Abstract
Introduction
Total hip arthroplasty (THA) using the direct anterior approach (DAA) in a supine position is a minimally invasive surgery that reduces postoperative dislocation. Excellent exposure of both the acetabulum and proximal femoral part is important to reduce intraoperative complications. Generally, two surgical assistants need to hold four retractors to maintain excellent exposure of the acetabulum. We examined intra- and postoperative complications as indicators of the efficiency of using the “Magic Tower” (MT) device compared with a non-MT group.
Material and Method
Twenty consecutive DAA THAs using MT were analyzed, and 20 DAA THAs not using MT were also analyzed. MT is a retractor-holding device, and has an arm structure that can be moved in a wide variety of directions. This device holds a retractor stably, and each movement of the arm can be locked by one click. Operating time, blood loss, length of skin incision, intraoperative complications, and number of assistants were recorded. Postoperative radiographs were obtained to evaluate implant position.
Results
Mean operating time was 105 min in the MT group and 118 min in the non-MT group. Mean blood loss was 232 g in the MT group and 233 g in the non-MT group. Mean length of skin incision was 80 mm in the MT group and 85 mm in the non-MT group. Mean cup inclination was 45.8° in the MT group and 47.3° in the non-MT group. Postoperative implant position was also excellent in both groups. In all comparisons, no significant differences were seen between groups. No intraoperative complications were encountered. Two assistants were required in the non-MT group, and one in the MT group.
Discussion
A majority of the complications reported with THA can be attributed to access issues, i.e., difficulties in exposure and accurate component implantation. To achieve excellent exposure at the acetabulum, four retractors (anterior, posterior, cranial, and caudal) are desirable. In such procedures, two surgical assistants are needed to hold retractors. One of these assistants needs to hold the anterior retractor and cranial/caudal retractor from the opposite side of the surgery beyond the abdomen of the patient. However, the assistant on the opposite side cannot achieve good exposure, as strong retraction of the anterior part of the acetabulum may cause complications of femoral nerve palsy. The MT is able to hold a retractor firmly by applying pressure toward the acetabulum instead of traction, and also reduces the number of surgical assistants required. While preparing the femur, exposure of the femoral canal was also better than in the non-MT group.
Conclusion
In primary DAA THA, no significant differences between groups were identified. However, the MT is clearly a useful device that allows maintenance of excellent exposure, reducing the number of surgical assistants required.
