INTRODUCTION: Alumina on alumina friction couple has proven its reliability in the field of total hip arthroplasty. However, loosening of the alumina socket has been responsible for most of the failures. An improvement of the bone/alumina interface could be achieved with the use of an osteconductive material as a coating on alumina. The aim of this study was to evaluate the osteconductive properties of two types of bioactive glasses as a coating on alumina substrates. MATERIALS AND METHODS: Two types of coated implants (silicate glass coated alumina - AVSi, and phosphate glass coated alumina - AVP) were evaluated in a rabbit cancellous bone model. Pure alumina implants (A) were used as negative controls and bulk glasses (silicate - VSi and original 45S5, and phosphate glasses -VP) as negative controls. Sacrifices were performed at 3, 12 and 24 weeks. The interface evaluation included histomorphometry using an image analyzer. RESULTS: Silicate glasses demonstrated high osteoconductive properties. However, non mineralized osteoid tissue was the main tissue in contact with both coated implants and bulk phosphate glasses. This tissue covered over 70 p. 100 after 24 weeks of implantation, while it was never observed around pure alumina implants after 3 weeks. DISCUSSION: Amongst the hypotheses that could explain this mineralization inhibitory process, the one involving an Al(3+) glasses contamination from Al(2) O(3) is the likeliest. The high temperature coating procedure could be responsible for alumina transformation into a more soluble phase.

Aluminum Oxide↗

PubMed2000

[Cementless acetabular fixation with solid alumina sockets. Apropos of 62 total hybrid prostheses with press-fit alumina sockets at 6-year mean follow-up].

PURPOSE OF THE STUDY: In order to avoid polyethylene wear observed in total hip replacement, an alumina-alumina combination has been used since 1977. The aim of this prospective study was to assess the results of an alumina-alumina total hip arthroplasty with a cementless press-fit plain alumina socket and a cemented titanium alloy stem with special attention for socket fixation because of previously encountered problems. MATERIALS AND METHODS: Fifty-five patients (62 hips) were operated on between 1982 and 1990. The main parameter for inclusion was a high level activity demand. The bearing surfaces were a 32 mm alumina head articulating within the alumina socket. Mean follow-up was 6 years. RESULTS: Four revisions occurred in this series: 3 for aseptic loosenings of the socket and 1 for femoral head fracture. Considering acetabular revision for aseptic loosening as the end point, the survival rate was 93.2 % at six years and 78.8 % at six years when considering acetabular loosening as the end point. At a mean of 72.1 month-follow-up, 92.4 % of the remaining hips were graded as very good or good while 44.6 % showed radiolucent lines around the socket and 4 had migrated with no radio-clinical correlation. On the femoral side, there was no radiolucent line nor loosening, and the value of the colar calcar resorption was low (mean 0.4 mm). In all four revisions, the stem was left in place, and there was no bone loss, which allowed simple revisions. DISCUSSION: Thin radiolucent lines around bulk alumina press-fit sockets can be understood as a normal bone reaction to material as the Young's modulus is much higher. They do not necessarily signify mechanical failure of the fixation. However when considering the rate of acetabular loosening, an improvement of the alumina/bone interface is still required.

Adult↗

PubMed1999

Osteogenesis with coral is increased by BMP and BMC in a rat cranioplasty.

Autologous bone marrow cells (BMC), bone morphogenetic protein (BMP) and natural coral exoskeleton (CC) were used to enhance the repair of large skull bone defects in a craniotomy model. Nine millimeter calvarial defects were created in adult rats and were either left empty (control defects) or implanted with CC alone, CC-BMC, CC-BMP, or CC-BMC-BMP. After 1 or 2 months, osteogenesis was insufficient to allow union when defects were left empty or filled with CC. Addition of BMC alone to CC had no positive influence on osteogenesis at any time and increased CC resorption at 2 months (0.1 +/- 0.1 mm2 versus 0.5 +/- 0.3 mm2). In contrast addition of BM P or BM P/BMC to CC led to a significant increase in osteogenesis and allowed bone union after 1 month. At 2 months, the combination of CC-BM P-BMC was the most potent activator of osteogenesis. Filling a defect with CC-BMP-BMC resulted in significantly increased bone surface area (11 +/- 2.7 mm2) in comparison to filling a defect with CC-BMP (7.0 +/- 1.4 mm2), CC-BMC (3.5 +/- 1.1 mm2) or CC (4.5 +/- 0.4 mm2). CC resorption was significantly decreased in the presence of BMP with or without BMC at both times. These data are in accordance with the presence of progenitor cells in bone marrow that are inducible by BMP to the osteogenic pathway in a cranial site. The increase in material resorption in defects filled with CC-BMC could suggest that cells from the granulocyte-macrophage lineage survived the grafting procedure and were still active after 2 months.

