We help our clients gain regulatory approval for hip replacement medical devices
We offer a broad range of static, dynamic, computational, and wear testing services for hip replacement devices. All of our test procedures follow international test standards as described below.
Our engineering team is active in ASTM and ISO arthroplasty standards committees to ensure the latest industry best-practices are applied to your test. If a non-standard test is needed, our engineering team will develop and incorporate modifications to suit your specific device and data needs.
Having a strong foundation in clinical research provides you with the additional value of a clinically-relevant test procedure. We pride ourselves on the ability to meet a customer’s specific needs with a wholly unique, tailored solution.
Guide for Evaluation of Modular Hip and Knee Implants
Guide suggesting areas of modular hip and knee implants for evaluation. This guide is not all inclusive, but guides common topics of modular implants such as: assembly, disassembly, and fatigue properties to assess various designs.
Disassembly Forces of Hip Liner Locking Mechanism
This test method determines the force required to disengage the hip liner from the acetabular shell. Test methods include: axial disassembly (push-out), pull out or lever out, and torque out disassembly. The axial disassembly test measures the locking strength of the liner. The pull out or lever out test simulates the resistance of the liner to disengage due to impingement. The final test method simulates the resistance of the locking mechanism to a high friction event that attempts to rotate the liner within the shell. Five samples are tested for each test method.
Hip Fretting Corrosion Test
Fretting corrosion test for the femoral head-neck taper connection. Method 1: determines damage through assessing corrosion products and particulate debris after 10 million cycles of axial load applied to the femoral head in a saline fluid environment to simulate mechanically assisted crevice corrosion. Method II: is a shorter-term electrochemical evaluation of fretting corrosion examining change in voltage potential between anodic and cathodic components of the THR.
Axial Disassembly Force of Taper Connections
This test method measures the axial fastening strength of Morse taper connections of THR implants. An axial tensile force is applied until the taper connection disengages. The maximum force applied is recorded.
Specification for Metal Femoral Components
Specification for fatigue testing and determining coating integrity of femoral THR stems. Fatigue testing can be performed according to ISO 7206-4 and ISO 7206-6. Samples are tested for 10 million cycles. Coating integrity can be assessed according to ASTM F1044 (shear strength), ASTM F1147 (tensile strength) and ASTM F1978 (abrasion resistance).
Fatigue Testing of Proximally-Fixed, Modular Femoral Stems
Test method for fatigue testing of femoral stems intended for proximal fixation with modular inter-body connections in the metaphyseal region. Samples are tested for 10 million cycles in a similar manner to ISO 7206-4.
Hip Impingement Testing
Test method for hip impingement testing. Under dynamic impingement conditions, acetabular component fatigue, acetabular liner deformation and wear, as well as femoral head dislocation are evaluated. Samples are tested in 0.2 million cycle intervals until failure, or to a maximum of 1.0 million cycles. The reference position of each sample may need adjustment at each interval to ensure impingement contact is consistent. There are two methods for performing this test. Method I (2014): Three samples are tested under impingement, and three samples are tested without impingement and used as reference samples. The reference samples provide wear results without impingement. Wear measurements are performed at each interval. Method II (in development): Three samples are tested under impingement with no reference samples. Acetabular liners are assessed at each interval for acceptable and unacceptable damaged modes as well as evidence of liner separation or loosening.
Guide for Characterization of Wear from Metal-on-Metal Implants
Standard guide for measuring volumetric wear and measurements of wear depth through use of coordinate measuring machine (CMM) on the femoral head and acetabular shell. A high-density point cloud is obtained of each worn articular insert and compared against an identical non-worn articular surface to calculate maximum wear depth and total volumetric wear. An iterative removal of the surface’s worn areas is employed to approximate the geometry of the non-worn articular insert.
FEA for THR Femoral Stems
Describes a standardized method for finite element analysis (FEA) model to estimate stresses and strains on a femoral hip stem. This test method is used to identify worst-case size combinations for a particular implant family as well as the influence of device design, materials, and manufacturing variables.
Fatigue Testing of Acetabular Components
Test method for evaluating fatigue of acetabular THR cups. A cyclic load is applied to an acetabular cup fixed at a 55 deg angle to the load direction until run-out or failure of the cup. An arc beneath the loaded area of the cup is unsupported to simulate clinical bone loss conditions. Testing is performed either in air at ambient temperature or in fluid at body temperature. This test method is applicable to mono-block and modular acetabular components.
Standard Guide for Characterization of Material Loss from Conical Taper Junctions in Total Joint Prostheses
This guide specifies a method to measure the surface and estimate the in-vivo material loss from taper junctions such as the femoral head / stem junction or adapter sleeve from explanted modular hip prostheses. This guide utilizes a coordinate measuring machine (CMM) to estimate the depth of material loss and volume of material loss from the taper surface.
High Demand Hip Wear Test of Hard-on-Hard Articulations
This guide suggests possible high demand test features to be considered in evaluating hard-on-hard articulations. A standard hip wear test according to ISO 14242 is performed prior to high demand testing. Possible high demand tests include: higher acetabular liner/shell angle, the addition of 3rd body particles, higher loading parameters, stop-dwell-start programmed into waveform, and micro-separation of articulating surfaces.
Surface Finish Requirements for Articulating Surfaces of Hip Implants
This standard specifies requirements for articulating surfaces in THR. Articular surface sphericity and surface finish are assessed using CMM and surface profilometer systems.
Fatigue Testing of Femoral Stems
Test method for fatigue testing of the distal portion of a femoral stem under axial loading of simulated gait cycles. A total of six samples must survive to run-out of 5 million cycles. This standard is similar to ASTM F2068.
Fatigue Testing of Neck Region of Femoral Stems
Test method for fatigue testing of the neck region of a femoral stem under axial loading of simulating gait cycles. a total of six samples must survive to run-out of 10 million cycles with a peak load of 5340 N.
Static Load Test of Femoral Head
A femoral head is assembled onto the femoral stem taper using the specified assembly force. Load is applied to the femoral head in line with the femoral stem taper until the femoral head fractures (burst) or the maximum specified load is reached.
Deformation of Acetabular Shells
Test method for evaluating the magnitude of deflection of an acetabular cup when loaded across the open face. A test frame can be used to apply a constant load to opposite edges of the cup while a coordinate measuring machine simultaneously measures the cup deflection compared to the unloaded state. The degree of cup deflection may affect the tribological properties of the THR system, particularly for hard-on-hard bearings.
Torsion Test of Femoral Head
A femoral head is assembled onto the femoral stem taper using the specified assembly force. Torsion is applied to the femoral head while holding the stem rigid until movement of the head occurs. The peak torsion is recorded as the loosening torque.
Hip Wear Test
Wear performance of hip replacements is assessed via loading and displacement parameters as specified in ISO 14242-1. Up to 6 systems can be assessed on OIC’s AMTI Hip Simulator. Samples complete 5 million cycles of testing and wear is measured through gravimetric analysis following ISO 14242-2. Typical add-ons for this test are accelerated aging of polyethylene components (ASTM 2003), wear particle characterization (ASTM F1877), surface roughness characterization, and CMM measurement to evaluate dimensional changes resulting from the test. Adverse condition testing is also commonly performed to evaluate TKR device performance under non-ideal conditions such as increased load, high range of motion, and roughened or pre-damaged articular surfaces.
Hip Range of Motion
This standard is a guide for testing of THR components. As part of a larger standard, a minimum range of motion of the implants is provided along with a method for measuring maximum range of motion using the physical components.