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Sodium titanate formed on Ti metal by NaOH and heat treatments induces apatite formation on its surface in a body environment and bonds to living bone. These treatments have been applied to porous Ti metal in artificial hip joints, and have been used clinically in Japan since 2007. Calcium titanate formed on Ti-15Zr-4Nb-4Ta alloy by NaOH, CaCl2, heat, and water treatments induces apatite formation on its surface in a body environment. Titanium oxide formed on porous Ti metal by NaOH, HCl, and heat treatments exhibits osteoinductivity as well as osteoconductivity. This is now under clinical tests for application to a spinal fusion device. [ABSTRACT FROM AUTHOR]

Abstract: The effective life of artificial joints is approximately 15 years and it is necessary to extend this effective life. Previously, the use of graft-polymerized 2-methacryloyloxyethyl phosphorylcholine (MPC) was proposed for this purpose. However, the mechanism underlying the wear reduction in ultra-high molecular weight polythene (UHMWPE) by hydrophilic polymers such as MPC polymers remains unexplained. Therefore, this study investigates the characteristics of the MPC polymer membrane grafted onto the surface of a UHMWPE plate. The investigation clearly revealed that the MPC polymer membrane has a finely porous inner structure with a diameter of approximately 100nm, and hence the membrane has a high water-retention capacity. Furthermore, a 2-axis pin-on-plate sliding test of a UHMWPE pin sample with an MPC polymer grafted on its surface revealed that the water-retention capacity of the porous MPC membrane plays an important role in wear reduction. [Copyright &y& Elsevier]

Novel ultra-high molecular weight polyethylene (UHMWPE)/zirconia composites were previously prepared by the in situ polymerization of ethylene using a Ti-based Ziegler-Natta catalyst supported on to the surface of zirconia, as a bearing material for artificial joints. Tribological tests revealed that a uniform dispersion of zirconia in UHMWPE markedly increased the wear resistance. The effects of zirconia content on the oxidation behavior of the γ-ray-treated UHMWPE/zirconia composite surfaces were examined. The oxidation index that estimates the oxidation degree as the content of total carbonyl compounds was monitored using Fourier transform infrared spectroscopy-attenuated total reflectance. The changes in the surface composition due to the oxidation were confirmed by electron spectroscopy for chemical analysis. The extent of oxidation decreased with increasing zirconia content, which was attributed to the increased crystallinity as well as the decreased polymer portion of the UHMWPE/zirconia composites. [ABSTRACT FROM AUTHOR]

Crevices of artificial joints can become occluded and are prone to severe corrosion. Different crevice width was controlled to reveal its effect to corrosion for two commonly used alloys (316L stainless steel and CoCrMo alloy). The results show that 316L stainless steel with the narrowest (0.05 mm) width corrodes more easily and more severely. There is no typical crevice corrosion for CoCrMo alloy, and the exterior of the crevice has different degrees of corrosion due to the mass transfer effect caused by the crevice with different widths. The corrosion rate reaches the lowest value when the width is 0.1 mm. [Display omitted] • 316L suffers serious corrosion under crevice width between 0.05 mm and 0.1 mm. • Corrosion occurs outside crevice region for CoCrMo due to mass transfer. • Outside crevice for CoCrMo, corrosion shows a gradient behaviour. [ABSTRACT FROM AUTHOR]

In order to provide anatomical basis for transoral approach (TOA) in dealing with the ventro lesions of craniocervical junction, and the design and application of artificial atlanto-odontoid joint, microsurgical dissecting was performed on 8 fresh craniocervical specimens layer by layer through transoropharyngeal approach. The stratification of posterior pharyngeal wall, course of vertebral artery, adjacent relationship of atlas and axis and correlative anatomical parameters of replacement of artificial atlanto-odontoid joint were observed. Besides, 32 sets of atlanto-axial joint in adults’ fresh bony specimens were measured with a digital caliper and a goniometer, including the width of bony window of anterior arch of atlas, the width of bony window of axis vertebra, the distance between superior and inferior two atlas screw inserting points, the distance between two axis screw inserting points etc. It was found that the width of atlas and axis which could be exposed were 40.2±3.5 mm and 39.3±3.7 mm respectively. The width and height of posterior pharyngeal wall which could be exposed were 40.1±5.2 mm and 50.2±4.6 mm respectively. The distance between superior and inferior two atlas screw inserting points was 28.0±2.9 mm and 24.0±3.5 mm respectively, and the distance of bilateral axis screw inserting points was 18.0±1.2 mm. The operative exposure position through TOA ranged from inferior part of the clivus to the superior part of the C3 vertebral body. Posterior pharyngeal wall consisted of 5 layers and two interspaces: mucosa, submucosa, superficial muscular layer, anterior fascia of vertebrae, anterior muscular layer of vertebrae and posterior interspace of pharynx, anterior interspace of vertebrae. This study revealed that it had the advantages of short operative distance, good exposure and sufficient decompression in dealing with the ventro lesions from the upper cervical to the lower clivus through the TOA. The replacement of artificial atlanto-odontoid joint is suitable and feasible. The design of artificial atlanto-odontoid joint should be based on the above data. [ABSTRACT FROM AUTHOR]