Analysis of Variance↗

PubMed1999

Effects of chitosan on rat knee cartilages.

The aim of this work is to study the effects of chitosan on rat knee cartilages. 0.2 ml of 0.1% chitosan solution pH = 6.9 were injected inside rat knees articular cavity. One, three and six weeks after injection, histological and histomorphometric studies were performed on undecalcified samples embedded in polymethylmetacrylate. Results show that after 1 and 6 weeks: (i) chitosan slows significantly (P < 0.005) the decrease in epiphyseal cartilage thicknesses and (ii) increases significantly articular cartilage chondrocyte densities (P < 0.002). However chitosan solution induces a proliferation of fibrous tissue with abundant fibroblasts, fibrocytes and monocytes inside the joint and this proliferation is still present after 6 weeks. This study suggests that chitosan could act on the growth of epiphyseal cartilage and wound healing of articular cartilage.

Animals↗

PubMed1999

Cementless bulk alumina socket: preliminary results at 6 years.

To avoid polyethylene wear observed in total hip replacement, an alumina-alumina combination has been used since 1977. The aim of this study is to report the results of a hybrid alumina-alumina total hip arthroplasty with a cementless press-fit bulk alumina socket and a cemented titanium alloy stem in 55 patients (62 hips) operated on between 1982 and 1990. The bearing surfaces were a 32-mm alumina head articulating within the alumina socket. Four failures occurred: 3 aseptic loosenings of the socket and 1 femoral head fracture. Considering aseptic loosening as the endpoint, the survival rate was 93.2% after 6 years. At a mean of 72.1 months' follow-up, 92.4% of the surviving hips were graded as very good or good using the Merle d'Aubigné-Postel hip score. Radiolucent lines were observed on the acetabular side in 68.1 of the hips. The future of this interface, which is probably fibrous, remains questionable. With the exception of 1 femoral head fracture, all revisions were related to failure of the bony fixation of the socket, and no problem was encountered related to the alumina-alumina friction coupling. Alumina sockets with other types of cementless fixation have therefore been designed and are presently under clinical investigation.

Adult↗

PubMed1999

Coral grafting supplemented with bone marrow.

Limited success in regenerating large bone defects has been achieved by bridging them with osteoconductive materials. These substitutes lack the osteogenic and osteoinductive properties of bone autograft. A direct approach would be to stimulate osteogenesis in these biomaterials by the addition of fresh bone-marrow cells (BMC). We therefore created osteoperiosteal gaps 2 cm wide in the ulna of adult rabbits and either bridged them with coral alone (CC), coral supplemented with BMC, or left them empty. Coral was chosen as a scaffold because of its good biocompatibility and resorbability. In osteoperiosteal gaps bridged with coral only, the coral was invaded chiefly by fibrous tissue. It was insufficient to produce union after two months. In defects filled with coral and BMC an increase in osteogenesis was observed and the bone surface area was significantly higher compared with defects filled with coral alone. Bony union occurred in six out of six defects filled with coral and BMC after two months. An increase in the resorption of coral was also observed, suggesting that resorbing cells or their progenitors were present in bone marrow and survived the grafting procedure. Our findings have shown that supplementation of coral with BMC increased both the resorption of material and osteogenesis in defects of a clinical significance.

Animals↗

PubMed1999

Complete traumatic brachial plexus palsy. Treatment and outcome after repair.

