9: Direct Anterior Approach With Modular Table Attachment and Traction Boot
Amir Pourmoghaddam
Adam M. Freedhand
Roy I. Davidovitch
Stefan W. Kreuzer
Key Learning Points
How to properly position the ARCH (Innovative Orthopedic Technologies), PURIST (Innovative Orthopedic Technologies), and RotexTable (Condor MedTec) tables for direct anterior approach (DAA) total hip arthroplasty (THA) surgery.
How to identify the key functions of the ARCH, PURIST, and RotexTable tables.
How to apply the functions of the ARCH, PURIST, and RotexTable table extensions to the appropriate steps of DAA THA.
Introduction
The DAA is a classic surgical approach; since its description by Carl Hueter over a century ago, it was used for THA only sporadically until the last few decades. 1 , 2 The interest in DAA THA has been driven by its muscle-sparing technique, which supports less invasive surgery, 3 and the supine position allows the surgeon to assess the pelvic position more easily. The supine position also facilitates the use of intraoperative radiography or fluoroscopy to assess component position. Proponents of special tables or leg positioning systems cite their ease of use, the need for fewer assistants, and higher reliability in surgical outcome. 4 , 5 The orthopaedic traction systems have become important tools during DAA THA because they facilitate proper exposure of the femur to reduce the chance of malpositioning of the femoral components. 6 The ARCH and PURIST Leg Positioning Systems are designed to be used with standard operating room (OR) tables to maintain and control the leg position during DAA surgery (Figures 9.1 and 9.2).
 Figure 9.1 The ARCH table attachment. (Reprinted with permission from Innovative Orthopedic Technologies LLC.) |
 Figure 9.2 The PURIST system. (Reprinted with permission from Innovative Orthopedic Technologies LLC.) |
Component position affects the longevity and performance of THA. 7 Malpositioning and soft tissue imbalance can lead to dislocation risk, impingement, accelerated polyethylene wear, and early revision surgery. 8 , 9 Numerous studies have described the ideal acetabular position, but few have addressed the variability and dynamic nature of the true pelvic orientation unique to each patient. 10-12 Intraoperative patient positioning affects the ability to accurately estimate pelvic tilt and rotation.
ARCH Table
The ARCH system (see Figure 9.1) is a freestanding attachment for a standard operating table that was designed for leg positioning during DAA THA. It can also be used during other orthopaedic procedures (ie, hip arthroscopy, hip fractures, and femoral neck open reduction internal fixation). This table attachment is draped outside of the sterile field and can be controlled by an assistant (Figure 9.3). The ARCH extension allows for measured leg rotation, extension, flexion, adduction, and abduction. Movements are calibrated in degrees and allow for reproducible leg positioning during DAA surgery. The table also allows for traction to be measured in centimeters. The table extension is amenable to intraoperative fluoroscopy with a portable C-arm intensifier unit (Figure 9.4).
 Figure 9.3 The ARCH leg position device used during surgery. (Reprinted with permission from Innovative Orthopedic Technologies LLC.) |
 Figure 9.4 The intraoperative view of the full pelvis. (Reprinted with permission from Innovative Orthopedic Technologies LLC.) |
Surgical Technique
Specific steps for the safe use of the ARCH extension system include the following:
 Figure 9.5 The MP XRAYCER system. (Reprinted with permission from Innovative Orthopedic Technologies LLC.) |
Patient positioning and draping: Patients are positioned supine on a standard OR table. The operative leg is secured inside the ARCH device, and the contralateral leg is placed in a well-leg holder. The well-leg holders include a peroneal post incorporated into a radiography cassette holder. The ARCH should be positioned approximately 52 in (matching its radius) from the center of rotation of the hip to minimize unintentional traction or compression of the leg with changes in position. The leg should be in a neutral anatomic position (see Figure 9.4).
Surgical exposure: During the approach to the hip, the leg is held in a neutral position without any traction. Capsular exposure and the surgical release of the medial capsule from the femoral calcar can be facilitated with external rotation of the leg to deliver the lesser trochanter toward the surgeon. Specific capsular releases are dependent on surgeon preference; however, fewer releases may be necessary when using a leg-holding device.
Neck osteotomy and femoral head extraction: The femoral neck osteotomy is made with the foot in the neutral position and should be made with a single or double osteotomy perpendicular to the femoral neck. After completion of the osteotomy, approximately 40 mm of traction and 40° of external rotation (the 40/40 position) is applied to displace the osteotomy and gain access to the head fragment. The femoral head is then extracted with a corkscrew device, taking care to protect the surrounding muscles from any sharp bone edges.
Acetabular exposure: Deep retractors are placed on the acetabular rim while maintaining the 40/40 position with the ARCH device. Mild traction can be applied during acetabular reconstruction to facilitate exposure. After acetabular preparation and implantation of the socket, traction is released and the leg is brought back to the neutral position.
Femoral exposure: Capsular releases are begun with the leg in the neutral position without traction. Slight traction needs to be applied before external rotation to allow the greater trochanter to clear the lateral margin of the acetabulum before leg positioning for femoral preparation. After additional capsular releases as needed, a combination of further external rotation, extension, and adduction of the leg allows access to the proximal femur. The edge of the OR table of the bump of the MP XRAYCER (Innovative Orthopedic Technologies) deck helps elevate the femur into the
surgical field to facilitate femoral broaching. The MP XRAYCER system is used as a tabletop accessory that allows better access to the surgical site (Figure 9.5). In addition, this accessory facilitates taking a full pelvic radiograph during DAA THA by allowing radiography cassettes to be used with standard OR tables. Sequential and appropriate capsular releases must be performed to reduce stresses on the proximal femur before stem preparation; these steps are addressed elsewhere in this text.Related posts:
2: A Definitive History of the Direct Anterior Approach
4: Surgical Anatomy of the Anterior Hip and Thigh
6: Direct Anterior Approach for Hip Replacement: The Learning Curve
7: Training and Education for the Direct Anterior Approach
11: Direct Anterior Approach in the Lateral Decubitus Position
10: Direct Anterior Approach With the Mizuho OSI Hana Table
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