Lubrication modelling is of great importance in the design of artificial hip joints, especially for the demand of long life expectancy of those joints employing a metal-on-metal bearing. Through lubrication analysis, the dimensions of the head/cup and the clearance between them can be reasonably determined, and thus, if fluid film lubrication can be generated in artificial hip joint replacements, the wear and related failure can be reduced. In the majority of published numerical studies of the lubrication of hip joints, the synovial fluid for the natural joint and bovine serum used for in vitro simulator testing of joint replacements have always been treated as isoviscous, incompressible Newtonian fluids because the viscosity of these lubricants is almost unchanged at high shear rate. However, all these biological lubricants generally exhibit non-Newtonian characteristics of shear thinning, particularly under relatively low shear rates, and display a second Newtonian plateau at high shear rates. In this paper, model geometry is investigated first to show that the ball-on-plane model is a reasonable approximation to a typical metal-on-metal hip joint bearing considered. Then, in order to accurately predict the film thickness and pressure, the Reynolds equation considering the shear thinning effect of biological lubricants is derived, based on the Rabinowitsch model and following Greenwood's approach. The non-Newtonian effect was considered through two effective flow factors in the sliding and leakage directions, respectively. Numerical simulations were conducted on the basis of an equivalent ball-on-plane model with an effective radius determined from the head radius and the radial clearance, showing the influence of the shear thinning effect. The general lubrication model based on the unified Reynolds equations model was solved for the film thickness and pressure distribution, and the FFT-based approach was utilized to speed up the time-consuming calculation of elastic deformation in a fully numerical lubrication analysis. The results showed that the predicted film thickness when considering the shear thinning effect was slightly larger than that from the isoviscous model. It was found, however, that if the viscosity of the lubricant is adopted as the asymptotic value at high shear rate, the isoviscous Newtonian model can also give accurate predictions of film thickness. This is due to the relatively high shear rate in the contact zone. [ABSTRACT FROM AUTHOR]

Abstract: Surface texture design of a tribo-pair affects its tribological behaviors and temperature distribution, subsequently its performance behaviors and servicing life. Numerical simulation and experiment to study the influence of rectangular texture, on UHMWPE acetabular cup reciprocally slid with steel ball was performed. Results demonstrated the occurrence of periodical and regular fluctuation of the surface temperatures in the cup and ball in accordance with the swing of the ball arm. Higher temperature and amplitude of fluctuation were observed in the ball for cup/steel-ball pairs. Predicted temperature for steel ball sliding in UHMWPE cup with rectangular texture is close and comparable with experimental data under steady state. Prediction reveals that: (i) increase in load and frequency increases the wear depths; (ii) wear of rectangular texture for the condition of short sliding time seems agreeable with experimental data; (iii) thermal effect changes the service performance of UHMWPE after a significant long period of operation that may be explained by the viscoelastic behavior of polymer; and (iv) thermal effect is likely to accelerate the degradation of polymer. [Copyright &y& Elsevier]

