(945 days)
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The Natural-Knee® Tibial Baseplates involve modifications to the original Natural-Knee® Tibial Baseplates. The modifications to the tibial resurfacing and stemmed baseplates involve the addition of a centrally located screw hole for optional enhanced insert/baseplate fixation. Furthermore, changes to the configuration of the porous coating pockets and increase in overall baseplate thickness were made to the resurfacing baseplate. The Natural-Knee® Baseplates are semi-constrained in design and both the medial and lateral ligaments must be intact. The tibial baseplates are part of the present Natural-Knee® System and mate with the same Natural-Knee® tibial inserts as the existing Natural-Knee® tibial baseplates. The inferior surface of the porous-coated baseplate is coated with Cancellous Structured Titanium (CSTi™).
The Natural-Knee All Poly Patella is designed to articulate with the Natural-Knee® Primary and Revision femoral components. It has a circular shape and is provided in 4 sizes and thicknesses of 7 and 10mm.
This appears to be a 510(k) summary for a medical device (Natural-Knee Tibial Baseplates and All Poly Patella), which typically focuses on demonstrating substantial equivalence to a predicate device rather than detailing specific clinical studies against acceptance criteria in the manner of a new drug or novel medical device approval pathway.
Therefore, many of the requested categories regarding "acceptance criteria" based on a study, "ground truth," "sample sizes," "expert qualification," and "MRMC studies" are not applicable in the context of this 510(k) submission.
Here's a breakdown of the relevant information from the provided text:
1. A table of acceptance criteria and the reported device performance
Based on the provided text, specific numerical acceptance criteria and reported device performance from a formal clinical study or human subject trial are not presented. The document instead refers to substantially equivalent performance to predicate devices and engineering analyses.
| Acceptance Criteria Category | Acceptance Criteria (Not explicitly stated numerically, but implied) | Reported Device Performance |
|---|---|---|
| Tibial Baseplates - Cantilever Fatigue Loading | Ability to withstand acceptable cantilever fatigue loading conditions (implied to be comparable to predicate devices) | "Results of an analysis indicated that the baseplate would withstand acceptable cantilever fatigue loading conditions." |
| Patella - Patello-femoral Contact Area | Patello-femoral contact area comparable to competitive all-poly patellas | "The results of these tests are comparable to competitive all poly patellas." |
| Patella - Lateral Subluxation | Lateral subluxation comparable to competitive all-poly patellas | "The results of these tests are comparable to competitive all poly patellas." |
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. The submission does not detail a clinical test set involving human subjects. The "analysis" of the tibial baseplate and "tests" of the patella likely refer to mechanical and bench testing, not human trials. Therefore, sample sizes for a patient test set, country of origin, and retrospective/prospective status are not provided or relevant in this context.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- Not Applicable. As no clinical test set for ground truth establishment is described, this information is not available.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
- Not Applicable. No clinical test set or adjudication process is described.
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 knee implant, not an AI or imaging diagnostic device. Therefore, MRMC studies are not relevant.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Not Applicable. This is a hardware medical device, not an algorithm.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
- For the Tibial Baseplates: The "ground truth" for the cantilever fatigue loading appears to be based on engineering standards and established mechanical testing protocols for similar devices, indicating "acceptable" performance.
- For the Patella: The "ground truth" for patello-femoral contact area and lateral subluxation tests is implicitly based on comparison to existing, legally marketed competitive all-poly patellas, implying that their performance defines the "ground truth" for acceptable function.
8. The sample size for the training set
- Not Applicable. This is a hardware 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, no training set data is relevant for this device.
Summary of the Study (Mechanical/Bench Testing):
The provided text describes mechanical and bench testing rather than clinical studies on human subjects to demonstrate the safety and effectiveness of the modified device.
- Tibial Components: An "analysis indicated that the baseplate would withstand acceptable cantilever fatigue loading conditions." This indicates a mechanical stress test was performed on the tibial baseplates. The "study" here is an engineering analysis and associated testing.
- Patella: "Patello-femoral contact area and lateral subluxation tests were performed." These are also bench tests designed to assess the functional characteristics of the patella component.
The overall approach for this 510(k) submission is to demonstrate substantial equivalence to predicate devices (Kirschner™ Performance™ Knee, Biomet AGC Knee, Howmedica P.C.A., Zimmer Miller-Galante Knee System for tibial components; Richards® Genesis Knee All-Poly Patellae for the patella) through design modifications and mechanical performance comparisons, rather than providing extensive clinical trial data against specific acceptance criteria for a novel device.
§ 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.