(28 days)
The patient should be skeletally mature to receive a knee replacement. Patients should have adequate bone stock and size to support and accept the prosthesis.
The patient's need for knee replacement should be due to one or more of the following conditions:
- · Non-inflammatory degenerative joint disease including osteoarthritis, traumatic arthritis, or avascular necrosis.
- · Inflammatory degenerative joint disease including rheumatoid arthritis.
- · Functional deformity such as varus, valgus or flexion deformities.
- · Revision procedures where other treatments or devices have failed.
- · Fractures that are unmanageable using other techniques.
Signature Orthopaedic's World Knee replacement components may be intended for cemented or cementless use. Please verify whether the particular component is intented for cementless use by checking the package label.
The World Knee Total Knee System is a modular knee system consisting of a femoral component, meniscal insert, a patella and a tibial baseplate or all polyethylene tibia. The femoral component and meniscal inserts are available as posterior Stabilized or cruciate retaining variants. Cruciate retaining meniscal inserts are available as standard or ultracongruent designs. The tibial baseplate components covered in this 510(k) is made of Titanium as part of the cemented version. The patella components are available in a spherical or non-symmetrical designs.
The primary purpose of this Special 510(k) Device Modification to the World Knee System is to notify the FDA of the change in materials used to manufacture the tibial inserts (all variants (CR, PS and UC) of modular meniscal insert and all-poly tibial baseplate components) to Vitamin-E Stabilized, 100 kGy crosslinked UHMWPE (Vit-E HXLPE). This 510(k) also notifies the FDA of minor design updates to the implants and reusable instruments.
Materials: Wrought Cobalt-28Chromium-6Molybdenum Alloy (ASTM F1537-11) for the femoral component, Wrought Titanium-6Aluminium-4Vanadium ELI Alloy (Ti6Al4V ELI, ASTM F136-13) for the tibial baseplate components, Ultra-High-Molecular-Weight Polyethylene (UHMWPE) for all variants of the patellar implants, Ultra-High-Molecular-Weight Polyethylene (UHMWPE) or Vit-E HXLPE for the Allpoly tibial baseplate components and modular meniscal tibial inserts.
This document is a 510(k) premarket notification from the FDA, approving the "World Knee Total Knee System". It primarily discusses the substantial equivalence of a modified device (incorporating Vitamin-E Stabilized, crosslinked UHMWPE for tibial inserts) to its previously cleared predicate devices.
Crucially, this document focuses on mechanical and material engineering evaluations, not on clinical performance studies involving human subjects or AI algorithms. Therefore, it does not contain information related to the acceptance criteria and study designs that would be relevant for devices that perform functions like image analysis or diagnostic assistance (e.g., AI-powered medical devices).
The acceptance criteria mentioned in this document are entirely related to the physical and material properties of the knee implant. The "study" proving the device meets these criteria is a series of engineering evaluations and material testing, performed in a lab setting, not a clinical trial with human subjects.
Therefore, many of the requested categories for AI/clinical study information (e.g., sample size for test set, data provenance, number of experts for ground truth, MRMC study, effect size, training set details) are not applicable to this type of device submission.