Five patients with rheumatoid arthritis or osteoarthrosis of the wrist joint were followed up for 15 (14-17) years after wrist-joint arthroplasty with semiconstrained artificial joint mechanisms that had been anchored to bone using the osseointegration principle. They were fixed by one titanium screw introduced into the radius, and two or more titanium screws introduced distally into the metacarpal bones. In four cases a screw was also introduced into the ulna thereby constituting one component in a distal radio-ulnar (DRU) joint mechanism. The titanium screw introduced into the radius and the distal metacarpal screws osseointegrated in all cases. In three cases the mechanism of the wrist joint or parts of it were replaced with new components that could be attached to the screws that were already osseointegrated. We conclude that wrist joint prostheses can be anchored to the surrounding bone using osseointegration and that they remain fixed for at least 15 years. The principle allows replacement of the joint mechanism, if needed, with maintenance of the osseointegrated anchoring elements. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a new two-step plasma immersion ion implantation technique was developed and applied for the modification of Ti6Al4V alloy; firstly ion implanting with nitrogen at high temperature and followed with oxygen in high dose. A graded titanium oxide–titanium nitride film was obtained on the surface of the Ti6Al4V alloy. The contact angle and the microhardness of the modified alloys were measured. The friction and wear properties of UHMWPE rubbing against the modified alloys under lubrication of distilled water were investigated using a pin-on-disc tribometer. The wettability and the microhardness of the alloy surfaces were found to be increased significantly after ion implantation. The friction coefficient decreased by nearly 5 times and the wear resistance of UHMWPE increased by about 40 times against the ion implanted Ti6Al4V alloy. Many deep furrows were found on the surface of the un-implanted alloy and were absent in the ion implanted surfaces of the alloy. [Copyright &y& Elsevier]

Posts are used in various implant designs to contribute to the short- and long-term fixation stability of artificial joints. This study was undertaken to investigate the effect of torque loading on the pull-out response of a steel post inserted into high-density polyethylene (HDPE) material. An experimental apparatus was designed and fabricated to perform mechanical characterization of a steel post embedded in a polymer cylinder with initial interference fit under pull-out, torque and combined torque/pull-out loadings. To analyze the effect of preload applied torque to the load transfer at the post-fixation interface under pull-out loading, we have chosen HDPE material with uniform mechanical and tribological properties. Under pull-out loading, the micro-slip initiation and propagation at the post-HDPE interface was found to be progressive and assuming Coulomb friction at the interface, the friction coefficient was calculated from the measured pull-out force. In the torque loading condition it was found that the torque dropped suddenly from the maximum value to an initial dynamic sliding torque value. The interface behaves like a chemically bonded one, and static and dynamic friction coefficients were determined. It has been found under combined torque/pull-out conditions that in addition to the reduction of the maximum pull-out force, the preload applied torque generates two instabilities in the pull-out behavior. The first one happens once the maximum pull-out force is reached where the load falls to a level required for the post extraction from the HDPE cylinder. The second instability takes place during the extraction process for a residual (critical) implantation length which depends on the preload applied torque value. This latter instability was marked by a sudden rotation of the HDPE cylinder against the steel post. [ABSTRACT FROM AUTHOR]

Abstract: In order to meet the requirements of customized artificial joint design, and to reduce the production cycle and cost, we present a method to generate the complex surface of an artificial knee joint by co-ordinate measuring machine (CMM) from the normative prosthesis, and form the model data base. First, this paper describes how to plan the measure method to get the better data points and how to deal with the point cloud data. Then, the free-form surfaces are constructed from the point cloud data using the reverse engineering software—Surfacer. Lastly, the solid CAD model of the artificial knee joint is created from the surfaces by extension, intersection and so on. These models formed the data base of the prosthesis, in which we can select a suitable kind of artificial knee joint model to customize for the patient. That is, we only need to change the local data of the corresponding CAD model to meet the different requirements of the patient. [Copyright &y& Elsevier]

Abstract: The artificial joint acetabular material ultrahigh molecular weight polyethylene (UHMWPE) was reinforced with carbon fibers (CF) in different contents. The effects of CF content on hardness and tribological properties of the materials were studied. The morphologies of wear surfaces were examined with a Scanning Electron Microscope (SEM). The results show that the hardness and wear resistance of CF-reinforced UHMWPE composites increased with CF content; the friction coefficients under distilled water lubrication were decreased greatly by the addition of CF; that adherence, plowing, plastic deformation and fatigue wear are dominant for the UHMWPE under dry sliding, and that abrasive wear and drawing out of CF from the wear surface of the composites are dominant for the CF-UHMWPE composites under both dry and distilled water lubrication conditions. [Copyright &y& Elsevier]

