The use of a total hip arthroplasty with alumina on alumina bearing couple should limit the risk of wear and secondary osteolysis. From June 1999 to December 2002, we have realised a continuous series of 265 ABGII cementless THA with Alumina bearing. The average age was 58 years (22–78 years). The main causes were osteoarthritis (81%) and osteonecrosis (13%). The operation was performed through a posterior standard approach. In all cases, an anatomic cementless ABG II stem and an acetabular cementless ABG II cup were implanted. The bearing couple was always Alumina Biolox Forte with a 28 mm femoral head in 99% of cases. To date, 12 patients died and 17 patients were lost to follow up (6.4%). 224 patients (232 hips) had a regular clinical and radiological follow-up. The mean follow up was 8.5 years (5–11 years). 9 patients were revised for septic loosening (4cases), femoral fracture (4 cases) and inveterate dislocation (1 case). There was no aseptic loosening. The overall survival rate at more than 10 years is 96.6%. We deplore 2 cases of postoperative dislocation. In this series, we did not observe any breakage of ceramic implant. The clinical and functional outcome is good and stable over time with an average PMA score at 17.6 and an average Harris score at 97.3. 16 patients reported at least one or more episode of abnormal noise “Squeaking” type (6%). It is most often a mild noise and it occurs in a static bending position. This noise disappeared with time in 10 cases. It never necessitated a prosthetic revision. The radiological control does not show any wear. There is no evidence of acetabular or femoral osteolysis. The radiological implant fixation according to the Engh and ARA criteria was good and stable in all cases. This series demonstrate that the implantation of an anatomic cementless HA arthroplasty with an alumina bearing in a young and active patient prevents the risk of wear and osteolysis and improves durability over time. The use of a 28 mm head does not increase the risk of instability and we did not observe failure of the ceramic implants

Introduction. One of the most common complications of ceramic on ceramic hip replacement is squeaking. The association of Accolade stem and Trident acetabular system has been reported to have squeaking incidence of up to 35,6%. There is doubt if this phenomenon occurs due to: the stem titanium alloy, the V40 femoral neck, the recessed liner of the trident cup or even the mal-seating of the trident insert on the cup. Objectives. Primary: The purpose of the present study was to determine the incidence of squeaking in association with the use of Exeter stem and Trident ceramic acetabular system. Secondary: Analysis of the correlation of the cup abduction angle and squeaking. Methods. During the period from March 2004 to December 2008, two surgeons performed 87 total hip arthroplasties in 77 patients with use of a ceramic-on-ceramic bearing (Exeter stem, alumina head, Trident ceramic acetabular system). Seventy six patients (86 THA) were available for review after at least 18 months follow-up. The incidence of squeaking and other noises was analyzed. Cup abduction angle was measured. The Pearson correlation coefficient was used to determine if a correlation existed between the cup abduction angle and squeaking. Results. The incidence of squeaking was 2,63% (2 patients). Both patients reported a “click” noise in hyperextension of the hip. The mean abduction angle was 44 degress (35–60), and 48 degrees (46 and 50) on the squeaking group. There was no statistically significant difference in the in the mean cup inclination between squeaky and quiet hips. Conclusion. The incidence of squeaking in association with the use of Exeter stem and Trident ceramic acetabular system was 2,63%. There was no correlation of the cup abduction angle and squeaking

Aims. Will Hydroxyapatite hip (HA) arthroplasty associated with ceramic bearings produce uncomplicated function in younger, active patients’ The incidence of aseptic loosening, dislocation and broken implants has been particularly investigated. Debris disease from plastic debris contributes to aseptic loosening. Hard-Hard bearings should obviate this problem. Metal-metal will release ions which might be deleterious. Experience with metal-metal resurfacing has high lighted problems including pseudo-tumours. Ceramic bearings may fracture but otherwise appear free of complications. Methods. This is a study extending over 19 years of 626 HA hip arthroplasties with ceramic bearings. Annual review using Harris Hip Score to assess pain and function and X-rays to check osseointegration has been performed. Alumina ceramic was inserted in 467 hips. The newer Zirconia Toughened Alumina (ZTA) has been inserted in 169 hips. There are 118 hips still under review at 10 or more years. Results. Aseptic loosening is unusual (one stem, two acetabulae (3 of 1252 components, 0.24%) Failure from mal-orientation with repeated dislocation occurred in six hips (0.96%). Three alumina heads (0.48%) and two alumina liners (0.32%) broke. There has been no failure of ZTA ceramic. No patients have thigh pain. Osteolysis and debris disease have not arisen. Harris Hip Scores show 91.2% scoring over 90 or 100. Lower scores mostly relate to other joint and medical problems. Conclusions. Assessments confirm that patients remain well. Aseptic loosening of HA hips is rare at 0.24%. Failure from broken alumina components is unusual. Alumina has now been superseded by ZTA for implantation. Ceramic on ceramic is a reliable selection for bearing surfaces in patients of any age and either sex

