To compare the properties of wear debris between ceramic-on-ceramic and ceramic-on-polyethylene total hip prostheses, particles were isolated and characterized from tissue biopsies obtained at revision arthroplasty or autopsy from two similar uncemented modular hip systems. Group A hips (11 patients; mean, 31 months in vivo) had titanium shells with alumina inserts, alumina femoral heads, and titanium alloy stems. Group B hips (seven patients; mean, 42 months) were the same as Group A but with polyethylene acetabular inserts. Particles were characterized using an electrical resistance particle analyzer, scanning electron microscope, and energy dispersive xray spectroscope. Most of the particles in Group A were ceramic, whereas most of the particles in Group B were polyethylene. Metal particles from the femoral stem and the acetabular shell also were present. If one Group A hip with impingement is excluded, the rate of particle production is significantly lower in the ceramic-on-ceramic group than in the ceramic-on-polyethylene group. With the number of samples available, no significant difference in average size could be detected among the different types of particles or among the groups.

The current authors review clinical and retrieval experiences with hemispheric monolithic alumina ceramic sockets (Group 1), implanted between 1976 and 1979, and similar modular titanium sockets with alumina ceramic inlays (Group 2), implanted between 1990 and 1995. Both cementless sockets articulated with alumina ceramic femoral ball heads for total hip joint replacements. Clinical followup of patients with hemispheric monolithic alumina ceramic sockets (Group 1, 138 sockets) resulted in a total failure rate of 19.6% after 5 to 20 years. Radiologic analysis of eight stable sockets showed migration of 0.2 mm to 2.89 mm, but in four sockets at risk for late aseptic failure after an average followup of 12.5 years as much as 13.4 mm of migration was seen. Histologic evaluation revealed pseudosynovial membranes as thick as 1 mm with fine birefringent wear particles within mononuclear macrophages around two stable retrieved sockets. The membranes around four loose sockets were 6 to 10 mm thick and also heavily loaded with larger alumina wear particles. After 7 years followup clinical analysis of patients with modular titanium sockets with alumina ceramic inlays (Group 2, 30 sockets) resulted in four revisions, compared with one revision of 50 identical sockets (control group) with polyethylene instead of alumina ceramic inlays. Wear particle analyses in scanning electron microscopy showed significantly more particles (x 10(9) +/- standard deviation/g dry tissue) from the control group (4.26+/-6.38), compared with alumina ceramic bearings of Group 1 (0.70+/-0.79), and of Group 2 (1.62+/-2.13). The alumina particle sizes ranged between 0.13 and 78.38 microm. The mean annual linear wear of 38.8 microm was calculated for the bearings in Group 1, and of 26.94 microm for bearings in Group 2. These results support the good tribologic and biologic performance of alumina ceramic bearings for total hip arthroplasty.

We compared wear particles from two different designs of total hip arthroplasty with polycrystalline alumina-ceramic bearings of different production periods (group 1, before ISO 6474: group 2, according to ISO 6474). The neocapsules and interfacial connective tissue membranes were retrieved after mean implantation times of 131 months and 38 months, respectively. Specimen blocks were freed from embedding media, either methylmethacrylate or paraffin and digested in concentrated nitric acid. Particles were then counted and their sizes and composition determined by SEM and energy-dispersive x-ray analysis (EDXA). The mean numbers and sizes of most alumina wear particles did not differ for both production periods, but the larger sizes of particle in group 1 point to more severe surface destruction. The increased metal wear in group 2 was apparently due to alumina-induced abrasion of the stems. In this study the concentrations of particles in the periprosthetic tissues were 2 to 22 times lower than those observed previously with polyethylene and alumina/polyethylene wear couples.

41 draining sinuses after THR were treated by debridement without exchanging the implants. Positive bacterial cultures were obtained in 23 patients-the ilio tibial tract was found open in 19 cases (82%). The bacterial cultures were negative in 18 patients-the ilio tibial tract was found open in 7 cases (38%). Revisions took place 21 days (9-43) after primary implantation. At the time of the follow up (0 72 months postoperatively) 7 patients had been revised (8-97) because of recurrence of infection. The results of debridements of contaminated sinuses depend on the ilio tibial tract. Revisions were successful in three out of four paces with an intact, and only in eight out of nineteen cases with an open ilio tibial tract. Besides proper bacterial investigation preoperative sinograms give useful information about the prognosis of revision. In cases with positive bacterial cultures debridements should be done very early to eradicate infection without removing the implants.