While only alumina is applied to all‐ceramic joint prostheses at present, a stronger ceramic is required to prevent fracture and chipping due to impingement and stress concentration. Zirconia could be a potential substitute for alumina because it has high strength and fracture toughness. However, the wear of zirconia/zirconia combination is too high for clinical use. Although some investigations on composite ceramics revealed that mixing of different ceramics was able to improve the mechanical properties of ceramics, there are few reports about wear properties of composite ceramics for joint prosthesis. Since acetabular cup and femoral head of artificial hip joint are finished precisely, they indicate high geometric conformity. Therefore, wear test under flat contact was carried out with an end‐face wear testing apparatus for four kinds of ceramics: alumina monolith, zirconia monolith, alumina‐based composite ceramic, and zirconia based composite ceramic. Mean contact pressure was 10 MPa and sliding velocity was 40 mm/s. The wear test continued for 72 hours and total sliding distance was 10 km. After the test, the wear factor was calculated. Worn surfaces were observed with a scanning electron micrograph (SEM). The results of this wear test show that the wear factors of the both composite ceramics are similarly low and their mechanical properties are much better than those of the alumina monolith and the zirconia monolith. According to these results, it is predicted that joint prostheses of the composite ceramics are safer against break down and have longer lifetime compared with alumina/alumina joint prostheses. [ABSTRACT FROM AUTHOR]

A new artificial joint model based on the system of bio-cartilage and porous β-tricalcium phosphate (TCP) was fabricated. The porous β-TCP with 100 μm or so of average pore diameter was prepared by hydrothermal treatment and successive ceramic foaming method. The bio-cartilage part consisted of 0.15% collagen gel with chondrogenic ATDC5 cells. ATDC5 cells in the bio-cartilage/porous β-TCP system were cultured to give an artificial joint model. In the artificial joint model, metachromasia was observed with toluidine blue staining. From the FT-IR spectra of the bio-cartilage, formation of proteoglycans was suggested. In addition, alkaline phosphatase activity increased dramatically. ATDC5 cells grew to produce cartilage matrices in this system. [Copyright &y& Elsevier]

Ultra-high molecular weight polyethylene (UHMWPE) has been used as a bearing surface for artificial joints and its wear is one of the limiting factors for long term use of such prosthetic implants. Previous studies have revealed that the oriented and crystallized UHMWPE, prepared by plane compression, enhanced the resistance of wear. In this paper, we studied the influence of compression by half-spherical shape on the preferred orientation and wear. UHMWPE with slight cross-linking was compressed at molten state by using a sphere. A half-spherical cavity was molded, and the molded shape was similar to a cup. Wide angle X-ray diffraction (WAXD) tests revealed that the (1 1 0) and the (2 0 0) crystalline planes were orientated along the half-spherical cavity surface (3D orientation). The melting point, the heat of fusion, and the density near the curved surface showed relatively higher than a conventional UHMWPE. These structure and physical properties can fit to the results of plane orientation. Wear tests were performed using hip simulator, and the weight loss was compared to that of a conventional cup. In conclusion, the compression with the 3D orientation enhances wear resistance, similarly to the plane orientation results, and is useful for molding an improved cup. [Copyright &y& Elsevier]

While alumina is the only material applied to all-ceramic joint prostheses, zirconia has high potential too, because it has high strength and fracture toughness. However, wear of zirconia/zirconia combination is too high for clinical use. It is likely that a combination of different materials may improve wear properties. In this study, wear tests were carried out with an end-face wear testing apparatus for four material combinations: zirconia/zirconia (Z/Z), zirconia/alumina (Z/A), alumina/zirconia (A/Z), and alumina/alumina (A/A). Mean contact pressures were 5 and 10 MPa, and sliding velocity was 40 mm/s. Wear tests continued for 72 h and total sliding distance was 10 km. After the test, the wear factor defined by (wear volume)/(applied load×sliding distance) was calculated. Worn surfaces were observed with a scanning electron microscope and analyzed by means of Raman spectroscopy. When zirconia was combined with zirconia counterface, the wear factor of zirconia under 5 MPa was about 2.5×10−7 mm3/N m and that under 10 MPa was about 1.9×10−5 mm3/N m. In the case of Z/Z combination, the wear factor was very high due to adhesive wear and the phase transformation. When zirconia was combined with alumina counterface, the wear factor of zirconia under 5 MPa was about 1.7×10−9 mm3/N m and that under 10 MPa was about 1.7×10−7 mm3/N m. In the case of Z/A and A/Z combinations, the wear factor of zirconia decreased drastically as compared with Z/Z combination, because adhesive wear was controlled. Micro cracking and third body abrasion were predominant in this case. [Copyright &y& Elsevier]

