manipulated during the procedure. The post should be well padded to reduce the risk of pudendal nerve palsy. The patient’s feet are sequentially placed into the Hana table boots and secured. Care should be taken to ensure that the patient’s heel is snug in the posterior aspect of the boot because suboptimal positioning may compromise limb security during the case. The operative extremity can be further secured to the boots by overwrapping them with Coban Self-Adherent Wrap (3M).

The legs are placed in neutral rotation and approximately 5° to 10° of hip flexion to minimize tension on the rectus muscle and anterior capsule. Alternatively, Matta et al³ described placing the legs in 15° of internal rotation to maximize visualization of the tensor fascia muscle as well as to optimize visualization of the femoral neck offset on fluoroscopy. Traction is unlocked at this time. If the patient has a large abdominal pannus, it should be taped and secured away from the surgical site. The patient is prepped from the umbilicus down to the distal thigh. The authors prefer to use ChloraPrep (BD). The operative field is squared off with towels from the superior brim of the iliac crest to the proximal aspect of the patella to facilitate an extensile approach if necessary. Ioban 2 antimicrobial incise drapes (3M) followed by a shower isolation curtain (Steri-Drape, 3M) are placed in a sterile fashion. The aforementioned steps can be reproduced on the opposite side to facilitate bilateral THA (Figure 10.2).

Landmarks for the DAA are the anterior superior iliac spine (ASIS), greater trochanter, and patella. In thin patients, palpation of the tensor fascia muscle substance is also helpful. The incision is started 1 cm distal and 3 cm lateral to the ASIS, aiming distally in line with the lateral aspect of the patella. The length of a standard incision should be approximately 7 to 8 cm; however, this can be modified depending on the size of the patient. In patients with a large abdominal pannus, the surgeon may elect to move the incision slightly more lateral or use a bikini incision, which has been shown to be safe with regard to implant positioning and nerve injuries⁴ and has lower rates of wound healing complications in obese patients.⁵ If appropriate, a bikini incision can be drawn out parallel and 1 cm distal to the inguinal fold, with the medial one-third directly inferior to the ASIS.

The skin and subcutaneous tissues are incised and sharply dissected until a thin layer of fascia over the tensor muscle is visualized. Excessive proximal blunt dissection of the subcutaneous tissues should be avoided because this causes unnecessary dead space and risk for wound complications. The fascial layer in this region is relatively thin and translucent, and the substance of the tensor muscle should be visible with a dark blue appearance (classic “bluish hue”; Figure 10.3). The iliotibial band lies posterior to this and is less translucent. A small stab incision is made over the fascia, which is then sharply divided with Mayo scissors to the ASIS proximally and 2 to 3 cm past the skin incision distally. The orientation of the tensor fascia muscle fibers should be in line with the skin incision. If the fibers are observed going in a vertical or obliquely medial orientation, the approach may be too far lateral (violating the gluteus medius) or medial (violating the sartorius), respectively. An Allis clamp is placed on the medial fascial flap. This flap is gently elevated, mobilizing the tensor muscle laterally, and the interval between the rectus and tensor is developed (Figure 10.4). A Cobb elevator may be used to elevate any muscle fibers that may be adherent to the fascia, ensuring an anatomic dissection. This plane is followed medially until encountering a layer of adipose tissue or “fat stripe” because the tensor fascia lata (TFL) sits within a “fascial pillow.” The interval between the superior femoral neck and the gluteus medius and minimus is developed bluntly proximally, whereas the remainder of the tensor is freed distally.

A sharp Cobra retractor is placed on the superior aspect of the femoral neck between the capsule and the gluteus medius and minimus. The reflected head of the rectus and iliocapsularis muscles are identified along the anterior capsule.⁶ These muscles, if prominent or contracted, may obscure visualization of the hip and may rarely require release. A Hibbs retractor is placed medially retracting the rectus, exposing a layer of innominate fascia (Figure 10.5). Electrocautery is used distally to dissect through this first layer of fascia between the rectus and the TFL. This will mobilize the rectus away from the tensor, unveiling a second deeper layer of fascia that is superficial to the vastus lateralis. Dividing this next layer will cause the belly of the vastus intermedius to enter the surgical field. The ascending branches of the lateral circumflex artery are now visualized and can be ligated with sutures, surgical clips, or adequate cautery (Figure 10.6). The authors prefer to use a tonsil clamp and electrocautery to divide these vessels. It is critical to obtain sufficient hemostasis of these vessels because they tend to bleed later in the case.