41 draining sinuses after THR were treated by debridement without exchanging the implants. Positive bacterial cultures were obtained in 23 patients-the ilio tibial tract was found open in 19 cases (82%). The bacterial cultures were negative in 18 patients-the ilio tibial tract was found open in 7 cases (38%). Revisions took place 21 days (9-43) after primary implantation. At the time of the follow up (0 72 months postoperatively) 7 patients had been revised (8-97) because of recurrence of infection. The results of debridements of contaminated sinuses depend on the ilio tibial tract. Revisions were successful in three out of four paces with an intact, and only in eight out of nineteen cases with an open ilio tibial tract. Besides proper bacterial investigation preoperative sinograms give useful information about the prognosis of revision. In cases with positive bacterial cultures debridements should be done very early to eradicate infection without removing the implants.

We report the clinical and tribological performance of 67 ceramic acetabular prostheses implanted between 1976 and 1979 without bone cement. They articulated with ceramic femoral heads mounted on mental femoral stems. After a mean elapsed period of 144 months, 59 sockets were radiographically stable but two showed early signs and six showed late signs of loosening. Four of the loose sockets have been revised. Histological analysis of the retrieved tissue showed a fibrous membrane around all the implants, with fibrocartilage in some. There was no bone ingrowth, and the fibrous membrane was up to 6 mm thick and infiltrated with lymphocytes, plasma cells, and macrophages. Intra- and extracellular birefringent wear particles were seen. Tribological analysis showed total wear rates in two retrieved alumina-on-alumina joints of 2.6 microns per year in a stable implant and 68 microns in a loose implant. Survival analysis showed a revision rate of 12.4% at 136 months.

Limb salvage procedures in the treatment of malignant bone tumors of the upper extremity have been performed in Vienna since the early 1970s [1,4–6]. Endoprostheses with different anchorage systems and made of various materials have been constructed to obtain a maximum of function and long-term stability with a minimum oflocal tissue irritation. Consequently this led to systems which relied on a biological fixation in the bone without the use of bone cement. Improvements of constructional details like the use of adequate materials and surface structures together with extracortical or intramedullary fixation were partly based on histological findings on retrieved implants. This study summarizes our experience in 15 cases of retreieved humerus endoprostheses.

Seventy patients who had a rotationplasty for treatment of a malignant tumor in the region of the knee (the femur or the tibia) between 1974 and 1987 were followed for two to thirteen years (mean duration of follow-up, four years). Forty-seven patients had a stage-IIB osteosarcoma; the remaining twenty-three patients had a malignant fibrous histiocytoma, a chondrosarcoma, a Ewing sarcoma, or a giant-cell tumor.The most severe postoperative complication was occlusion of the reanastomosed vessels (seven patients), leading to amputation proximal to the knee in three patients. Other complications were problems with wound-healing (eight patients), transient nerve palsy (five patients), irreversible nerve palsy (two patients), pseudarthrosis (four patients), and rotational malalignment (one patient). Late complications included eight fractures, two infections, two delayed unions, and one lymphatic fistula. More than half of the patients were free of complications related to the operative procedure.Forty-four of the patients who had a stage-IIB osteosarcoma could be followed, and their data were analyzed for survival statistics. These patients had a 58 per cent rate of disease-free survival and a 70 per cent rate of over-all survival. One patient had a local recurrence five years after the operation.

Between 1973 and 1979, ceramic tumor endoprostheses were used in 40 patients treated at the Orthopedic Hospital Wien-Gersthof. The main localization was the proximal humerus, where 25 ceramic endoprostheses were implanted, followed by the proximal femur with ten implants. Elongation of a femoral stump after high amputation was performed in three cases, while in two cases after above-knee amputation and disarticulation of the femur a special disarticulation endoprosthesis was implanted.

Rotationplasty is a standard method of surgery for treatment of malignant bone tumors of the distal part of the femur. Compared with the hitherto accepted methods of limb salvage—endoprosthesis, allograft, and resection arthrodesis—rotationplasty seems to give better oncological and functional results. Thus far, at the Orthopedic Hospital Vienna, we have had experience of 49 cases of rotationplasty with a follow-up of 3–10 years. With respect to the emotional acceptance of this method, the results of this study were particularly revealing.