Seven men mean age 37 years (range 24-45) who had destroyed metacarpophalangeal joints as a result of pyogenic infection underwent reconstruction of the joint with osseointegrated silicone implants. The interval from infection to reconstruction varied from 5 months to 13 years. At mean follow-up 10 (8-12) years postoperatively the titanium fixtures were all well osseointegrated. The silicone spacer had fractured in one case. The extension lag was 16 (10-20)° and the range of movement (ROM) 34 (30-40)°. Our data confirm previous observations about the successful long-term osseointegration of titanium fixtures used for the attachment of joint prostheses in the hands of patients with rheumatoid arthritis or osteoarthritis. We conclude that titanium fixtures can be used successfully to fix joint mechanisms for reconstruction of small joints after pyogenous arthritis of the hand and can be used for fixation of joint mechanisms in such cases. [ABSTRACT FROM AUTHOR]

Osseointegrated proximal interphalangeal joint prostheses with a replacable joint spacer were used in 25 joints in 19 patients (five men and 14 women) aged 45 (16-67) years. Indications for surgery were post-traumatic arthrosis (nine joints in eight patients), primary osteoarthrosis (10 joints in eight patients), and rheumatoid arthritis (six joints in three patients). A silicone joint spacer was attached to titanium fixtures by short titanium stems that extended from the spacer and fitted into a central canal in the screws. The arthroplasty was done in one stage, which included resection of the joint followed by grafting of marrow and cancellous bone from the iliac crest into adjacent medullary cavities before insertion of the titanium fixture. Follow up at 8.5 (5-11) years showed that 47 out of 50 fixtures (94%) had successfully osseointegrated while 17 of 25 joint spacers (68%) had fractured. However, because of the design of the prostheses fractured joint spacers could easily be replaced and a new spacer could be connected to already osseointegrated screws. The joint spacer was replaced in 11 fingers once or several times. Range of movement (ROM) in the whole series (four fusions excluded) was 41 (0-85)° with an extension defect of 15 (0-55)°. In eight joints with permanently intact joint spacers the ROM was 39 (0-60)° with extension defects of 16 (0-40)°. In six joints in which the spacer was replaced once the ROM was 43 (0-85)° with an extension defect of 16 (0-55)°. Our data confirm good long-term osseointegration of titanium fixtures and that a joint spacer, if needed, can be replaced by a new spacer that can be attached to already osseointegrated screws without jeopardising the ROM. [ABSTRACT FROM AUTHOR]

[Display omitted] • A temperature-sensitive antifriction and antiwear behavior was observed. • The effects of sliding conditions on the wear of Ti6Al4V/UHMWPE contact were studied. • The influence of the microgels in synovial fluid on the tribological behavior was analyzed. • The novel wear mechanisms and smart lubrication roles for the contact were illustrated. In the pressent work, nanosized poly (N-isopropyl acrylamide) (PNIPAM) microgels were prepared and used as lubricant additives in bovine calf serum (BCS) for titanium alloy/ultra-high molecular weight polyethylene contact. The effects of sliding speed, load, and temperature on the lubrication behavior were studied on a pin-on-disc tribometer. The tribological results showed that the PNIPAM microgels can significantly improve the lubricity of BCS solution. The PNIPAM microgels exhibited notable temperature-sensitive lubrication characteristics. When the temperature was close to the low critical solution temperature of the PNIPAM microgels, the contact had the lowest friction coefficient due to the formation of a good lubricating layer with collapsed microgels and proteins. This discovery contributes to establishing a new strategy for friction-reduction and antiwear of titanium alloy artificial joint materials. [ABSTRACT FROM AUTHOR]

Hip joint replacements using highly cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) as a bearing material offer an effective treatment to arthritis. However, the bearing wear may affect the longevity of implants which requires more rigorous investigations. UHMWPE wear is highly dependent on cross-shear (CS) as a result of the multidirectional motion of bearings. Previously, a wear model has been developed with the potential to provide accurate simulation, of which the wear was determined as an exponential function of sliding distance with CS at the crossing angle of 90°, and the effect of CS for an arbitrary angle was quantified to be proportional to the perpendicular component of sliding distance. In the present study, the wear was proposed as the exponential function of frictional work. In particular, contact pressure was incorporated into the calculation of frictional work by considering that the friction coefficient is a function of contact pressure. In addition, the CS quantification for arbitrary crossing angles was considered by coupling the sliding distance and frictional force. The computational formulations of the present and previous models were compared by applying the models to a 36 mm diameter metal-on-polyethylene total hip prosthesis with highly cross-linked UHMWPE at 5 Mrad irradiation under simulated walking conditions. The simulation was also validated against the published results of hip simulator tests with respect to the influence of motion/loading condition on wear. The study showed markedly improved computational predictions with wear rate discrepancies in the range of 8–25% for two kinematic conditions either with the fixed or with varying direction of load. The results show the important role of both the frictional work and contact pressure, and they should be both incorporated appropriately to enhance the computational modelling. • Wear of highly cross-linked UHMWPE has been modelled to improve understanding of wear mechanism for hip joint prostheses. • A new model has been theoretically introduced and validated against hip joint simulator tests, based on a previous method. • The wear model has been improved for quantifying the cross-shear wear incorporating frictional work and contact pressure. • Both frictional work and contact pressure should be formulated appropriately to enhance computational modelling. [ABSTRACT FROM AUTHOR]

