(38 days)
The Sigma PS Femoral Components are intended for cemented use as the femoral components of a Total Knee Replacement system.
Candidates for total knee replacement include elderly patients with a severely painful and/or severely disabled joint resulting from osteoarthritis, post-traumatic arthritis, rheumatoid arthritis, or a failed previous implant. Total knee replacement may be considered for younger patients if, in the opinion of the surgeon, an unequivocal indication for total knee replacement outweighs the risks associated with the age of the patient, and if limited demands regarding activity and knee joint loading can be assured. This includes severely crippled patients with multiple joint involvement for whom a gain in knee mobility may lead to significant improvement in their quality of life.
The Sigma PS Femoral Components are part of the Sigma Total Knee Replacement System. They are Co-Cr-Mo alloy cruciate substituting femoral components with an asymmetric trochlear groove, available in sizes 1.5 to 6, in right and left versions. The Sigma PS Femoral Components are available with or without lugs (pegs) on the fixation surface. The femoral components incorporate an intercondylar box and bolt hole, which allow the attachment of optional femoral stems for additional stability. The Sigma PS Femoral Components (without lugs) allow for the attachment of modular augments on the distal and posterior fixation surfaces. Fixation of the femoral component to the femur is achieved using bone cement.
The provided document is a 510(k) premarket notification for a medical device, specifically the DePuy Sigma PS Femoral Components, a part of a Total Knee Replacement system. This type of submission focuses on demonstrating substantial equivalence to a legally marketed predicate device rather than fulfilling specific performance-based acceptance criteria through a clinical study or extensive performance testing as would be seen in a PMA (Premarket Approval) application.
Therefore, many of the typical elements of a study that prove a device meets acceptance criteria (like sample size for test sets, ground truth establishment, MRMC studies, standalone performance, etc.) are not applicable in this context. The basis for substantial equivalence is primarily focused on design, materials, manufacturing, and preclinical testing (dimensional comparisons, fatigue testing, and patellofemoral contact area analysis), rather than clinical performance metrics in humans.
Here's a breakdown based on the information available:
1. Table of acceptance criteria and the reported device performance
| Acceptance Criteria (Related to Substantial Equivalence Basis) | Reported Device Performance / Assessment |
|---|---|
| Indications for Use Alignment: Intended for cemented use as femoral components of a Total Knee Replacement system, for conditions like osteoarthritis, post-traumatic arthritis, rheumatoid arthritis, or failed previous implants. | The device's intended use and indications for use are identical or highly similar to the predicate devices (Darwin Knee System (K950010) and PFC Sigma Knee System (K971189)). |
| Design Similarity: Cruciate substituting femoral components with asymmetric trochlear groove, available in sizes 1.5-6, with/without lugs, Co-Cr-Mo alloy, intercondylar box and bolt hole for optional stems, modular augments allowed. | The device is described as a "modification of the Sigma Femoral Components that were previously cleared." The design features (Co-Cr-Mo alloy, cruciate substituting, asymmetric trochlear groove, sizes, right/left, with/without lugs, intercondylar box/bolt hole) are the same as or minor modifications of the predicate devices. |
| Material Similarity: Co-Cr-Mo alloy. | The device uses Co-Cr-Mo alloy, which is the same as the predicate devices. |
| Method of Manufacture Similarity. | The submission asserts similarity in the method of manufacture as a basis for substantial equivalence. No specific details about the manufacturing process or acceptance criteria for manufacturing are provided in this summary. |
| Performance - Dimensional Comparisons. | Dimensional comparisons were conducted to demonstrate similarity to the predicate devices, though specific criteria or results are not detailed in this summary. This is a common preclinical assessment for orthopedic implants to ensure fit and function within expected parameters. |
| Performance - Fatigue Testing. | Fatigue testing was conducted to assess the mechanical durability and longevity of the device, implying that the device met acceptable standards for this type of implant. Specific acceptance criteria (e.g., cycles to failure, load levels) or results are not detailed in this summary, but the conclusion is that it supports substantial equivalence. |
| Performance - Patellofemoral Contact Area Analysis. | Patellofemoral contact area analysis was performed. This is crucial for knee implants to ensure proper articulation and minimize wear and stress on the patella. The results of this analysis contributed to the determination of substantial equivalence, implying acceptable contact mechanics. Specific criteria or results are not detailed in this summary. |
Study Details (Not applicable for a 510(k) "substantial equivalence" claim based on design and preclinical testing):
This submission is a 510(k), which demonstrates "substantial equivalence" to a predicate device rather than showing de novo safety and effectiveness through clinical trials with specific performance endpoints. Therefore, many of the typical elements requested in the prompt for a clinical study are not present or relevant:
- 2. Sample size used for the test set and the data provenance: Not applicable. The "test set" here refers to preclinical tests (dimensional, fatigue, patellofemoral contact). No human clinical test set is described.
- 3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts: Not applicable. Ground truth for preclinical engineering tests is based on established engineering principles and standards, not expert consensus in the clinical sense.
- 4. Adjudication method for the test set: Not applicable.
- 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 is not an AI/diagnostic device.
- 6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done: Not applicable. This is not an AI/algorithm device.
- 7. The type of ground truth used (expert consensus, pathology, outcomes data, etc): For preclinical tests, the "ground truth" is derived from established engineering test methods and standards (e.g., ISO, ASTM for fatigue testing).
- 8. The sample size for the training set: Not applicable. There is no training set in the context of device development for a 510(k) clearance based on substantial equivalence through design and preclinical testing.
- 9. How the ground truth for the training set was established: Not applicable.
In summary: The "study" described in the 510(k) is a comparison to predicate devices and involves preclinical engineering assessments (dimensional comparisons, fatigue testing, patellofemoral contact area analysis) to demonstrate that the modified device performs similarly and is as safe and effective as the previously cleared devices. It is not a clinical trial with human subjects, nor does it involve AI/reader performance metrics.
§ 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.