Introduction. In total hip arthroplasty ceramic on ceramic bearing couples are used more and more frequently and on a wordwide basis. The main reason of this choice is reduction of wear debris and osteolysis. The tribological properties and the mechanical behaviour of the implanted ceramic must remain the same throughout the patient's life. The aim of this study was to evaluate the resistance of Alumina Matrix Composite to environmental degradation. Material and method. The alumina matrix composite or BIOLOX ® delta is manufactured in Germany by CeramTec. It is made up of 80 vol.% Al2O3, 17 vol.% Yttria Stabilized ZrO2 and 3vol.% strontium aluminate platelets. The zirconia grains account for 1.3 mol.% of the Yttria content. Accelerated aging tests in water steam at 142°C, 134°C, 121°C, and 105°C were performed to evaluate the aging kinetics of the composite. X-ray diffraction was used to determine the monoclinic phase content on the material surface. Phase transformation is associated with weakness and increase in roughness of zirconia ceramic implants. Results. The data below shows average monoclinic contents before and after aging in water vapour according to the ISO standard test (134°C, 2 bars water steam, 10 h) on the surface and inside the 28 mm taper(12/14 taper) femoral ball heads manufactured in alumina ceramic composite. There are precisions concerning the roughness and the load to failure before and after aging concerning 28mm diameter heads. Before Aging 13%+/-3% of Monoclinic content. After 10 H at 134°C23%+/-3% of Monoclinic content the roughness of the polished surface remain the same (5nm+/− 2). The load to failure of 28 mm heads before aging is 76 kN +/− 5kN, and 72 kN +/− 5kN after aging. The results show that although a rise in monoclinic content is predictable after long aging duration in vivo, the impact of the transformation is quite different to monolithic zirconia. A zirconia femoral head exhibits an important increase of roughness from 2 nm to more than 50 nm when submitted to the same duration of ageing. Other tests with hip simulators under severe micro separation have been done to analyse the impact of aging on wear performance. The main wear zone on femoral heads underwent a phase transformation from tetragonal to monoclinic (23% monoclinic) at 5 milion cycles duration without any change in roughness after 5Mc duration. Conclusion. This experimental testing program has enabled a prediction for the long-term in vivo environmental resistance of prostheses made out of Alumina Matrix Composite. The substantial improvement in mechanical properties and the excellent wear behaviour, even under severe microseparation conditions has been clinically confirmed. Today more than 960,000 ceramic ball heads and more than 450 000 ceramic inserts made of the alumina matrix composite have been implanted. Additionally, due to enhanced mechanical behaviour, new applications in orthopaedics are possible

In biomaterial engineering the surface of an implant can influence cell differentiation, adhesion and affinity towards the implant. Increased bone marrow derived mesenchymal stromal cell (BMSC) differentiation towards bone forming osteoblasts, on contact with an implant, can improve osteointegration. The process of micropatterning has been shown to improve osteointegration in polymers, but there are few reports surrounding ceramics. The purpose of this study was to establish a co-culture of BMSCs with osteoclast progenitor cells and to observe the response to micropatterned zirconia toughened alumina (ZTA) ceramics with 30 µm diameter pits. The aim was to establish if the pits were specifically bioactive towards osteogenesis or were generally bioactive and would also stimulate osteoclastogenesis that could potentially lead to osteolysis. We demonstrate specific bioactivity of micropits towards osteogenesis with more nodule formation and less osteoclastogenesis. This may have a role when designing ceramic orthopaedic implants

In a randomized study of 60 patients allergic reactions are evaluated in three joint prosthesis groups, a resurfacing arthroplasty (ReCap), a non-cemented, large metal-on-metal head (Bimetric Magnum) and a non-cemented, alumina ceramic-on-ceramic bearing in a titanium shell (Bimetric C2a). The inclusion criteria were osteoarthritis, ASA I–II, MRI-scan without caput necrosis, DXA-scan without osteoporosis. The exclusion criteria were short neck (<2cm.), large cysts (>1cm.), medical treatment affecting the bone metabolism, severe deformity of the femoral head, impaired kidney function and inability to co-operate. Blood samples were drawn prior to and 6 weeks, 6 months, 1 year, and 3 years after surgery; two tubes from which plasma was prepared, and two tubes for serum. From the last included 20 patients in each group was also taken blood one and three years after surgery for an in vitro lymphocyte assay for scoring of possible hypersensitivity to prosthesis metals. The isolated lymphocytes were subjected to measurement of proliferation and expression of CD69 by flow cytometry and measurement of the Migration Inhibitory Factor (MIF) by ELISA. Plasma concentrations of the cytokines IL-1, IL-4, IL-6, IL-8, IL-12p70, IL-15, interferon-and osteoprotegerin were determined by multiplex-immunoassay. Serum concentrations of chromium and cobalt were determined by graphite furnace atomic absorption spectrometry. The serum concentrations of chromium and cobalt were lowest in patients with the C2a implant and highest with Magnum, some of these differences were significant at 6 weeks, 6 months, and 1 year after surgery. No patient had a very high serum metal concentration. The values of the variables measured in the in vitro lymphocyte assay mainly changed in the expected direction depending on the concentration of the same metal in the serum sample drawn at the same time, but no significant correlation was seen. One patient had uncertain symptoms of metal hypersensitivity and relatively high serum metal concentrations 3 years after arthroplasty with a Magnum prosthesis and was assessed extraordinarily, and elicited the marginally highest MIF responses in the lymphocyte assay. A strong correlation was found between the plasma concentrations of most cytokines, but the cytokine concentrations were not correlated to contemporary metal concentrations

