Histologische untersuchungen über umbauvorgänge an der zement-knochengrenze bei endoprothesen nach 3-bis 10-jähriger implantation

Abstract

The prosthesis loosening represents the main complication of an endoprosthesis. When using bone cement for an anchorage, the most important factors of loosening are the impairment of tissue during toxical and thermic influence, foreign body reaction on the abraded material of the prosthesis, the resorption effect through foreign body giant cells as well as the parallel effect of monomer impoverishment and the dissapearance of polymerization matrix material. Histological examinations of the reparation proceedings of not loosened cement-bone surfaces at total endoprostheses are rarely found in literature, and the extent of a long term effect of the cement on the bone layer has not been sufficiently ascertained. To obtain an insight into the reaction of the bone tissue to the bone cement, the bone-cement surface was examined histologically after 3—10 years TEP-implanation. Material and Methods. Eleven specimens of roentgenology and macroscopic fixed bone cement-bone connexion of non-infected TEP were being studied. The interval between surgery and reoperation ranged from 3, 3,3, 3,5, 4, 4,7, 5, 5,4, 5,5, 7,11, 9, years to 10 years. Seven of the patients were females, four were males. The average age at the time of implantation was 69,4 years. Eight implantations corresponded to Miiller-Charnley hip TEP, three were "Kniehalbschlittenprothesen". The primary operation was made because of severe cox- or gonarthrose. For anchoraged of the protheses usual polymethylmethacrylate (PMMA) cement was used. The histological treatment based on the embedding in methylmethacrylate, undecalcefying sectioning and staintechnic specified by Burkhardt 1966 and Delling 1972 and 1980. Results. All specimens showed a strong increase of inactive osteoid on the bone-cement surface bordering. Additionally the appearance of a so called "Faserosteoid" and of none typical ossifying proceedings can be observed. These changes appeared most distinctly after 9 and 10 years of the prostheses implantation. One the strenght of the two studied specimen after 9 and 10 years implantation, we can not make a definite statement about a possible increase and deterioration. Discussion. According to Willert and Puls 1972 tissue reactions are terminating during the implantation which take place in three stages: First the implantation stage, secondly the regeneration stage and thirdly the stabilisation stage. According to their findings the stabilisation stage is reached at the latest after two years by the reparation proceedings of the bone bed. Morphometric tests on the skeletons of healthy people show a retarded secundary mineralisation in the sens of the "Altersmineralisationsstörung" with increasing tendency in the age group of 50-60 year-olds (Merz and Schenk 1970, Delling 1975). This already represents a bad start for bone reparation proceedings on older people. In our material there is morphologically a strong increase of inactive osteoid with isturbance of the regular mineralisation and the appearance of a so called "Faserosteoid". These changes might be attributed to local toxical influences caused by the cement or components of the cement like the aniline-blending Paratoluidine which could have an effect on the osteoblasts as well as on the proceedings of the mineralisation. Similiar increases of the osteoid are superficially mentioned by Willert and Puls 1972, 1974 A + B and Schuppler and Remagen 1976 and are believed to be a slow down of mineralisation. The formation of "Faserosteoid" as well as the appearance of atypical mineralisation proceedings have not yet been described as far as we know. These disturbances of mineralisation represent a loss of stabilisation of the bone-cement anchorage. At the punctiform overloading, lesions arise in this area, producing the growth of granulation-tissue which demolish the adiacent bone and result in the loosening of the prosthesis. The genuine aetiology of this disturbancy of mineralisation and a possible treatment or prophylaxy are object of additional investigation at the present time.