Seventy-eight patients who had a complete brachial plexus palsy caused by a stretching injury were operated on by the same surgeon between January 1980 and December 1991. The aim of the operative intervention was to obtain the best functional result, including at the level of the hand, that was possible in view of the initial lesions and the intraoperative findings. Therefore, the treatment strategy included not only nerve repair with grafting (124 grafts) or nerve transfer (twenty-seven transfers) but also palliative procedures, the latter of which sometimes were performed several years later. Sixty-three patients were evaluated by an independent observer at least three years postoperatively. The results associated with each type of lesion and each type of nerve repair were assessed according to the function of the muscles that were innervated by the recipient nerve. Six patients had a neurolysis only. The remaining fifty-seven patients had grafts or nerve transfers to repair the biceps. Thirty-six of the fifty-seven received a rating of 3+ or more (meaning that the patient was able to flex the elbow repeatedly); the remaining twenty-one received a rating of 3 or less (meaning that the patient was able to flex the elbow only once or not at all), which we considered unsatisfactory. The function of the triceps recovered after eleven of thirty-one procedures that were performed to restore that nerve; that of the extensor carpi radialis, after five of thirty-one procedures; that of the flexor carpi radialis, after six of thirty-one procedures; and that of the flexor digitorum, after four of thirty-one procedures. A statistical analysis revealed that an operative delay of less than six months was a significant factor with respect to recovery of the function of the biceps (p = 0.003). The thirty-nine grafts that were sutured onto the lateral or posterior cord produced better results than did the thirty-six that were sutured onto the distal branches (the musculocutaneous and radial nerves); however, with the numbers available, this difference was not found to be significant (p = 0.08). Eleven patients had a successful result (a rating of 3+ or more) and eight, a fair or poor result, with respect to recovery of biceps function after transfer of the spinal accessory nerve to the musculocutaneous nerve. Overall, twenty-nine patients had relief of pain postoperatively. Sixteen patients had grade-3 pain preoperatively compared with only three after the operation. According to a self-rating scale, twenty-five patients were satisfied with the overall result, sixteen were fairly satisfied, and twenty-two were dissatisfied.

Adult↗

PubMed1999

[Biomaterials and the living system].

Biomaterials, whatever their applications: cardiovascular surgery, orthopaedic surgery, ophthalmology, plastic surgery, urology, membranes for renal dialysis have some common approach. It is a very interdisciplinary field that needs intervening bioengineers, M.D, biologists and materials scientists. It is a domain with special emphasis on responsability because of the very severe consequence of these material failures. After an overview of these materials and their applications, we will briefly present here the evaluation systems of these biomaterials, including laboratory tests, mechanical tests as well as biological ones. Then we will project in the future to insist on three main orientations: tissue engineering, optimised materials for some precise function and also how new techniques of applied genetic could modify this field in deep in the future.

Biocompatible Materials↗

PubMed1999

Joint diseases.

Explore the source record for details and available documents.

Arthroplasty, Replacement↗

PubMed1998

Addition of fibrin sealant to ceramic promotes bone repair: long-term study in rabbit femoral defect model.

Despite their impact on the healing of soft connective tissue, fibrin sealants have not been shown conclusively to have an important role in the healing of bone defects. We report the positive influence of fibrin sealants on repair of cancellous bone cavities filled with a porous, resorbable ceramic. We studied two fibrin sealants: Autocolle and Tissucol. Autocolle is enriched in platelet factors during its preparation. Tissucol is a commercially available fibrin glue prepared from pooled human plasma that has no enrichment in platelet factors. Cavities 10 mm in depth and 5 mm in diameter were drilled in lateral condyles of 45 New Zealand rabbits. These defects were filled with either coral granules or a mixture of fibrin sealant (Autocolle or Tissucol) and coral granules or left empty. At 1 month addition of a fibrin sealant (Autocolle or Tissucol) to the coral led to a significant increase in bone formation in comparison to coral alone. At 2 months significant fibrin sealant mediated enhancement of bone repair was observed with Autocolle only. At 6 months bone formation was similar to the adult bone amount in nonoperated animals, whatever the initial material. Control cavities, on the other hand, were invaded with fibrous tissue only at each time period.

Animals↗

PubMed1998

Cytokine release from marrow mononuclear cells is negatively correlated to cortical elasticity in non-osteoporotic postmenopausal women.

