Bioceramics 17

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Authors: Simeon Agathopoulos, M. Nedea, Brandusa Ghiban, José Maria F. Ferreira, P. Nikolopoulos
Abstract: The surface energy components which govern the interfacial interactions between bioinert solid substrates of partial stabilized ZrO2 (with 3 mol% Y2O3) and a glass with a composition of 55SiO2×10Na2O×35MgO in contact with organic and biological liquids under equilibrium regime, were determined. The experimental results indicated that the interfacial bonding between zirconia and the polar liquids is result of interactions due to dispersion forces. In the case of the glass, polar forces significantly contribute to solid/liquid interfacial interactions.
1023
Authors: Thomas Oberbach, Marita Christoph, Wilfried Glien
Abstract: Alumina and zirconia have played an important role in joint endoprosthetics for the use in tribologically loaded implant components like hip joint heads and cups for years. In our investigations we prepared an alumina ceramic with a gradient in concentration of zirconia. The zirconia content was realized by infiltration processes with different ZrO2 – precursors. The material was characterized concerning ZrO2-distribution, infiltration depth and microstructure.
1027
Authors: Juan C. Hermida, Darryl D. D'Lima, Nikolai Steklov, Clifford W. Colwell
Abstract: Hydroxyapatite (HA) coatings for femoral stems have been successful in short- to intermediate-term follow up. However, the outcomes of HA-coated cups have not been as successful as comparable non-HA-coated designs. This has been attributed to component design and to poor quality HA-coating processes. This is a clinical outcome study of a newer generation acetabular design with an improved plasma-sprayed HA-coat. Ninety consecutive primary total hip replacements implanted with a HA-coated metal-backed cup were prospectively followed up for 2–5 years after surgery. Mean age was 69 years, male:female ratio was 36:47; mean-weight was 77 kg. Polyethylene wear was measured on digitized images. Component position, component migration, and implant-bone interface radiolucent lines were analyzed by computerized image analysis. Hip-scores improved from preoperative mean 59(±12) to a final follow-up mean of 91(±12). One hip was revised for recurrent dislocation. No hips were revised for aseptic loosening. Mean acetabular abduction angle was 46°(±8.5) and anteversion was 18°(±8.7). Incomplete lucent lines were noted on early postoperative radiographs in 5% of the cases. With ongoing follow up radiolucent line thickness decreased by mean 13% and radiolucent line density increased by 11%. No cup had complete continuous radiolucent lines or lysis. Mean polyethylene linear and volumetric wear rates were 0.14(± 0.15) mm/year and 73(± 70) mm3/year respectively. Wear rates were higher in males (p<0.03). No other factor (age, body weight, cup abduction or anteversion angle) correlated significantly with wear rate. This study presents encouraging short-term results. The improvement in radiolucent lines suggests a beneficial effect of the HA-coat on bone ingrowth. None of the cups loosened or migrated. Wear rates were comparable to published reports of successful non-HA-coated cups. Long-term follow up is ongoing to corroborate these early findings.
1033
Authors: A. Moroni, C. Faldini, F. Pegreffi, A. Hoang-Kim, F. Vannini, S. Giannini
Abstract: External fixation has proven to be a viable minimally invasive treatment option for elderly patients with trochanteric fractures. Postoperative complications has limited external fixation in relation to inadequate pin fixation. We compared Orthofix pertrochanteric fixator (OPF) with hydroxyapatite-coated pins to dynamic hip screw (DHS) with AO/ASIF stainless-steel screws in osteoporotic trochanteric fractures. Methods: Forty patients were divided into two groups and randomized for treatment with 135° 4-hole DHS (Group A) or OPF with four hydroxyapatite-coated pins (Group B). Inclusion criteria was: female, age ≥ 65 years, AO fracture type A1 or A2 and BMD lower than -2.5 T-score. All fixators were removed at 3 months. Results: There were no differences in patient age, fracture type, BMD, ASA, hospital stay and reduction quality. Average number of blood transfusions was 2.0 ± 0.1 in Group A, whereas there were none in Group B (p < 0.0001). Operative time was 64 ± 6 minutes in Group A and 34 ± 5 in Group B (p < 0.005). Post-operative femoral neck shaft angle was 134 ± 6° in Group A, and 132 ± 4° in Group B (ns). In Group A, fracture varization at 6 months was 6 ± 8°, in Group B 2 ± 1° (p = 0.002). Harris hip score was 62 ± 20 in Group A and 63 ± 17 in Group B. (n.s.) In Group B, no pin infection occurred. Pin fixation was maintained over time, as shown by no significant difference between pin extraction and corresponding insertion torque. Discussion and Conclusion: In external fixation with hydroxyapatite-coated pins there was no need for blood transfusions and fixation was superior, as confirmed by less varization at long-term.