Here's an attempt to fill in the table and address the questions based solely on the provided text, recognizing that most of the requested information (especially for AI/clinical studies) is absent:
Acceptance Criteria and Device Performance (Based on Engineering Evaluations)
| Acceptance Criteria (Performance Metric) | Reported Device Performance (Test Results) | Notes & Context from Document |
|---|---|---|
| Material Properties of Vit-E HXLPE vs. standard UHMWPE: | Conducted to verify substantial equivalence and/or superiority. | |
| Density (ASTM F648 and D792) | Not explicitly stated; implied "equal to and/or better than predicate device" | Engineering evaluation performed. |
| Mechanical Properties (ASTM F648, F2759, D695, F2183) | Not explicitly stated; implied "equal to and/or better than predicate device" | Engineering evaluation performed. |
| Melting Point, Crystallinity, Enthalpy of Fusion (ASTM F26351) | Not explicitly stated; implied "equal to and/or better than predicate device" | Engineering evaluation performed. |
| Swell Ratio and Crosslink Density (ASTM F2214) | Not explicitly stated; implied "equal to and/or better than predicate device" | Engineering evaluation performed. |
| Fatigue Crack Propagation and Coefficient (ASTM E647) | Not explicitly stated; implied "equal to and/or better than predicate device" | Engineering evaluation performed. |
| Oxidation Challenge (ASTM F2003, F2102 for 2 & 6-week accelerated aging) | Not explicitly stated; implied "equal to and/or better than predicate device" | Engineering evaluation performed. |
| ESR Testing for residual free radical content and Transvinylene Index (TVI) (ASTM F2381) | Not explicitly stated; implied "equal to and/or better than predicate device" | Engineering evaluation performed. |
| Resistance to wear (5 million cycles as per ISO 14243 Part 1 and 2) | Not explicitly stated; implied "equal to and/or better than predicate device" | This is a specific performance criterion for wear resistance. |
| Mechanical Integrity of Vit-E HXLPE tibial insert components & baseplate locking mechanism vs. standard UHMWPE tibial insert | Not explicitly stated; implied "substantial equivalence" | Verification conducted. |
| Risk Analysis and Design Control Review | "found no new or changed risks relative to the Indications for Use and Efficacy of the Subject Device." | A critical acceptance point for safety and efficacy. |
Study Details and Ground Truth Establishment
-
Sample size used for the test set and the data provenance:
- Test Set Sample Size: Not applicable in the context of human clinical data or images. The "test set" here refers to material samples or components tested in a lab for physical and mechanical properties. The specific number of samples tested for each engineering evaluation (e.g., number of fatigue specimens, wear resistance samples) is not provided in this summary.
- Data Provenance: Not applicable in the context of geographical origin or retrospective/prospective clinical data collection. The data comes from laboratory testing and engineering evaluations performed by the manufacturer (Signature Orthopaedics Pty Ltd, Australia and Ireland).
-
Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Not applicable. Ground truth for material and mechanical properties is established through adherence to international and industry standards (e.g., ASTM, ISO) and the results of validated engineering tests. This is not a diagnostic device where human experts establish ground truth.
-
Adjudication method (e.g. 2+1, 3+1, none) for the test set:
- Not applicable. This is not a study requiring adjudication of expert opinions. The "results" are quantitative measurements from standardized laboratory tests.
-
If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:
- No. An MRMC study is completely irrelevant for this device. This is a knee implant, not a diagnostic imaging device or an AI application.
-
If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- No. This is not an algorithm or AI device. "Performance" here refers to the device's physical and material integrity, not its diagnostic accuracy.
-
The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- The "ground truth" for this device's performance is established by validated engineering and material testing standards (e.g., ASTM, ISO standards). These standards define the methodologies and acceptable ranges for properties like density, mechanical strength, wear resistance, and oxidation. The goal is to demonstrate that the new material/design is "substantially equivalent" or superior to existing, legally marketed predicates in terms of these physical characteristics.
-
The sample size for the training set:
- Not applicable. This is not a machine learning or AI device that requires a training set.
-
How the ground truth for the training set was established:
- Not applicable.
In summary, this FDA 510(k) approval document is focused on demonstrating the physical and mechanical equivalence of a new knee implant material and minor design updates to a previously cleared device, based on established engineering and material science principles, not on clinical performance or AI/diagnostic evaluation.
§ 888.3560 Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis.
(a)
Identification. A knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace a knee joint. The device limits translation and rotation in one or more planes via the geometry of its articulating surfaces. It has no linkage across-the-joint. This generic type of device includes prostheses that have a femoral component made of alloys, such as cobalt-chromium-molybdenum, and a tibial component or components and a retropatellar resurfacing component made of ultra-high molecular weight polyethylene. This generic type of device is limited to those prostheses intended for use with bone cement (§ 888.3027).(b)
Classification. Class II.