Alignment and positioning of implants is important in total knee arthroplasty (TKA). Identifying the femoral hip center (FHC) without fluoroscopy or computer navigation is considered difficult. The Complete Compass system (CoCo) is a femoral extramedullary guidance system designed to identify the FHC. This apparatus provides an accurate representation of the femoral functional axis in the coronal plane without a computer navigation system. We compared postoperative implant alignment of patients undergoing total knee arthroplasty between CoCo and intraoperative computer navigation. Twenty-five consecutive TKAs using CoCo were analyzed. CoCo has a pivotal arm with a pivotal shaft arranged to extend perpendicular to the coronal plane. A marker is attached to the pivotal arm to depict a circular arc on the marking plate with rotation of the pivotal arm. The pivotal shaft is placed at the intercondylar notch of the femur. The distance from the pivotal shaft to the marker is equal to the distance from the intercondylar notch of the femur to the FHC of the patient based on preoperative measurements in the coronal plane. This apparatus has a level of the horizontal plane and the condition of the pivotal shaft is able to match neutral positions in the sagittal and axial planes. The intersection of two arcs drawn by using CoCo with the hip joint in abduction and adduction indicates the FHC position. Postoperative coronal and sagittal views radiographs were obtained. Twenty-five TKAs implanted using computer navigation were also analyzed for postoperative alignment. For two groups, targeted implant position was 90° in both planes for the femoral functional axis.Introduction
Materials and Methods
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. 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.Introduction
Material and Method