1037
Authors: M. Gutierres, Nandyala Sooraj Hussain, A. Afonso, L. Almeida, T. Cabral, M.A. Lopes, José D. Santos
Abstract: This paper reports the ability of Bonelike® to regenerate bone defected areas when implanted in the tibia of 3 patients (average age of 59 years) during a high tibial osteotomy (HTO) to treat medial compartment osteoarthritis of the knee. Bonelike® is a synthetic bone graft designed to mimic the inorganic composition of bone using a patent process that consists of liquid sintering hydroxyapatite in the presence of CaO-P2O5 based glass. The preliminary clinical evaluation performed showed that an intimate contact between new formed bone and Bonelike® was established (67±10 %), with no fibrous interface. Therefore, Bonelike® is a single-handedly viable osteoconductive synthetic grafting material as it has been demonstrated from the profiles of radiological, histological and scanning electron microscopy analyses for the six months implantation period.
1041
Authors: James M. Buchanan
Abstract: Traditionally implants for hip arthroplasty are secured with bone cement. Problems have been encountered with cement fixation with loosening and osteolysis attributed to the reaction to particulate cement material and also polyethylene debris from wear. Cementing techniques have been improved and the Swedish Hip Register [1] demonstrates that the revision rates have been reduced with improved cementing techniques. However, uncemented hip arthroplasty is now having a revival. In particular, bioactive materials are being used and this paper presents the results of a consecutive series of hip arthroplasties carried out over a total period of just 16 years. All the patients are included, including primary and revision hip arthroplasty. Patients are assessed using the Harris Hip Score [2]. 13% of the hips scored less than 80 on the Harris Hip Score but only 9.4% scored poor pain scores. These represent the results of poor hip arthroplasty, of which an even smaller percentage are related to failed HA hip arthroplasty.
1049
Authors: Pierre Weiss, Léon Philippe Clergeau, Bénédicte Enckel, Yves Amouriq, Bernard Giumelli, Alain Jean, G. Daculsi
Abstract: For the first time, an injectable bone substitute (IBS) made of a suspension of Calcium phosphate ceramic was used in a clinical trial in human after extraction of non conservable tooth (36 or 46). 11 patients did agree for implantation of their sockets with the biomaterial. It was an explorative study and the results showed no pain due to the biomaterial implantation, no infection, no inflammation and perfect biocompatibility. The safety and the bioactivity of this concept of biomaterial were confirmed in human implantation after several animals’ pre-clinical studies.
1053
Authors: Takafumi Yoshikawa, Y. Ueda, Takahito Ohmura, Yasunori Sen, Jin Iida, M. Koizumi, Kazuhide Miyazaki, Yoshinori Takakura, Akitaka Nonomura
Abstract: Subjects were graft patients with pseudoarthrosis (average age, 60.3 years; range, 17-85 years). Pseudoarthrosis affected the thoracolumbar spine, the femur, the clavicle, the humerus and the metatarsal. From the ilium (tibia in one patient), 10-20 ml of bone marrow fluid was collected, and then, it was immediately transferred to the culture room and incubated in a flask containing MEM with 15% autologous or fetal bovine serum, etc.. After 2 weeks in primary culture, cells were released by trypsin treatment and were subsequently incubated with porous beta-TCP in order to prepare tissue-engineered artificial bone, according to the previously reported modified culturing technique. Tissue-engineered artificial bone was grafted around the non-union site of each affected long bone, while tissue-engineered artificial bone was grafted via the pedicle of each affected vertebral body. In all patients, favorable bone formation was seen at three months after surgery. In the patients with pseudoarthrosis of the spine, CT and MRI confirmed favorable vertebral body formation. In the patients with pseudoarthrosis of a long bone, the artificial bone was remodeled and favorable bone union was confirmed. In 2 patients in whom bone biopsy was performed during pin removal, bone regeneration was confirmed histologically. With present type of tissue-engineered artificial bone, an artificial material with a high bone regeneration capacity can be prepared by aspiration, which is minimally invasive, and thus when compared to iliac bone grafts, it is possible to radically reduce postoperative pain without damage of autologous bone.
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