We help our clients gain regulatory approval for total and partial knee replacement medical devices
We offer a broad range of static, dynamic, computational, and wear testing services for total and partial knee 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.
Total Knee Replacement Constraint
Test method for measuring constraint on TKR under specific loading conditions. These include constraint determination in: antero-posterior draw, medio-lateral shear, rotary laxity, valgus-varus rotation, and distraction. Samples are loaded in the specified directions and displacement is measured.
Patellar Prosthesis Specifications
Specifies basic descriptions and device geometries of patellar resurfacing devices. The standard lists relevant failure modes, which should be considered in determining safety and efficacy of the device. These include, but are not limited to: shear testing, stress analysis, and contact area and pressure distributions. Additionally, durability of the patellofemoral device according to ISO 14243-5 can be performed.
Tibial Tray Fatigue Test
Similar to ISO 14879, this standard describes cyclic fatigue testing of tibial trays for 10 million cycles, or until failure. The tibial tray is mounted at the center line, with the medial side left unsupported, and the load applied on the unsupported region.
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.
Specification for Metal Femoral Components
Specifies basic descriptions and device geometries of total knee replacements. Various tests are listed in this specification to assess performance including contact area and contact pressure testing. This test examines the area and magnitude of stresses applied between the femoral component and tibial insert of a total knee replacement at various flexion angles through mapping on pressure films. In conjunction with this test, clients consider testing according to: ASTM F1800, ASTM F2777, ASTM F732, ISO 14243, ASTM F748, ASTM F1044, ASTM F1147, ASTM F1160 and ASTM F1223.
Tibial Baseplate/Insert Resistance to Dynamic Disassociation
Test method for evaluating the potential of mobile TKR bearing disassociation under repeated forces at high flexion. Five samples are tested for a total of 220,000 cycles, equivalent to 30 extreme motions per day for 20 years, or until failure of the retention mechanism.
Test Method for Evaluating Mobile Bearing Knee Dislocation
Test method to determine the dislocation resistance (constraint) of mobile-bearing TKR designs with regards to femoral component disassociation and behavior of the knee insert. Testing is performed at 4 different flexion angles and the mode of failure (either spin-out or spit-out) is reported for each angle.
Tibial Insert Endurance and Performance Under High Flexion
Test method describing fatigue testing of tibial inserts at high-flexion angles of the femoral component. Five TKR samples are tested for 220,000 cycles or until failure. Pre- and post-test analysis of material deformation and damage are performed using a Coordinate Measuring Machine (CMM). Inserts shall be artificially aged according to ASTM F2003.
Fatigue Testing of Unicondylar Tibial Tray Components
Test method describing fatigue testing of unicondylar tibial tray components supported at only anterior and posterior edges by thin rollers. Cyclic loading is applied to the midline of the tibial tray using a spherical indenter and polymer spacer for 10 million cycles or until device failure.
Total Knee Replacement Loading Profiles
Provides a guide for waveforms and loading profiles that approximate activities of daily living to be applied in a TKR joint simulator. Profiles are described for: straight walking gait, stair ascent, stair descent, sit to stand to sit, pivot turn, and crossover turn. These profiles can be used in OIC’s AMTI Knee Simulator.
FEA for TKR Femoral Components
Test method providing the standardization of the finite element analysis (FEA) model for estimating stresses and strains on femoral components. 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 TKR Femoral Components Under Closing Conditions
Fatigue testing applied to the medial condyle of a femoral TKR component in an inverted position to simulate single condyle loading at 90° knee flexion. The femoral component is potted to a defined depth which leaves the regions of highest stress exposed to the test. Cyclic loading is applied until run-out is achieved or device failure. This standard is still in development.
Endurance Properties of Tibial Trays
Similar to ASTM 1800, this standard describes cyclic fatigue testing of tibial trays for 10 million cycles, or until failure. The tibial tray is mounted at the center line, with the medial side left unsupported, and the load applied on the unsupported region.
ISO 14243-1 Load-Control Knee Wear Test and ISO 14243-3 Displacement-Control Knee Wear Test
Joint simulator wear testing evaluates the wear performance of TKR prosthesis design and bearing materials under physiological conditions for device optimization and to meet regulatory requirements. Up to 6 TKR implants can be assessed on OIC’s AMTI Knee Simulator. Samples complete 5 million cycles of testing under force-controlled (ISO 14243-1) or displacement-controlled (ISO 14243-3) kinematics. Wear is measured through gravimetric analysis following ISO 14243-2. Typical additions for this test are accelerated aging of polyethylene components (ASTM F2003), 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.
ISO 14243-5 Durability Performance of the Patellofemoral Joint
Durability of the patellar and femoral components are tested through joint wear simulation that follows a squatting sub-cycle and two low flexion sub-cycles. Loading and displacement waveforms are applied for 50,000 cycles or until patellofemoral joint failure occurs in the form of delamination, cracking or other mechanical failure. It is recommended to test the largest femur with the smallest patella to achieve the highest contact stress and subsurface shear for worst-case conditions.
Specification for Surface Finish of Knee Replacements
Defines the measurement procedure for assessing surface roughness at multiple locations on a knee replacement component. This standard applies to partial and total knee replacements made of metallic, ceramic, and polymeric materials.