In total hip arthroplasty (THA), the importance of preserving muscles is widely recognized; therefore, muscle-sparing approaches are widely used. Recently, we reported that there are bony impressions, that we called the obturator attachment (OA), on the greater trochanter that indicate the insertions of the short external rotator tendons. In this study, we used a three-dimensional (3-D) template to evaluate damage to the insertions of the short external rotator muscles during a femoral procedure. We investigated 12 hips in 10 patients who underwent THA. Preoperative CT imaging of the hip was performed, and 3-D reconstruction of the greater trochanter was used to visualize the bony impressions that indicate the insertions of the obturator internus and externus muscles (Fig 1A). We performed preoperative 3-D templating of two different femoral prosthesis (flat tapered-wedge stem: J-Taper, cylindrical straight stem: PerFix910) and then evaluated the extent of damage to the OA during the stem placement (Fig 1B, 1C). The extent of damage to the OA was classified using the following scale: grade 0, no damage of the insertion area; grade 1, less than 1/3; grade 2, equal to or more than 1/3–2/3; grade 3, equal to or more than 2/3; grade 4, complete.Background
Methods
The patterns and magnitudes of axial femorotibial rotation are variable due to the prosthesis design, ligamentous balancing, and surgical procedures. LCS mobile-bearing TKA has been reported the good clinical results, however, knee kinematics has not been fully understood. Therefore, we aimed to investigate the effects of the weight-bearing (WB) condition on the kinematics of mobile-bearing total knee arthroplasty (TKA). We examined 12 patients (19 knees) implanted with a low contact stress (LCS) mobile-bearing TKA system using a two- to three-dimensional registration technique as previously reported [1]. All 12 patients were diagnosed with medial knee osteoarthritis. The in vivo kinematics of dynamic deep knee flexion under WB and non-WB (NWB) conditions were compared. We evaluated the knee range of motion, femoral axial rotation relative to the tibial component, anteroposterior translation, and kinematic pathway of the femorotibial contact point for both the medial and lateral sides.Background
Methods
In total hip arthroplasty (THA), preservation of the short external rotator muscles are considered to be important because they contribute to joint stability and prevent postoperative dislocation. Recently, we reported that there are bony impressions on the greater trochanter that indicate the insertions of the short external rotator tendons. In this study, we reported a method to visualize the bony impressions using preoperative CT images, and evaluate the reliability and accuracy of this method. Thirty-three hips from 24 consecutive patients undergoing THA were enrolled. The mean age was 65.3 years. Preoperative diagnoses included hip osteoarthritis in 27 hips, rheumatoid arthritis in 4 hips, idiopathic osteonecrosis in 1 hip, femoral neck fracture in 1 hip. Preoperative CT of the hip region was obtained and three-dimensional (3D) reconstruction of the greater trochanter was performed to visualize the bony impressions, that we called the obturator tendon attachment (OTA), indicating the attachment area of the obturator internus and externus muscles.Background
Methods
The lateral radiographs are useful in evaluation of the acetabular cup anteversion. However, this method was affected by variations in pelvic position and radiographic technique. In this study, we employed the ischial axis (IA) as an anatomical landmark on the lateral radiographs, and we investigated a relationship between IA and the anterior pelvic plane (APP) using three-dimensional computed tomography (3D-CT). Using these findings, we report a new method for accurate measurement of the acetabular cup anteversion on plain lateral radiographs using IA as an anatomical reference. At first, preoperative3D-CT images were obtained in 109 patients who underwent total hip arthroplasty. The diagnosis was osteoarthritis in all patients. The angle between the IA (defined by a line connecting the anterior edge of the greater sciatic notch and the lesser sciatic notch) and APP (defined by the bilateral anterosuperior iliac spine and the symphysis) was measured on 3D-CT (Fig. 1). Secondly, postoperative lateral radiographs were obtained at 2 weeks, 4 weeks, 12 weeks, 24 weeks, and 52 weeks after surgery in 15 patients. The angle between a line tangential to the opening of the cup and a line perpendicular to APP was measured (Fig. 2). Three methods of acetebular cup position assessment were compared: 1) the present method, 2) Woo and Morrey method, and 3) software (2D template, Kyocera) method.Introduction:
Materials and Methods:
