We analysed the histological findings in 1146 osteoarthritic femoral heads which would have been considered suitable for bone-bank donation to determine whether pathological lesions, other than osteoarthritis, were present. We found that 91 femoral heads (8%) showed evidence of disease. The most common conditions noted were chondrocalcinosis (63 cases), avascular necrosis (13), osteomas (6) and malignant tumours (one case of low-grade chondrosarcoma and two of well-differentiated lymphocytic lymphoma). There were two with metabolic bone disease (Paget's disease and hyperparathyroid bone disease) and four with inflammatory (rheumatoid-like) arthritis. Our findings indicate that occult pathological conditions are common and it is recommended that histological examination of this regularly used source of bone allograft should be included as part of the screening protocol for bone-bank collection. (+info)
Histopathology of retrieved allografts of the femoral head.
(2/16)
From November 1994 to March 1997, we harvested 137 grafts of the femoral head from 125 patients for donation during total hip arthroplasty according to the guidelines of the American Associations of Tissue Banks (AATB) and the European Association of Musculo-Skeletal transplantation (EAMST). In addition to the standards recommended by these authorities, we performed histopathological examination of a core biopsy of the retrieved bone allograft and of the synovium. Of the 137 allografts, 48 (35.0%) fulfilled all criteria and were free for donation; 31 (22.6%) were not regarded as suitable for transplantation because the serological retests at six months were not yet complete and 58 (42.3%) were discarded because of incomplete data. Of those discarded, five showed abnormal histopathological findings; three were highly suspicious of low-grade B-cell lymphoma, one of monoclonal plasmacytosis and the other of non-specific inflammation of bone marrow. However, according to the standards of the AATB or EAMST they all met the criteria and were eligible for transplantation. Our findings indicate that the incidence of abnormal histopathology in these retrieved allografts was 3.6%. Since it is essential to confirm the quality of donor bones in bone banking, we advise that histopathological screening of donor bone should be performed to exclude abnormal allografts. (+info)
Changes in allograft bone irradiated at different temperatures.
(3/16)
Secondary sterilisation of allograft bone by gamma irradiation is common, but the conditions under which it is performed vary between tissue banks. Some do so at room temperature, others while the bone is frozen. Bone is made brittle by irradiation because of the destruction of collagen alpha chains, probably mediated by free radicals generated from water molecules. Freezing reduces the mobility of water molecules and may therefore decrease the production of free radicals. We found that bone irradiated at -78 degrees C was less brittle and had less collagen damage than when irradiated at room temperature. These findings may have implications for bone-banking. (+info)
Study of the healing process after transplantation of pasteurized bone grafts in rabbits.
(4/16)
Different bone allografts (pasteurized, autoclaved, and frozen) were compared based on their osteoinductive properties. Our primary purpose was to examine the biologic qualities of pasteurized allografts, as pasteurization inactivates most viruses transmitted by transplantation. Frozen, pasteurized, and autoclaved allografts were packed into a standard defect of rabbit ulna. The animals were sacrificed at 2 and 4 weeks after surgery. The parts of bones with experimental defects were explored en bloc, and a roentgenogram was carried out. Ulna bone samples were then embedded in methyl-methacrylate. Roentgenograms showed that after 2 weeks, calluses were well-formed, but irregular in shape in all 3 types of allografts. After 4 weeks, the calluses were regular in shape in all but the autoclaved grafts. After 2 weeks, the healing processes had begun in the frozen and pasteurized grafts, with the reaching approximately the same stage, while in the autoclaved grafts these processes were not seen and the bone particles were surrounded by connective tissue without any changes. After 4 weeks, osteoinductive processes were very strong, with the first signs of complete bone remodeling at the bone edges of the defect in pasteurized and frozen allografts. The osteoinductive values of these 2 types were very high and similar. Autoclaved allografts, on the other hand, had very low osteoinductive values, as they were still at the very beginning of the healing process. Histomorphometric analysis revealed a significant difference in both newly formed osteoid thickness and osteoblast number per microm of bone surface in all experimental groups (P < 0.005). Values of osteoid thickness and osteoblast number were significantly higher in both frozen and pasteurized grafts when compared with the autoclaved ones (P < 0.005). Osteogenic properties of pasteurized bone allografts were preserved, and the allografts have been gradually replaced with newly formed bone. As such, pasteurized bone grafts from a bone bank have approximately the same biologic validity as frozen grafts, while autoclaved grafts impair bone healing. (+info)
Microwave sterilization of femoral head allograft.
