(74 days)
The Sigma Co-Cr Tibial Trays are intended for use in total knee replacement surgery for patients suffering from severe pain and disability due to permanent structural damage resulting from rheumatoid arthritis, osteoarthritis, post-traumatic arthritis, collagen disorders, pseudogout, trauma or failed prior surgical intervention. The Sigma Co-Cr Tibial Trays are intended for cemented use only.
This document describes a medical device, the DePuy Sigma Co-Cr Tibial Trays, and its regulatory submission. It is a 510(k) premarket notification, which means the manufacturer is claiming that their new device is "substantially equivalent" to an existing, legally marketed device (the predicate device). This type of submission generally does not involve a clinical study to prove new acceptance criteria based on performance because the device is not claiming novel performance, but rather equivalence in safety and effectiveness to a predicate.
Therefore, the requested information about acceptance criteria, study details, sample sizes, expert involvement, adjudication, MRMC studies, standalone performance, and ground truth for a device performance study is not applicable to this 510(k) submission.
Instead, the "acceptance criteria" and "study" in this context refer to the criteria for demonstrating substantial equivalence to the predicate device, which is a regulatory assessment rather than a performance study.
Here's how to address the questions given the nature of a 510(k) for substantial equivalence:
1. A table of acceptance criteria and the reported device performance
Since this is a substantial equivalence submission, the "acceptance criteria" are the demonstration of equivalence to the predicate, and the "performance" is a comparison to the predicate's known characteristics.
| Acceptance Criteria (for Substantial Equivalence) | Reported Device Performance (Comparison to Predicate) |
|---|---|
| Same Intended Use as the predicate device. | The Sigma Co-Cr Tibial Trays have the "same intended use" as the tibial trays of the Darwin Knee System (K943462). Both are for total knee replacement surgery for patients suffering from severe pain and disability due to permanent structural damage from conditions like rheumatoid arthritis, osteoarthritis, etc., and are intended for cemented use only. |
| Similar Design to the predicate device. | The Sigma Co-Cr Tibial Trays are "similar in design" to the Darwin tibial trays cleared in K943462. They can be used with the existing PFC Sigma femoral and patella components (which were previously cleared with the Darwin system). |
| Similar Materials to the predicate device, or changes do not raise new questions of safety or effectiveness. | The tibial tray material has been changed from forged Ti-6Al-4V alloy (predicate) to forged Co-Cr-Mo alloy (new device). The documentation implies this change does not raise new questions of safety or effectiveness, as it states "Based on similarities in design, material, manufacturing method and intended use, DePuy believes that the Sigma Co-Cr Tibial Trays are substantially equivalent." (Further material testing, e.g., biocompatibility, mechanical properties, would have been submitted to demonstrate this, but explicit results are not detailed in this summary.) |
| Similar Manufacturing Method to the predicate device. | The documentation explicitly states "similarities in... manufacturing method." |
| No New Questions of Safety or Effectiveness are raised by the differences. | The FDA's substantial equivalence determination implies they agree that no new questions of safety or effectiveness were raised. |
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
Not applicable. This is a claim of substantial equivalence based on design, materials, manufacturing, and intended use comparison, not a clinical performance study with test sets or data provenance.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
Not applicable. There was no "ground truth" to establish for a test set in the context of a clinical performance study. The "ground truth" here is the regulatory determination of substantial equivalence by the FDA, based on the submitted information and comparison to the predicate device.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
Not applicable. There was no "test set" for clinical performance that would require an adjudication method.
5. 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
Not applicable. This device is a total knee joint replacement prosthesis (a physical implant), not a diagnostic device or AI system that would involve human readers or AI assistance.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Not applicable. This device is a physical implant, not an algorithm.
7. The type of ground truth used (expert concensus, pathology, outcomes data, etc)
Not applicable to a clinical performance study. The "ground truth" in this regulatory context is the established safety and effectiveness profile of the predicate device, to which the new device is compared for equivalence.
8. The sample size for the training set
Not applicable. This is a physical medical device, not an algorithm that requires a training set.
9. How the ground truth for the training set was established
Not applicable. As above, this is a physical medical device, not an algorithm.
§ 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.