After appropriate dissection of the innominate fascia, a layer of pericapsular adipose tissue is encountered. Electrocautery is used to dissect this tissue off the capsule while the indirect head of the rectus is identified and preserved. A sharp Hohmann retractor is now placed on the superior rim of the acetabulum, allowing visualization of a “triangle” of capsule bordered by the rectus, indirect head, and vastus lateralis.

An inverted T-shaped capsulotomy is performed beginning at the lateral one-third of the femoral neck from the superior rim of the acetabulum to the intertrochanteric ridge inferiorly. Alternatively, a capsulectomy can be performed to facilitate the exposure. Avoid extending the capsulotomy distally into the muscle fibers of the vastus intermedius because perforating vessels can be encountered. The inverted “T” limbs of the capsulotomy are completed by incising the capsule medially toward the lesser trochanter and laterally toward the “saddle” of the proximal femur. The corners of the capsule are tagged with sutures for later repair (Figure 10.7). At this point, the authors prefer to place a flexible circular protractor Alexis Retractor (Applied Medical, Rancho Santa Margarita, CA, USA) under the TFL to protect it and the skin and subcutaneous tissues from unintentional injury during the procedure (Figure 10.8).

Both capsulotomy repair and capsulectomy are viable options. McLawhorn et al⁷ evaluated 32 patients who underwent DAA THA who underwent either capsulotomy repair or capsulectomy. Metal artifact reduction sequence magnetic resonance imaging at 1 year showed no capsular defect in patients who underwent capsulotomy repair, whereas 27% of patients who underwent capsulectomy had persistent defects. The authors prefer to preserve and repair the capsule, providing an additional layer of soft tissue between the prosthesis and deep fascia and recreating the natural anatomy.

Cobra retractors are now placed inside the capsule medially and laterally over the femoral neck and head. If the anterior capsule is significantly scarred, releasing the capsule off the anterior wall of the acetabulum can facilitate proper placement of the medial retractor. Alternatively, the tip of this retractor can be gently wedged into the femoral head, effectively putting the inferior and medial capsule under tension for release. Similarly, the lateral retractor will place tension on the superior and lateral capsule. A sequence of capsular releases is then performed for proper exposure of the femoral neck and head before osteotomy. The first release is performed superolaterally at the capsulolabral junction, starting superiorly at the anterior inferior iliac spine and working in an anterior to posterior direction (starting at 1 o’clock on a left hip and 11 o’clock on a right hip; Figure 10.9). Inadvertent release of the indirect head of the rectus tendon should be avoided. The second release is performed medially and inferiorly as the capsule is released off the intertrochanteric ridge coupled with progressive external rotation of the femur to aid in visualization. Forceful external rotation of the femur should be avoided because this may result in iatrogenic fracture.

Significant anterior osteophytes and/or an ossified anterior labrum should be removed before neck osteotomy to facilitate removal of the femoral head. The femur is rotated back to neutral, and an in situ cut of the femoral neck can be performed (Figure 10.10).

A transverse subcapital cut is performed first on the femoral neck. The femur is now externally rotated again to release any remaining inferior or medial capsule because the osteotomized femur will now allow for a greater arc of external rotation. The capsule is released until the lesser trochanter is readily visualized or palpated. Incomplete release of this portion of the capsule will tether the femur to the acetabulum and hinder femoral exposure later in the case. The leg is rotated back to neutral for the second neck cut. Visualization of the junction of the superior femoral neck and the medial greater trochanter, or the “saddle,” is essential to ensuring a proper final cut that coincides with preoperative templating. Anterior neck osteophytes should be removed because they may obscure visualization of the saddle and create a lower-than-anticipated resection.

The saw blade is angled posteromedially in preparation for the second neck cut. A Hohmann retractor is placed along the medial aspect of the greater trochanter to protect it during the osteotomy and avoid iatrogenic injury (Figure 10.11). Avoid plunging with the saw because perforating branches of the medial circumflex artery can be damaged and cause significant bleeding. Once completed, a “napkin ring” of bone from the femoral neck is removed with a Kocher or rongeur while gentle traction is applied to the leg (Figure 10.12). A corkscrew is then advanced centrally into the femoral head (Figure 10.13). Superior and medial skids can be used to help dislocate and remove the head. Usually, the force generated from placing the corkscrew on power is enough to disrupt the ligamentum teres, causing the femoral head to spin freely and facilitate extraction (Figure 10.14).