(69 days)
The P.F.C. Sigma Porous Modular Keel Tibial Tray is indicated for use in total knee replacements of patients suffering from severe pain and disability due to permanent structural damage in the knee joint from rheumatoid arthritis, osteoarthritis, post-traumatic arthritis, collagen disorders, or pseudogout. This damage may also be the result of trauma or failed prior surgical intervention.
In accordance with Federal (USA) requirements, the P.F.C. Sigma Knee Modular Keel Tibial Tray is indicated for use only with PMMA bone cement.
The P.F.C. Sigma Porous Modular Keel Tibial Tray is manufactured from titanium alloy (Ti-6Al-4V). The distal surface, including approximately one-third of the stem and P.F.C. Sigma Porous Modular Keel Tibial Tray portions, is coated with commercially pure titanium porous coating to enhance cement fixation. If additional fixation is required, the tibial tray is designed with four screw holes that accept bone screws.
The distal tip of the P.F.C. Sigma Porous Modular Keel Tibial Tray is manufactured with a UHMWPE plug. When a long stem device is required the UHMWPE plug is removed to allow the tibial tray to accept attachment of a metallic extension.
The P.F.C. Sigma Porous Modular Keel Tibial Tray is designed for use with both P.F.C. Modular and P.F.C. Sigma tibial inserts, including curved posterior lipped and stabilized.
The provided text describes a 510(k) summary for a medical device called the "P.F.C. Sigma Porous Modular Keel Tibial Tray." It primarily focuses on the device's description, indications for use, and a demonstration of substantial equivalence to previously marketed devices. This type of submission (510(k)) does not typically include a detailed "study" in the sense of a clinical trial with acceptance criteria and reported performance in the manner one might expect for a novel drug or a high-risk medical device with complex performance metrics.
Instead, the "acceptance criteria" and "study" for a Class II knee prosthesis like this, under a 510(k) pathway, usually revolve around demonstrating substantial equivalence to a predicate device. This is achieved through:
- Bench Testing/Performance Testing: To ensure the device meets established engineering and material standards for safety and function.
- Material Equivalence: Demonstrating that the materials used are common, well-characterized, and equivalent to those used in the predicate.
- Design Equivalence: Showing that the design principles and features are substantially similar to the predicate.
- Sterilization and Packaging Equivalence: Ensuring these aspects are comparable to established methods.
Therefore, the "acceptance criteria" are generally compliance with recognized standards and demonstration of equivalence, rather than specific sensitivity/specificity thresholds or clinical outcomes from a human study.
Here's a breakdown of the requested information based on the provided document:
Acceptance Criteria and Study for P.F.C. Sigma Porous Modular Keel Tibial Tray
The "acceptance criteria" and "study" for this device are framed within the context of a 510(k) submission, which aims to demonstrate substantial equivalence to a legally marketed predicate device rather than presenting a de novo clinical study with pre-defined performance thresholds like those seen in diagnostic AI.
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria for a 510(k) submission of this nature are not typically expressed as a table of clinical performance metrics (e.g., sensitivity, specificity) but rather as adherence to recognized standards and demonstration of equivalence to existing devices.
