No abstract

A new surgical procedure, semiarthroscopic synovectomy of the hip is described. The operation enables a radical synovectomy to be performed without the risk of necrosis of the femoral head from temporary luxation. The early results have been encouraging and the method appears to offer a low-risk alternative to conventional radical synovectomy.

Background/Aims: To elucidate the influence and mode of action of HMR1726 (the active metabolite of leflunomide) on TNF-a and IL-17 activated metalloproteinases expression in synoviocytes. Methods: Synovial fibroblasts from RA and OA patients were stimulated with both cytokines and altered gene expression in the presence or absence of leflunomide was detected by microarray analyses and quantitative RT-PCR. Protein expression was detected by western blotting and commercial ELISAs. Results: Microarray analyses revealed that the addition of HMR1726 (50µM) to TNF-a and IL-17- stimulated synoviocytes induced gene expression of metallo-proteinases, especially MMP-1 and -3 in comparison to activated synoviocytes in the absence of leflunomide. To confirm these data, we examined the influence of different concentrations of HMR1726 in synoviocytes from further 5 OA and 7 RA patients by quantitative PCR. HMR1726 gradually induced MMP-1 and MMP-3 gene expression in a dose-dosedependent manner. Similar results were observed on protein levels. Examination of signal transduction pathways participating in the regulation of leflunomideinduced MMPs expression showed that the mechanism underlying activation of MMP-1 is in part p38- and activation of MMP-3 was MEK1/2- dependent. Conclusion: Leflunomide was not able to abolish expression of metallo-proteinases in synoviocytes activated with TNF-a and IL-17.

In case of non cemented fixation of prosthesis an extensive osseointegration is a precondition to obtain long lasting biological anchorage of the implant. The aim of the presented study was to analyse, whether the use of biactive materials (in case of prostheses-hydroxylapatit-coating-) provides advantages concerning the quality of anchorage compared to biotolerant or bionert materials. The influence of grade of biocompatibility of materials, the surface structure, the period of investigation and weightbearing on the osseointegration of implants was evaluated in an animal experimental study. New Zealand White rabbits got implanted cylinders in the non weightbearing series and spacers in the weightbearing series in the distal femur. The implant materials were spongy metal, porous coated titanium and hydroxylapatit coated titanium. After the experimental period of 4, 8 respectively 12 weeks the implant bearing femur underwent histological, morphometrical and scanning electromicroscopical investigation. The amount of osseointegration was determined by using the automatical image analysis. The percentage of new build bone was investigated by fluorescence microscopy and the adhesive power by push out tests. For non weightbearing implants higher adhesive powers were measured compared to hydroxylapatit coated implants while osseointegration was identic. All primary press-fit anchored weightbearing implants showed osseointegration. In hydroxylapatit coated specimen the most intensive osseointegration was found however without influence on the adhesive power. This fact was caused by the delamination of the plasma coating as consequence of the insufficient attachment of the hydroxylapatit coat to the metal nucleus.