Activation of bone remodeling is likely to be under the control of mechanical factors acting, in part, through soluble local factors. We therefore investigated a relationship between cytokine production by marrow cells and bone elasticity. We studied 36 non-osteoporotic postmenopausal women undergoing hip arthroplasty for hip arthrosis (mean age: 68 +/- 8 years; lumbar BMD Z-score: +0.54 +/- 0.33 SD). Adherent marrow mononuclear cells were cultured for 48 hours with autologous plasma, and supernatants were harvested for PGE2, IL-1, TNF-alpha, and IL-6 measurements. Femoral neck cortical bones were removed during surgery for cortical histomorphometric evaluation and determination of elasticity indices (C33) using ultrasonic transmission method. In this nonosteoporotic population, femoral neck longitudinal elasticity indices were inversely correlated to both cortical thickness (r = -0.58, P < 0.01) and cortical porosity (r = -0.33, P < 0.01). The longitudinal elasticity indices were also negatively correlated to basal IL-1 and TNF-alpha release by adherent mononuclear marrow cells (r = -0.59, P < 0.01; r = -0.60, P < 0.01, respectively). However, no relationship was found between the three cytokines tested and either cortical thickness or porosity. These data show a link between cortical biomechanical properties and local factors involved in bone remodeling. We suggest that increased bone elasticity decreases transmission of strain, which in turn decreases cytokine release from marrow cells. However, whether cytokines influence bone elasticity or vice versa remains to be demonstrated.

Aged↗

PubMed1998

Femoral head osteonecrosis after bone marrow transplantation.

Thirty-five patients with bilateral osteonecrosis of the femoral head after bone marrow transplantation were reviewed retrospectively. The median age at the time of transplantation was 26 years. The first symptoms occurred within 2 years of transplantation. At presentation, 18 of the patients reported pain in both hips, 17 had symmetric radiographic lesions, and 39 of the hips had collapsed. Medical treatment was indicated initially. At the final examination before surgery (median, 3.5 years), 31 patients had bilateral hip pain, 22 patients had symmetric radiographic lesions, and 56 of the hips had collapsed. Fifty-seven of the hips required surgery, including one open drainage, four core decompressions, six cup arthroplasties, and 46 primary total hip replacements. Six hips (four core decompressions; two cups) later underwent total hip replacement revision, and a deep infection developed in one. By considering the requirement of a total hip replacement as a failure of conservative treatment, the rate of survival of the femoral head was 30% 5 years after the transplant. There was no significant difference between the Ficat grades, except for Grade 0, which showed a higher survival rate. The study of the specific features of the osteonecrosis may lead to the recommendation of primary total hip arthroplasty after failure of the medical treatment.

Adolescent↗

PubMed1998

Massive osteolysis after ceramic on ceramic total hip arthroplasty.

Explore the source record for details and available documents.

Ceramics↗

PubMed1998

[Peptostreptococcus magnus osteoarticular infections after orthopedic surgery. 14 cases and pathogenicity factors].

We report a retrospective study of 14 Peptostreptococcus magnus bone and joint infections, following orthopaedic prostheses or implantation of fixation devices, diagnosed in two Paris hospitals between 1992 and 1996. Five patients experienced a knee joint infection after anterior cruciate ligament reconstruction with 4 artificial grafts, and 9 caught joint or wound infections, after limb traumatic injuries or bone neoplastic ruptures involving femur, tibia, calcaneum and humerus, treated by arthroplasty or osteosynthesis with implantation of biomaterials. Septic arthritis was experienced one week to one year after reconstructive surgery, and had evolved for several months to years before etiologic diagnosis in 5 cases. Specimens of pus, tissues or removed implants produced numerous slow growing small colonies of Gram positive cocci arranged in clumps on culture media incubated in anaerobic atmosphere only. In 10 patients, the same organism was disclosed in several separate specimens. The identification of P. magnus was assessed by the enzyme profile (rapid ID 32A API strips), gaz liquid chromatography, catalase and coagulase production, resistance to novobiocin and Na polyanethol sulphonate. Antibiotic sensitivity testing performed by disc method was constant to penicillin G, amoxicillin, cefuroxime, cefoxitin, imipenem and pristinamycin with penicillin G MICs < 0.125 mg/l and metronidazole MICs < 1 mg/l. Erythromycin, clindamycin, rifampicin, tetracycline and fosfomycin were active against more than 70% of P. magnus. All patients were cured after a prolonged course of various antibiotics and surgical removal of the foreign material whenever possible. We studied in vitro binding of P. magnus with extracellular matrix proteins adsorbed onto biomaterials, by particle agglutination assays of latex beads coated with proteins. Eighty one% of strains bound to collagen, 69% to fibrinogen and 46% to fibronectin. Comparison of orthopaedic strains with strains of other infections and from skin showed a correlation between P. magnus from bone and joint infections and their fibrinogen binding ability (69% against 20%, p < 0.05).

Adolescent↗