There are few reports including natural course of initial gap in total hip arthroplasty. The purpose of this study is to investigate the incidence of initial gap in the PSL type shells and its natural course. Total of 386 THAs with Trident or TriAD PSL shells were performed between January 2000 and December 2014. Exclusion criteria were shells with screw fixations (n=189), previous pelvic osteotomy (n=15) and less than 3 years’ follow-up (n=11). Finally, our study included 171 hips. Average age was 56.8 (17∼83) years at THA and average follow-up time was 8.3 (3∼16.3) years; 112 (66%) were women; and 120 hips (70.2%) had osteoarthrosis. As radiographic evaluation, we checked presence or absence of initial gap, maximum size of it, gap filling and cup stability. The presence of initial gap was defined as gap present on post-operative anteroposterior X-ray measuring 1mm or greater. Gap filling was defined as confirmed trabecular formation between the cup and acetabular floor without cup migration. And we determined the time to gap filling. As clinical evaluation, we retrospectively checked Harris Hip Score (HHS) at pre-operative and final follow-up period, and presence of shell revision. Furthermore, we compared clinical results with or without initial gap.Background
Methods
Acetabular component loosening has been one of the factors of revision of total hip arthroplasty (THA). Inadequate mechanical fixation or load transfer may contribute to this loosening process. Several reports showed the load transfer in the acetabulum by metal components. However, there is no report about the influence of the joint surface on the load transfer. We developed a novel acetabular cross-linked polyethylene (CLPE) liner with graft biocompatible phospholipid polymer(MPC) on the surface. The MPC polymer surface had high lubricity and low friction. We hypothesized the acetabular component with MPC polymer surface (MPC-CLPE) may reduce load transfer in the acetabulum compared to that of the by CLPE acetabular component without MPC. We fixed the three cement cup with MPC-CLPE (Group M; sample No.1–3) and three cement cup with CLPE (Group C; sample No.4–6) placed in the synthetic bone block with bone cement with a 0.10mm thick arc-shaped piezoresistive force sensor, which can measure the dynamic load transfer(Tekscan K-scan 4400; Boston). (Fig 1) A hip simulator (MTS Systems Corp., Eden Prairie, MN) was used for the load transfer test performed according to the ISO Standard 14242-1. Both groups had same inner and outer diameter s of 28 and 50mm, respectively. A Co–Cr alloy femoral head with a diameter of 28 mm (K-MAXs HH-02; KYOCERA Medical Corp.) was used as the femoral component. A biaxial rocking motion was applied to the head/cup interface via an offset bearing assembly with an inclined angle of +20. Both the loading and motion were synchronized at 1 Hz. According to the double-peaked Paul-type physiologic hip load, the applied peak loads were 1793 and 2744 N described in a previous study. The simulator was run 3 cycles. We recorded both the peak of the contact force and the accumulation of the six times load in total. Secondly, we calculated the mean change of the load transfer. We used the Student t-test. P value < 0.05 was used to determine statistical significance. We used EZR for statistical analysis.Introduction
Methods
It has been reported that the tibial articular surface of coronal aligment is parallel to the floor in the whole-leg standing radiographs of the normal knee. The purposes of this study are to investigate the relationship between the tibial articular surface and the ground on the whole-leg standing radiographs after total knee arthroplasty(TKA). 20 knees after TKA were studied retrospectively. The 20 participants were mean age at 76.7 years; and 3 male and 17 female. Using whole-leg standing radiographs, we mesuared the pre- and postoperative hip-knee- ankle angle(HKA), the tibial joint line angle(TJLA), and the tibial component Coronal tibial angle(CTA). The difference in each parameter was compared and examined.Introduction
Sturdy Design and Methods
One-stage bilateral total hip arthroplasty (THA) is twice as invasive as unilateral THA. Therefore, increases in bleeding, postoperative anemia, and complications are a concern. The purpose of this study was to investigate hemoglobin values and the use of autologous and allogenic blood transfusion after one-stage bilateral THA. Twenty-nine patients (7 men and 22 women; 58 hips) were treated with one-stage bilateral THA. The mean age of subjects at the time of surgery was 60.6 years. The average body mass index for patients was 21.7 kg/m2. The diagnoses were secondary osteoarthritis due to developmental dysplasia of the hip (n=25) and avascular necrosis (n=4). All patients had donated 800 ml of autologous blood in 2 stages preoperatively (1 to 4 weeks apart). All patients took iron supplements starting from 5 weeks preoperatively. For all patients, the procedure was performed under general anesthesia in the lateral decubitus position via a posterolateral approach. Intra-operative blood salvage was not used. Suction drains were inserted subfascially. As a general rule, pre-donated autologous blood was transfused back to the patients intra- or post-operatively. Allogenic blood transfusion was performed when clinical symptoms of anemia occurred (hypotension, low urinary output, tachycardia, etc.) rather than using a preset blood threshold (hemoglobin level <8 g/dl). To determine changes in blood pressure following surgery until the next morning, systolic and diastolic blood pressure were measured at 3-hr intervals.Background
Methods