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The potential shortage of allograft bone has led to the need to investigate other sources of bone for allografts. Some allograft bone donated from primary total hip arthroplasty recipients must be discarded or treated to become usable as a result of bacterial contamination. Femoral head allografts were contaminated with Staphylococcus aureus and Bacillus subtilis. A domestic microwave oven was used. The contaminated bone was exposed to microwave irradiation for different time periods. The samples were then cultured to attempt to grow the two bacterial species. The contaminated bone samples failed to grow any organisms after 2 min of exposure to microwave irradiation. This study shows that sterilization of femoral head allografts contaminated with S. aureus and B. subtilis can be achieved with microwave irradiation in a domestic microwave oven. This method of sterilization of bone allografts is cheap, easily used, and an effective way to process contaminated bone. (+info)
Microbiological culture results for the femoral head. Are they important to the donor?
(6/16)
We determined the rate of contamination of donated femoral heads at primary hip arthroplasty within a single region between July 1992 and July 2001. We established the null hypothesis that culture results played no role in predicting early failure of the joint because of infection. The rate of contamination was 9%. A positive culture, at the time of retrieval, was found in 367 of 4045 femoral heads. Coagulase-negative staphylococcus was isolated in 77% of the positive cases. At a minimum follow-up of one year, there was no statistically significant difference in the rate of complications or of revision of age-matched patients whose femoral heads had a positive culture compared with those whose femoral heads were sterile. Our findings confirm that culture of the femoral head plays no part in determining future failure of joint replacement in the donor. (+info)
Microbial contamination of femoral head allografts.
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OBJECTIVE: To study the incidence of microbial contamination at the bone bank of the United Christian Hospital. DESIGN. Retrospective study. SETTING: Regional hospital, Hong Kong. PATIENTS: A total of 151 patients (33 men and 118 women) who underwent hip arthroplasty surgery and from whom femoral head allografts were retrieved between January 1994 and March 2000; and 81 patients in whom allografts were implanted. MAIN OUTCOME MEASURES: Bone biopsies were taken from the femoral head and used to detect any microbial contamination that might have occurred during removal and after storage. The rates of infection among recipients and donors were also assessed. RESULTS: Of the 151 allografts, 94 non-contaminated allografts were implanted by the end of the study. Fourteen (9.3%) heads showed positive culture results after retrieval and were discarded. Four (4.3%) of the 94 stored allografts that were implanted tested positive for microbial growth, but the recipients of these allografts did not develop any clinical infection. Three (3.2%) had wound infections after implantation of the stored allografts although the grafts had previously been tested negative for any microbial contamination. CONCLUSION: Our centre has a low allograft contamination rate. The wound infection rate among recipients was also low. The culture of a bone biopsy sample is a reliable method to detect contamination of bone grafts. However, the contamination rate among stored allografts should prompt orthopaedics departments to review allograft handling procedures, so as to minimise the chance of contamination. (+info)
Microbiological cultures of allografts of the femoral head just before transplantation.
(8/16)
Allografts of bone from the femoral head are often used in orthopaedic procedures. Although the donated heads are thoroughly tested microscopically before release by the bone bank, some surgeons take additional cultures in the operating theatre before implantation. There is no consensus about the need to take these cultures. We retrospectively assessed the clinical significance of the implantation of positive-cultured bone allografts. The contamination rate at retrieval of the allografts was 6.4% in our bone bank. Intra-operative cultures were taken from 426 femoral head allografts before implantation; 48 (11.3%) had a positive culture. The most frequently encountered micro-organism was coagulase-negative staphylococcus. Deep infection occurred in two of the 48 patients (4.2%). In only one was it likely that the same micro-organism caused the contamination and the subsequent infection. In our study, the rate of infection in patients receiving positive-cultured allografts at implantation was not higher than the overall rate of infection in allograft surgery suggesting that the positive cultures at implantation probably represent contamination and that the taking of additional cultures is not useful. (+info)