(63 days)
When a mechanical alignment approach is utilized, this device is indicated for patients with severe knee pain and disability due to:
- Rheumatoid arthritis, osteoarthritis, traumatic arthritis, polyarthritis.
- Collagen disorders, and/or avascular necrosis of the femoral condyle.
- Post-traumatic loss of joint configuration, particularly when there is patellofemoral erosion, dysfunction or prior patellectomy.
- Moderate valgus, varus, or flexion deformities.
- The salvage of previously failed surgical attempts or for a knee in which satisfactory stability in flexion cannot be obtained at the time of surgery.
When a kinematic alignment approach is utilized, this device is indicated for patients with severe knee pain and disability due to:
- Rheumatoid arthritis, osteoarthritis, traumatic arthritis, polyarthritis.
- Collagen disorders, and/or avascular necrosis of the femoral condyle.
- Moderate valgus, varus, or flexion deformities.
The kinematic alignment (KA) surgical technique may only be used with Persona CR femoral components, Persona CR or UC articular surface components, and cemented nonporous Persona tibial components without a stem extension.
Porous coated components may be used cemented (biological fixation). All other femoral, tibial baseplate, and all-polyethylene (UHMWPE and VEHXPE) patella components are indicated for cemented use only.
The Persona Personalized Knee System is a semiconstrained modular knee prosthesis designed to resurface the articulating surface of the femoral, tibial and patellar bones. With this submission, femoral components made from Titanium alloy (ASTM F136) that undergo the Ti-Nidium nitriding surface hardening treatment are being added to the system. These femoral components articulate against tibial and patellar articular surfaces to form a total knee system. This design is available in multiple sizing options to accommodate a wide range of anatomies. "Narrow" femoral components have a smaller M/L dimension than the "Standard" femoral components. This femoral component, when used with a CR or Medial Congruent (MC) articular surface, can accommodate a maximum active flexion of 155°, and with an Ultra Congruent (UC) articular surface, can accommodate a maximum active flexion of 145°. These femoral components are provided sterile and single use.
The provided text describes a 510(k) premarket notification for the "Persona® Personalized Knee System," a knee prosthesis. It focuses on demonstrating substantial equivalence to predicate devices, rather than proving a device meets specific performance acceptance criteria for an AI/ML algorithm.
Therefore, most of the requested information regarding acceptance criteria, sample sizes, ground truth establishment, expert adjudication, and MRMC studies for an AI/ML device is not applicable to this document.
The document explicitly states:
- Clinical Tests: "Clinical data was not deemed necessary for the subject device." This strongly indicates that performance metrics, such as those you'd establish for an AI/ML algorithm's accuracy or efficacy in a clinical setting, were not assessed for this submission.
- Purpose of Submission: The purpose is for "the addition of the Ti-Nidium cruciate retaining (CR) femoral components to the Persona Personalized Knee System." This is a hardware modification, not an AI/ML software submission.
- Basis for Substantial Equivalence: It's based on "Intended Use: Identical to predicates," "Indications for Use: Identical to predicate," "Materials: Similar to predicates," "Design Features: Identical to predicate," and "Sterilization: Identical to predicate." These are general device characteristics, not performance metrics for an intelligent system.
However, I can extract the non-clinical tests performed, which serve as the "proof" for the modified hardware component, albeit not in the context of AI/ML performance acceptance criteria.
Here's a breakdown of what can be inferred or directly stated from the provided document, even if it doesn't align with an AI/ML device's typical performance study criteria:
Acceptance Criteria and Study for Persona® Personalized Knee System (Hardware Modification):
Based on the provided FDA 510(k) summary, the device is a knee prosthesis, and the submission is for the addition of new components (Ti-Nidium cruciate retaining (CR) femoral components). The regulatory pathway chosen is substantial equivalence to existing predicate devices. This means that instead of defining novel performance acceptance criteria for a new type of device or AI/ML algorithm, the manufacturer needed to demonstrate that the modified device is as safe and effective as existing legally marketed devices, primarily through non-clinical (bench) testing.
The "acceptance criteria" here are implied by the successful completion of these non-clinical tests to demonstrate that the new component does not negatively impact the established safety and efficacy of the overall system when compared to predicates.
