(441 days)
Candidates for total or unicompartmental knee replacement include patients with a severely painful and/or severely disabled joint resulting from osteoarthritis, post-traumatic arthritis, or a failed previous implant. In candidates for unicompartmental knee arthroplasty, only one side of the medial or lateral compartment) is affected.
The Sigma® C/R Porocoat® Femoral Components are intended for cementless use as the femoral component of a Total Knee Replacement system.
In the US, all other porous coated components have been cleared for CEMENTED USE ONL Y. Any Non-Porous coated components are intended for CEMENTED USE ONLY.
A total knee prosthesis is composed of individually packaged femoral, tibial and patellar components designed to replace the natural articular surface of the knee joint. The femoral component is a metal implant, with or without a porous coating. The tibial component may be an all polyethylene component or comprised of a metal tibial tray with or without porous coating, and a polyethylene insert and locking components. Some metal components have modular stems, sleeves and/or modular wedges. The patella component may be of an all polyethylene design or may be a metal backed polyethylene component.
This 510(k) submission is to provide MRI compatibility labeling for the PFC SIGMA Knee System. No clinical studies were conducted as the submission is based on non-clinical testing for MRI compatibility.
Here's a breakdown based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
| Test Type | Acceptance Criteria | Reported Device Performance |
|---|---|---|
| Magnetically Induced Displacement Force (ASTM F2052-14) | No excessive movement or dislodgement of the device in the MR environment. (Implied by safety concerns addressed in the FDA guidance and ASTM standards) | Testing concluded no safety issues related to magnetic field interactions under specific conditions. |
| Torque (ASTM F2213-06) | No excessive rotation or twisting of the device in the MR environment. (Implied by safety concerns addressed in the FDA guidance and ASTM standards) | Testing concluded no safety issues related to magnetic field interactions under specific conditions. |
| Radiofrequency (RF) Heating (ASTM F2182-11a) | No unsafe temperature increase in the device due to RF energy from the MR scanner that could impact patient safety. (Implied by safety concerns addressed in the FDA guidance and ASTM standards) | Testing concluded no safety issues related to magnetic field interactions under specific conditions. |
| Image Artifacts (ASTM F2219-07) | Image quality should not be unacceptably degraded by device-induced artifacts, or the effects assessed and characterized. (Implied by concerns about imaging) | Effects of the implants on image quality were evaluated. |
| MR Conditional Labeling (ASTM F2503-13) | The device should meet criteria to be labeled as "MR Conditional," meaning it can be safely used in a specified MR environment under defined conditions. | Testing supports an MR conditional label as described in FDA Guidance Document and ASTM F2503-13. |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set: The document states that "worst-case components and constructs" were evaluated for RF Heating and image artifacts. However, a specific numerical sample size for the devices tested is not provided.
- Data Provenance: The data is non-clinical, originating from laboratory testing (often referred to as ex-vivo or in-vitro when applicable to medical devices). The country of origin for the testing itself is not explicitly stated, but it follows US FDA guidance and ASTM standards. The study is retrospective in the sense that the device design already existed and was being evaluated for an additional claim.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
This section is not applicable. The ground truth for MRI compatibility is established through standardized physical tests and measurements, not through expert consensus on interpretations of images or clinical outcomes. The "ground truth" is whether the device physically behaves safely and predictably in an MR environment according to predefined engineering standards.
4. Adjudication Method for the Test Set
This section is not applicable. As the evaluation involved physical measurements and adherence to engineering standards, there was no need for expert adjudication in the traditional sense of clinical trial data interpretation.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
A Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. The submission is for MRI compatibility labeling based on non-clinical testing.
6. Standalone (i.e., algorithm only without human-in-the-loop performance) Study
A standalone performance study of an algorithm was not done. This submission pertains to the physical properties of a knee implant system and its interaction with MRI, not an algorithm.
7. Type of Ground Truth Used
The ground truth used was based on results from standardized non-clinical physical and engineering tests (magnetically induced displacement force, torque, RF heating, image artifacts) as defined by FDA guidance and ASTM standards (e.g., ASTM F2052-14, ASTM F2213-06, ASTM F2182-11a, ASTM F2219-07, ASTM F2503-13).
8. Sample Size for the Training Set
This section is not applicable. There was no "training set" as this was not a machine learning or AI-based study.
9. How the Ground Truth for the Training Set Was Established
This section is not applicable.
§ 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.