Cemented total hip arthroplasty yields reliable results in short to medium term studies, but aseptic loosening remains a problem in long-term follow up, especially in young and active patients. Aseptic loosening has been related to wear, and in order to minimize wear various alternatives to the traditional metal on polyethylene have been proposed. Both ceramic on polyethylene (COP) and metal on metal (MOM) have been shown to produce less wear than metal on polyethylene (MOP). In order to study the effect of the bearing, we have utilized identical stems and cups while comparing the different bearings. Methods and material. 396 hips were randomized to MOP, COP or MOM using a cemented triple tapered polished stem (MS-30; Sulzer Orthopedics) with a cemented polyethylene cup (Weber; Sulzer, Orthopedics) and a 28 millimeter head. For the MOP and COP articulations, a all-polyethylene cup was used with a Protasul™ metal head or a Sulox™ alumina head, whereas a polyethylene cup with metal insert was used for the MOM articulations (Weber Polyethylene Cup with Metasul™ Insert) with a Metasul™ metal head. Harris Hip Score (HHS) and radiological evaluation was performed after two, five and seven years. Ethical approval was obtained. Results. HHS was available for 338 hips after seven years. The HHS in the MOP group (116 hips) was 93.7 (SD 9.0), 93.5 in the COP group (112 hips) (SD 8.8), and 91.0 (SD 13.4) in the MOM group (110 hips). Radiographic evaluation was available for 335 hips. Radiolucencies around the stem larger than one millimeter were found in five of 115 MOP hips, seven of 111 COP hips and in seven of 110 MOM hips. Periacetabular radiolucencies identified as larger than one millimeter were found in none of the 116 MOP hips, five of the 112 COP hips and in 19 of the 110 MOM hips. Ten revisions were performed. In the MOP group there were three revisions (infection, dislocation, pain); one in the COM group (infection), and six in the MOM group (three infections, two aseptic loosening and one septic loosening). Discussion. Clinically, the three bearing types perform equally well at seven years, and there are few signs of impending failure for the stem. However, there are an alarmingly high proportion of cups showing signs of loosening. Two hips have been revised in the MOM group for aseptic loosening as opposed to none in the two other groups, which adds to the concern. The MOM articulation used in this study should be monitored closely for signs of aseptic loosening

Introduction. In knee arthroplasty a ceramic component has several advantages: first, there is no ion release implying a risk for potential allergies. Second, the hardness of the material leads to a scratch resistance which ultimately reduces PE wear over time. In the past, ceramic components in knee applications were limited in the variety of design possibilities due to necessary thickness of the component resulting from the associated fracture risk of ceramics. By the development of an alumina matrix composite material with increased mechanical properties it is possible to develop ceramic knee components which have nearly the same design as a metal component and use the same implantation technique as well as the same instruments. This offers the surgeon the opportunity to choose intraoperatively between metal or ceramic knee components. Extensive in-vitro testing shows that ceramic knee components achieve superior mechanical test results. The reliability of the components is proven by two different burst tests and a fatigue test for both a femoral and a tibial ceramic knee component. Material and method. The mechanical proof-test was developed by subsequent steps of numerical load/stress analysis and design of an adequate mechanical test equipment. The procedure was organized as follows:. Oncologic: Analysis of relevant maximum in-vivo loading conditions. Analysis of the “boundary conditions”. Finite Element analysis: Identifying regions of highest stress concentration. Design analysis and accommodation if necessary. Development of an adequate mechanical test equipment which produces stresses comparable to the in-vivo conditions. Performing mechanical tests with ceramic femoral components. Validation of the test concept: comparison of test results and stress analysis. Assign “safety margin”,. Establish “proof test”. Results. Two independent load scenarios have been determined for each type of components as being in-vivo relevant. Hence, the developed proof-test consists of two subsequent load tests, the so-called regular test and the tension test for the femoral components, and the upper side test and the lower side test for the tibial components. In the regular test, the mechanical strength of the polished outer condyles is tested using a force which is equivalent to an in-vivo loading of 16 times bodyweight. In the tension test, the interior sides of the condyles are stressed in the sagittal plane ensuring a mechanically reliable implantation. This test is performed with a force equivalent to 10 times bodyweight. Discussion. The procedure to determine the proof loads using the maximum in-vivo loads together with a safety factor ensures the mechanical safety of the ceramic knee component. Together with the well-known excellent wear and biological behaviour of ceramics, this application provides an alternative to common metallic knee components. Clinical observations in the framework of a multi-centre study in different European countries have been started and show very promising results