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Implied by Test Type) | Reported Device Performance (Summary) |
|---|---|
| Mechanical Durability/Integrity: | "Performance data and analyses demonstrate that: any differences do not raise new questions of safety and effectiveness; and the proposed device is at least as safe and effective as the legally marketed predicate devices." (General conclusion) |
| - Intercondylar (IC) notch deformation (Internal test method) | Not explicitly detailed, but presumably met internal standards to ensure structural integrity and prevent deformation. |
| - Posterior condyle fatigue (Internal test method) | Not explicitly detailed, but presumably met internal standards to ensure resistance to repeated stress. |
| Biocompatibility/Wear Performance: | |
| - Ti-Nidium femoral induced wear of ultra-high molecular weight polyethylene (UHMWPE) articular surfaces (per ISO 14243-3) | Not explicitly detailed, but the test was performed to assess adverse wear effects. Conclusion implies acceptable wear. |
| - Assessment of wear due to 3rd body particles during articulation | Not explicitly detailed, but the test was performed to assess resilience to wear in the presence of contaminants. Conclusion implies acceptable wear. |
| Imaging Compatibility: | |
| - Evaluation of the Persona Ti-Nidium Femur Components in the Magnetic Resonance Imaging (MRI) Environment | Not explicitly detailed, but presumably showed acceptable MRI compatibility (e.g., minimal artifact). |
| Sterility/Endotoxin Levels: | |
| - Bacterial Endotoxin Test (BET) per ANSI/AAMI ST 72:2011, demonstrating implants meet the limit of ≤20 Endotoxin units (EU)/Device per USP41-NF36 Chapter Medical Devices - Bacterial Endotoxin and Pyrogen Tests | Met the specified limit of ≤20 EU/Device. |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: Not specified in the document. For bench testing, sample sizes are typically determined by statistical power calculations or industry standards for the specific test (e.g., n=3 or n=5 for certain mechanical tests, or a larger number for wear tests).
- Data Provenance: The tests are "Non-Clinical Tests," meaning they were performed in a lab setting (benchtop testing), likely by the manufacturer (Zimmer, Inc.). There is no mention of country of origin for data as it's not patient data.
- Retrospective or Prospective: Not applicable, as this refers to patient data collection.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
- Not Applicable: This type of information (experts establishing ground truth) is relevant for studies involving qualitative assessments, diagnostic accuracy, or clinical endpoints adjudicated by medical professionals (e.g., radiologists, pathologists). For a knee prosthesis hardware modification, the "ground truth" is established by adherence to engineering specifications, material properties, and performance against established mechanical or sterility standards as measured by laboratory equipment.
4. Adjudication Method for the Test Set
- Not Applicable: Similar to point 3, adjudication methods are used to resolve disagreements among human reviewers (e.g., in reading medical images). Bench test results are quantitative measurements, not subject to human adjudication in the same way.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done
- No: The document explicitly states: "Clinical data was not deemed necessary for the subject device." Therefore, no MRMC study (which involves human readers/clinicians) was conducted or provided for this submission. The effect size of human readers improving with AI assistance is not relevant here as the device is a hardware implant, not an AI system.
6. If a Standalone (i.e. algorithm only without human-in-the loop performance) was done
- Not Applicable: This device is a physical knee prosthesis, not an algorithm.
7. The Type of Ground Truth Used
- Engineering Specifications and Standardized Test Methods: The "ground truth" for non-clinical tests is based on established engineering and materials science principles and validated test methods (e.g., ISO standards, internal validated methods). For example, a fatigue test's "ground truth" is whether the component fractured after a certain number of cycles, compared to a predefined acceptance limit. For the Bacterial Endotoxin Test, the ground truth is the measured Endotoxin Units per device staying below a specified limit.
8. The Sample Size for the Training Set
- Not Applicable: This refers to machine learning models. The Persona® Personalized Knee System is a medical device hardware.
9. How the Ground Truth for the Training Set was Established
- Not Applicable: This refers to machine learning models.
In summary, the provided document is a 510(k) clearance letter for a hardware modification to a knee prosthesis. The regulatory path chosen (510(k) based on substantial equivalence) and the type of data presented (non-clinical bench testing) are entirely different from the robust clinical and AI/ML performance studies that would require the detailed information you requested about acceptance criteria, human experts, and large datasets for training and testing AI algorithms.
§ 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.