Acetabular dysplasia is a common cause of osteoarthritis of the hip. Chiari pelvic osteotomy enables medialization of the center of the femoral head and improvement of coverage over the femoral head for hip dysplasia and prevents or delays progression of degenerative arthritis. We reviewed 104 patients after this augmentation procedure. Between 1989 and 2000, 167 patients with developmental dysplasia of the hip had undergone the surgery at university hospital. Among them, 104 patients were able to be traced after surgery for more than 10 years. The mean follow-up period was 15.5 years. There were 96 women and 8 men with an average age of 34.3 years at surgery. The average angle of osteotomy was 6.6 degree craniad to the horizontal plane. Ratio of migration of the distal pelvis was 42%.Introduction
Patients and methods
The goal of total hip arthroplasty (THA) should be to reconstruct the acetabulum by positioning the hip center as close as possible to the anatomical hip center. However, the true position of the anatomic hip center can be difficult to determine during surgery on an individual basis. In 2005, we designed, produced an acetabular reaming guide, and clinically used to enable cup placement in the ideal anatomical position. This study was examined the accuracy the reaming guide for THA in prospective study. This guide was applied consecutive 230 patients in primary THA. During planning, the distance from the acetabular edge to the reaming center and from the center to the perpendicular of the inter-teardrop line was measured on an anteroposterior (AP) X-ray. The reaming guide was adjusted depend on the reaming center by based planning. Acetabular reaming was performed with the process reamer.Introduction
Methods
The frequency of venous thrombo-embolism (VTE) after total hip arthroplasty(THA) is 20–30% and it is serious complication under THA. Therefore it is necessary to detect and prevent VTE. The purpose of this study were examined the frequency of VTE and the factor of incidence of VTE in our hospital. The 615 patients(82 men and 533 women) who performed primary THA from Jan. 2006 to Apr. 2011 were examined in this study. The Average age at the operation was 65 years (rage, 20–92 years). MDCT examination was performed the day after operation to detect VTE. 95 patients(15.4%) were positive of VTE and the rest of them were negative. We examined the age at operation, body mass index(BMI), blood loss, operative time, blood soluble fibrin monomer complex(SFMC) in the positive and negative group of VTE. The distance from the tibial joint line to the level of DVT was measured.Purpose
Patients and methods
We have used CT-based total hip navigation system from 2003, to set the acetabular socket in optimal position. At first, we had used CT-based land-mark matching system. It needs matching procedure during surgery, touching paired points in surgical exposure. From 2006, we started to use new navigation system, called CT-based fluoroscopy-matching system, which was developed by BrainLAB Company (Vector-vision 2.7.1., 3.5.1.). For this new system, pre-surgical image matching procedure is need. Fluoroscopic images with 2 different directions must be taken in operation room. Then fluoroscopic images and CT reconstructive images were matched in computer with special program. Matching procedure was done before surgical incision. We compared the advantage of these two systems about technical problem, radiation exposure, time need for procedure, and accuracy. And then we discussed how to use these two different systems for THA patients. Accuracy was compared for 241 THA patients using these navigation systems. 152 cases were with CT-based land-mark matching system and 89 patients with CT-based fluoroscopy matching system. Final verification angle of acetabular socket setting in navigation during surgery was recorded for each case. The operative angle, which is referred from Murray, is used to show the socket setting angle (inclination and anteversion) in these navigation systems. Post-operative CT scan was taken to evaluate the actual socket setting angle. The values between verification angle during surgery and post-operative CT measured angle were calculated and compared statistically. Results were followed.
For ordinary THA cases with skilled-doctor, CT-based land-mark matching system is useful, because this system is very convenient and needs only extra 10 minutes during surgery. For severe deformed cases with all kind doctors, CT-based fluoroscopy matching system is useful, because this system showed high accuracy even for severe deformed cases. Before surgical incision, fluoroscopic matching procedure has finished. This system needs no extra time after surgery starts.
In the light of the increasing popularity of femoral resurfacing implants, there has been growing concern regarding femoral neck fracture. This paper presents a detailed investigation of femoral neck anatomy, the knowledge of which is essential to optimise the surgical outcome of hip resurfacing as well as short hip stem implantation. Three-dimensional lower limb models were reconstructed from the CT-scan data by using the Mimics (Materialise NV, Leuven, Belgium). We included the CT data for 22 females and nine males with average age of 60.7 years [standard deviation: 16.4]. A local coordinate system based on anatomical landmarks was defined and the measurements were made on the unaffected side of the models. First, the centre of the femoral head was identified by fitting an optimal sphere to the femoral head surface. Then, two reference points, one each on the superior and the inferior surface of the base of femoral neck were marked to define the neck resection line, to which an initial temporary neck axis was set perpendicular. Cross-sectional contours of the cancellous/cortical border were defined along the initial neck axis. For each cross-sectional contour, a least-square fitted ellipse was determined. The line that connects the centre of the ellipse at the base of the femoral neck and the centre of the femoral head was defined as the new neck axis. The above process was repeated to reduce variances in the estimation of the initial neck axis. The neck isthmus was identified according to the axial distributions of the cross-sectional ellipse parameters. The short axis of the ellipse decreased monotonically since it was calculated from the center of the femoral head to the neck resection level (base of neck), whereas the long axis changed with the local minima. The cross section at which the long axis of the fitted ellipse had the local minima was determined as the neck isthmus. The following measurements were made on the proximal part of the femur. The neck axis length measured from the center of the femoral head to the lateral endosteal border of the proximal femur was 67.3 mm [6.4]. The length between the center of the femoral head and the neck isthmus was 22.5 mm [2.7]. The diameter of the ellipse long axis at the neck isthmus was 27.6 mm [3.5] and was 23.6 mm [3.3] for the short axis. The center of the neck isthmus did not align with the neck axis. The deviation of the isthmus from the neck axis which we defined as the isthmus offset was 0.7 mm [0.4]. If an alternative neck axis was defined between the center of the femoral head and the center of the neck isthmus, there would be a certain degree of angular shift with respect to the original neck axis. An angular shift of 1.8 degrees between the two axes can be expected for a 0.7-mm isthmus offset. In the worst case, an angular shift of 4.59 degrees was estimated for a subject with the largest isthmus offset of 1.93 mm. Further investigations would be necessary to determine the axis configuration that represents the clinically relevant centre of the femoral neck. In order to reduce the deviations in the three-dimensional determination of the femoral neck axis, the reference anatomical landmarks and methods of evaluation should be carefully selected.
