We treated 60 hips in 60 patients (8 males and 52 females) with cementless THA that were performed from January 2007 to December 2009 in our hospital. 48 osteoarthritis hips, 5 rheumatoid arthritis hips and 7 idiopathic osteonecrosis hips were included. All patients were performed THA with VectorVision Hip navigation system (BrainLAB, Feldkirchen, Germany). We used AMS HA cups and PerFix stems (KYOCERA Medical co., Osaka, Japan). The mean age of surgery was 61 years old (35–79 years old). The pelvic inclination angles (PIA) were measured with anteroposterior radiographic image in accordance with the Doiguchi's method. The amount of change of the pelvic inclination angle between supine and standing position was 0.6 degrees prior to surgery, 0.7 degree at 1 year after surgery and 2.4 degrees at 5 years after surgery. 7 patients prior to surgery, 7 patient at 1 year after surgery and 18 patient at 5 year after surgery changed more than 5 degrees between supine and standing position. The pelvic inclination angles of 23 patients prior to surgery, 19 patients at 1 year after surgery and 35 patients at 5 years after surgery changed in the retroverted direction with posture change. It tended to increase after surgery.Materials and Methods
Results
CT-based navigation system in total hip arthroplasty(THA) is widely used to achieve accurate implant placement. The purpose of this study was to evaluate the influence of initial error correction according to the differences in the shape of the acetabulum, and correction accuracy associated with operation approach after localization of registration points at anterior or posterior area of the acetabulum. We set the anterior pelvic plane(APP) as the reference plane, and defined the coordinates as follows: X-axis for external direction, Y-axis for anterior direction, and Z-axis for proximal direction. APP is defined by the anterior superior iliac spines and anterior border of the pubic symphysis. We made a bone model of bilateral acetabular dysplasia of the hip, after rotational acetabulum osteotomy(RAO) on one side, and performed registration using infrared-reflective markers. At first, we registered the initial error on navigation system, and calculated the accuracy of the error correction based on each shape of the acetabulum as we increased the surface matching points. Based on the actual operation approach, we also examined the accuracy of the error correction when concentrating the matching points in anterior or posterior areas of the acetabulum.Background
Methods
The shape of proximal femur is important for the selection of implant in total hip arthroplasty (THA). There are few reports about the shape of proximal femur. We analyzed preoperative and postoperative conditions of the proximal femurs of patients before and after total hip arthroplasty with computed tomography (CT) and evaluated the compatibility to the cementless stem. We analyzed 65 hips of 63 patients (10 males and 53 females) who had THA between January 2008 and December 2010 in our hospital. We approximated the center of the femoral head as the center of the inscribed sphere in the femoral head. We defined the axis of proximal femur with the line between the centers of the circles located at 45 mm distal from lesser trochanter (LT) and at 90 mm proximal from LT. We measured the neck-shaft angle of femur, offset of femoral head, and diameter of bone-marrow cavity. After operation, we measured the distance between the stem surface and the edge of the femoral cortex (SF) at 10 mm proximal from LT to evaluate the compatibility of CT. We used PerFix HA cementless stem (Kyocera medical co., Osaka).Objectives
Materials and Methods
The main factor of osteoarthritis (OA) of the hip in Japan is secondary due to developmental dislocation of the hip and hip dysplasia. For this reason, navigation is useful to treat complicated cases. We performed total hip arthroplasty (THA) for the secondary OA of the hip using paired point matching and fluoroscopic matching, and compared the accuracy between them.Background
Purpose
The setting angle of the cup is important for achieving the stability and avoiding the dislocation after total hip arthroplasty (THA). It is difficult to set the cup at correct angle in minimally invasive THA by modified Watson-Jones approach. So we use CT-based navigation system. We evaluated the accuracy of with post-operative CT data. We treated 30 hips in 30 patients (7 male and 23 females) by navigated THA. 26 osteoarthritis hips, 2 rheumatoid arthritis hips and 2 idiopathic osteonecrosis hips were performed THA with VectorVision Hip 3.5.2 navigation system (BrainLAB). Implants were AMS HA cups and PerFix stems (Kyocera Medical, Osaka). Appropriate angles and positions of cups were decided on the 3D model of hip joint before operation. According to the preoperative planning, we put the cups with navigation system and stems without navigation system. We measured the anteversion angle with post-operative CT data and 3-dimensional template software.Objectives
Materials and Methods
CentPillar GB HA stem (stryker®) is developed as the stem fitting the Japanese femur, and now there is CentPillar TMZF HA stem (stryker®) as the improvement type of the stem by coating the PureFix HA with plasma spray. We observed the factors which influenced on the stem subsidence between the two-type stems. We intended for 26 hips 23 patients that we performed total hip arthroplasty (THA) during the period between January 2005 and June 2009 and were able to follow up more than three years. 10 males 11 hips and 13 females 15 hips, the mean age at the time of surgery was 56.5 (range, 29–74) years old, and primary diseases were osteoarthritis (OA) in 17 hips, Idiopathic Osteonecrosis of Femoral Head (ION) in six hips, and rheumatoid arthritis (RA) in three hips. 16 hips were treated with the CentPillar GB HA stem (G group), and 10 hips were performed with the CentPillar TMZF HA stem (T group). The examination items are the stem size, the canal fill ratio of the stem (the top of lesser trochanter, the bottom of lesser trochanter, the distal portion of the stem) and the stem alignment (on anteroposterior radiograph and Lauenstein view).Purpose
Materials and Methods
