Primary stability of the Burch-Schneider ring (BSR) in case of acetabular revision is discussed controversial. In a retrospective two centre cohort study we analyzed the influence of the mode of screw fixation and the restoration of the center of rotation on migration, loosening and other radiographic parameters. Patients with a minimal radiographical follow-up of 2 years and suitable for EBRA analysis were included. In group 1 (46 patients) screws were placed through the cranial spherical part of the ring and covered by cement and cup, in group 2 (40 patients) screws were placed through the cranial flange. Preoperative bone defects were classified, the postoperative centre of rotation was determined. Changes of screws were recorded, migration exceeding >1mm was seen as significant.Introduction
Material/Methods
The usefulness of minimal invasive hip replacement is frequently discussed but there is a lack of data on the effect of the surgical approach on early results. We wanted to study the effect of the surgical approach on the peri- and early postoperative outcome. In a prospective case control study 315 elective hip replacements were performed between January 2008 and March 2010. Until March 2009 a lateral transgluteal approach (STD) was used, then the approach was changed to a minimal invasive anterior approach (MIS). All operations were performed in the same routine setting not affected by the approach. Duration of operation, complications and bloodloss were assessed. 1 week postoperatively, independent mobility, stairs, central analgetics were analysed and length of stay was recorded. At 6 and 12 weeks, pain and patients satisfaction (VAS) and the Harris Hip Score were assessed. Pre- and postoperative radiographs were compared for component position and orientation (EBRA).Introduction
Material/Methods
Osteolysis was found in 36 cups, 18 of them have been revised. The average linear wear was 1.1 (+/− 0.9) mm, the average wear volume 798.7 (+/−622.3) mm3, the linear wear rate 0.07 (+/−0.06) mm/year and the volumetric wear rate 54.5 (+/− 43.2) mm3/year. Younger patients had increased linear wear rates (p=0.035). Osteolysis of the cup, cup migration and cup revision were correlated with linear and volumetric wear (all p=<
0.001). There was no correlation of the cup position, inclination and anteversion with osteolysis, loosening and any of the wear parameters. Volume calculation did not provide further information.
The aim of this study was to obtain detailed long-term data on the cement-bone interface in patients with cemented stems, implanted using the constrained fixation technique. A total of eight stems were removed together with adjacent bone during Our results confirm that a complete cement mantle is not essential for the survival of Müller straight stems into the mid term, and support our hypothesis that no benefit to long-term survival can be expected from modern cementing techniques.
Aim of our study was to analyze cortical bone changes in prosthetic hips with time and compare those changes with the contra lateral non operated femur.
10 patients were not operated on the contralateral hip and were measured in standardized manner in the same locations as in THA femurs.
The original forged Müller straight stem (CoNiCr) has shown excellent ten- to 15-year results. We undertook a long-term survival analysis with special emphasis on radiological changes within a 20-year period of follow-up. In all, 165 primary total hip replacements, undertaken between July 1984 and June 1987 were followed prospectively. Clinical follow-up included a standardised clinical examination, and radiological assessment was based on a standardised anteroposterior radiograph of the pelvis, which was studied for the presence of osteolysis, debonding and cortical atrophy. Survival of the stem with revision for any reason was 81% (95% confidence interval (CI), 76 to 86) at 20 years and for aseptic loosening 87% (95% CI, 82 to 90). At the 20-year follow-up, 15 of the surviving 36 stems showed no radiological changes. Debonding (p = 0.005), osteolysis (p = 0.003) and linear polyethylene wear (p = 0.016) were associated with aseptic loosening, whereas cortical atrophy was not associated with failure (p = 0.008). The 20-year results of the Müller straight stem are comparable to those of other successful cemented systems with similar follow-up. Radiological changes are frequently observed, but with a low incidence of progression, and rarely result in revision. Cortical atrophy appears to be an effect of ageing and not a sign of loosening of the femoral component.
Clinical and radiological follow-up was planned at 4 months 1, 2, 5, 10, 15 and 20 years. Clinical follow-up included a standardised examination and the completion of an IDES form. Cumulative survival rates were calculated by Kaplan-Meier analysis. Radiographs were analysed for osteolysis according to Gruen et al. (zones 1–7) and radiolucent lines.
The median HHS at the last follow-up was 80 points (range 30–98 points). 31% of the non-revised 41 stems showed osteolysis, most of them in zone 7 (21.9%). Two stems with isolated cup revision had a continuous radiolucent line. Incomplete radiolucent lines appeared most frequently in zone 1. Cup revision was associated with increased radiological changes on the femoral side (p=0.094, Mann-Whitney U-test).