An der allgemeinen orthopädischen Abteilung des Krankenhauses Gersthof in Wien wurde Ende Mai 1981 mit der zementfreien Implantation der Knietotalendoprothese des Typs PCA begonnen. Seit Mitte 1987 wird an unserer Abteilung nun mehr die Knieprothese des Typs Miller-Galante implantiert, da bei diesem Prothesenmodell eine umfassendere Anzahl von Implantatgrößen zur Verfügung steht und somit eine bessere Adaptation an anatomische Gegebenheiten ermöglicht.

The influence of thrombosis prophylaxis on the occurrence of heterotopic ossification after implantation of total hip endoprostheses was analyzed in a series of randomized studies. When low-dose heparin or dextran 40 was administered, the rate of ossification was comparatively high (30.1% and 65.1%). When a combination of acetylsalicylic acid and an antirheumatic (oxyphenbutazone) or low-dose heparin with an antirheumatic (indomethacin) was administered, the ossification rate became significantly lower (6.2% and 16.7%). No severe ossification (Arcq degree III) was observed in the groups given an antirheumatic in addition to thrombosis prophylaxis.

The acetabular socket "Model Gersthof" is a spheric polyethylene component which can be anchored cement-free by means of three symmetrically arranged pegs at the outside. Between July 1979 and October 1986, 1316 implants of cement-free sockets were performed at our own department. The evaluation of the socket was based on the criterium of radiological instability (= aseptic loosening). After five years of observation, this design-oriented evaluation of success shows a survival of 92% +/- 2.9%.

Follow-up examinations of 67 implants of cement-free ceramic sockets show the need for an exact definition of failure, to warrant comparable evaluations of results. Statistical survival analysis offers the possibility of presenting both the incidence of failures and the dates of their occurrence. If only revision surgery with removal of the socket is considered to be a failure, our material shows the “survival quota” of the ceramic socket after 8 years to be 96.7% ± 2.2%. If radiological signs of loosening are included in the evaluation of failures, the “survival quota” of the stable implants is reduced to 81.9% ±6.9%.

43 cases of tumor resection followed by ventral stabilisation are reported in 42 patients with metastases in the spine. Indications for surgery were beginning or incomplete transversal lesion of the spinal cord, bedrest for at least 3 weeks, unsusceible pain caused by instability, or unsuccessful conservative and radiotherapeutic treatment. 46.5% of the cases can be rated as good considering the time of survival and life quality, 18.5% can be judged as a partial success. 7 patients hat to be reoperated in the same level, most of them because of local recurrence. Complications occurred in 40% of the cases. These operations should be performed by a "term of specialists". Postoperative treatment with isotope-, hormone- or radiotherapy is decisive to obtain good results.

Die Wirbelsäule stellt innerhalb des Skelettsystems die häufigste Lokalisation metastatischer Absiedelungen dar (Jaffe 1958). In der Mehrzahl der Fälle sind die Wirbelkörper selbst betroffen, daher kann es durch direkten Druck auf die Dura von ventral zu schwerwiegenden neurologischen Folgen kommen, außerdem können pathologische Frakturen und Wirbelkörpereinbrüche eine hochgradige Instabilität der Wirbelsäule bewirken. Bei diesen Folgeerscheinungen des Tumorbefalles können sowohl die konservative orthopädische Behandlung als auch die Strahlentherapie nur vereinzelt zum Erfolg führen (Harrington 1981). Die Tumormassen können bei Wirbelköperbefall durch die Laminektomie nicht beseitigt werden. Außerdem wird die Instabilität durch die Laminektomie zusätzlich erhöht (Callahan u. Mitarb. 1977, Kennady und Stern 1962). Aus diesen Gründen ist bei metastatischem Befall des Wirbelkörpers relativ häufig die Indikation zur Tumorausräumung und anschließender Stabilisierung von ventral gegeben. Salzer u. Mitarb. legten die Prinzipien der Indikationsstellung und Operationsplanung sowie -durchführung 1975 dar. Die vorliegende Studie berichtet nun über unsere Erfahrungen mit der nach diesen Prinzipien durchgeführten ventralen Wirbelmetastasenbehandlung.

Among the unsolved problems of hip replacement arthroplasty is the question of how to anchor a prosthetic stem permanently in the femoral shaft. Because the traditional fixation of endoprostheses with bone cement is associated with a high incidence of loosening [2, 6, 7], increased attention has been focused on means of anchoring femoral endoprostheses permanently without the use of cement [3, 4, 5, 8, 9]. In the present paper we shall describe our own attempts to develop a new design for an uncemented stem endoprosthesis.