The commissioning of a new form of 10-station hip joint simulator is described and the results of a study of the performance of zirconia-ultra-high molecular weight polyethylene (UHMWPE) total replacement hip joints in the familiar Charnley head size of 7/8 inch (22.225 mm) diameter are presented. The head size is referred to as 22 mm for brevity and consistency throughout the paper. The simulator provided very consistent and repeatable results and the new machine, together with the methods of investigation adopted, offer an excellent facility for the further evaluation of existing and new prostheses. The findings are compared with the outcome of previous laboratory simulator and clinical studies of ceramic-polyethylene implants of similar diameter. It was found that a relatively rapid penetration of the head into the cup was followed by a very low, steady, long-term penetration rate after about two million loading cycles. The mean long-term volumetric penetration rate was 6.28 mm3/10(6) loading cycles. When the linear penetration rates were assessed by direct measurement on a coordinate measuring machine, or deduced from the tunnelling expression, the resulting values were very similar and small at 0.019 and 0.016 mm/10(6) loading cycles respectively. It is generally assumed that one million loading cycles is equivalent to about one year of service in the body and if this equivalence is accepted, these penetration rates compare very favourably with a clinical evaluation of alumina heads of the same diameter, which yielded a mean long-term penetration rate of 0.022 mm/year. [ABSTRACT FROM AUTHOR]

Artificial joint surface coating is a hot issue in the interdisciplinary fields of manufacturing, materials and biomedicine. Due to the complex surface characteristics of artificial joints, there are some problems with efficiency and precision in automatic cladding path planning for coating fabrication. In this study, a path planning method for a laser cladding robot for artificial joints surface was proposed. The key of this method was the topological reconstruction of the artificial joint surface. On the basis of the topological relation, a set of parallel planes were used to intersect the CAD model to generate a set of continuous, directed and equidistant surface transversals on the artificial joint surface. The arch height error method was used to extract robot interpolation points from surface transversal lines according to machining accuracy requirements. The coordinates and normal vectors of interpolation points were used to calculate the position and pose of the robot tool center point (TCP). To ensure that the laser beam was always perpendicular to the artificial joint surface, a novel laser cladding set-up with a robot was designed, of which the joint part clamped by a six-axis robot moved while the laser head was fixed on the workbench. The proposed methodology was validated with the planned path on the surface of an artificial acetabular cup using simulation and experimentation via an industrial NACHI robot. The results indicated that the path planning method based on topological reconstruction was feasible and more efficient than the traditional robot teaching method. [ABSTRACT FROM AUTHOR]

In the research of artificial joint biomechanics, it is a common method in the world to evaluate the biomechanical properties of the implanted fixtures through experiments in vitro . The domestic research started late, and the corresponding testing software were lacking. There is still no special software. In this paper, an integrated software test system was designed and built based on the existing hardware system, including:hardware control, data collection, data save, data processing and display. It can directly show the 3D motion trajectory and the angle curve of joints. The system can accurately measure the relative motion angle value, external torque value, and inter pressure value of each joint. It has some reference significance for the development of the artificial joints' evaluation system.

In the research of artificial joint biomechanics, it is a common method in the world to evaluate the biomechanical properties of the implanted fixtures through experiments in vitro . The domestic research started late, and the corresponding testing methods were lacking. There is still no unified standard. In this paper, a complete hardware test system was designed and built around the existing mechanical testing machine, including:binocular vision catcher, torque bearing clamp, film pressure sensor and so on. The system can accurately measure the relative motion angle value, external torque value, and inter pressure value of each joint. It has some reference significance for the forming and standardization of the artificial joints' evaluation system.