| Acceptance Criteria Category | Specific Criteria | Reported Device Performance/Evidence Provided |
|---|---|---|
| Intended Use | The device is indicated for use in total knee replacements for severe pain and disability due to permanent structural damage (rheumatoid arthritis, osteoarthritis, post-traumatic arthritis, collagen disorders, pseudogout, trauma, failed prior surgical intervention). It must be used only with PMMA bone cement. | The P.F.C. Sigma Porous Modular Keel Tibial Tray is described with this specific Indication for Use statement, which is identical or highly similar to its predicate devices, affirming its intended purpose. The FDA's response explicitly states this letter will allow you to begin marketing your device as described in your 510(k) premarket notification immediately. |
| Material Equivalence | Materials of construction (titanium alloy, porous coating, UHMWPE plug) must be biologically compatible and functionally equivalent to predicate devices. | Manufactured from titanium alloy (Ti-6Al-4V) with commercially pure titanium porous coating and a UHMWPE plug. These materials are commonly used in knee prostheses and are considered equivalent to those used in the cited predicate devices (e.g., K892394, K961685, K923807, K864671, K961379). |
| Design Equivalence | Design features (e.g., modularity, keel, porous coating, screw holes for fixation, compatibility with inserts) must be substantially similar in principle to predicate devices, ensuring comparable mechanical function and clinical performance. | The device features a porous modular keel design, four screw holes for additional fixation, a removable UHMWPE plug for stem extension, and compatibility with P.F.C. Modular and P.F.C. Sigma tibial inserts. These design elements are demonstrated to be "substantially equivalent in terms of [...] design" to the predicate devices listed. The reference to "P.F.C. Sigma tibial inserts, including curved posterior lipped and stabilized" further shows design compatibility within the system. |
| Performance Testing | Device must meet relevant voluntary performance standards (e.g., ASTM standards) for mechanical strength, fatigue, fixation, and other relevant properties to ensure safe and effective performance. | The determination of substantial equivalence was based on "performance testing and conformance with voluntary performance standards. e.g. ASTM F-1580, ASTM F620 and ASTM F1044." This indicates mechanical and material tests were conducted to demonstrate compliance with these established standards for implantable medical devices. |
| Sterilization & Packaging | Method of sterilization (not explicitly stated but implied to be standard for implants) and packaging must ensure sterility and device integrity until use, comparable to predicate devices. | The summary states the device is "substantially equivalent in terms of [...] sterilization method, and packaging" to the predicate devices, implying these aspects meet established industry and regulatory requirements. |
| Labeling | Labeling must clearly state indications for use, contraindications, and any specific requirements (e.g., "for cemented use only"). Must comply with general control provisions (annual registration, listing, GMP, misbranding, adulteration). | The FDA letter explicitly mandates: "This device may not be labeled or promoted for non-cemented use." and "All labeling for this device...must prominently state that the device is intended for cemented use only." This demonstrates that the labeling requirements (acceptance criteria) were identified and addressed as a condition of clearance. The general control provisions are also explicitly mentioned in the FDA letter. |
2. Sample Size Used for the Test Set and Data Provenance
For a 510(k) submission for a knee prosthesis, especially one demonstrating substantial equivalence through bench testing, there isn't a "test set" in the clinical trial sense with human patients. Instead, the "test set" refers to the number of devices or material samples subjected to the specified performance tests.
- Sample Size for Test Set: Not explicitly stated in the provided document. The ASTM standards (F-1580, F620, F1044) cited would specify the minimum number of samples required for each particular test (e.g., fatigue, tensile strength, shear strength).
- Data Provenance: The "study" here is primarily bench testing conducted by the manufacturer (DePuy Orthopaedics, Inc.) according to recognized industry standards. This data would be generated in a laboratory setting, likely within the United States (where the manufacturer is based), and is inherently a prospective generation of data for the submission.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
This question is not applicable to this type of 510(k) submission. "Ground truth" established by human experts is typically relevant for diagnostic devices or AI algorithms where the device's output is compared against expert interpretation of medical images or patient conditions. For a knee prosthesis whose clearance is based on substantial equivalence and performance testing to engineering standards, human expert "ground truth" for the test set is not a component of the submission described here.
4. Adjudication Method for the Test Set
Not applicable. As noted above, there isn't a clinical "test set" requiring expert adjudication for this 510(k) submission. The "adjudication" for the performance testing would be the interpretation of the physical test results against the pass/fail criteria defined by the ASTM standards.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study Was Done
No. An MRMC study is a type of clinical study typically used for diagnostic devices (especially imaging-based ones) to compare reader performance with and without AI assistance. This 510(k) submission is for an implantable knee prosthesis, not a diagnostic device, and therefore such a study was not performed or necessary for its clearance.
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 or AI system.
7. The Type of Ground Truth Used
The "ground truth" in this context refers to the established scientific and engineering principles and standards that underpin the safety and effectiveness of implantable devices. This includes:
- Material properties: Measured values meeting specified ranges (e.g., tensile strength, fatigue life).
- Biocompatibility: Demonstrated non-toxicity and long-term acceptance by the body through established testing and material history.
- Mechanical performance: Ability to withstand physiological loads and stresses as tested against ASTM or similar standards.
- Clinical history of predicate devices: The safety and efficacy of the substantially equivalent predicate devices effectively serve as the "ground truth" for the clinical utility of the device in question.
8. The Sample Size for the Training Set
Not applicable. This device does not involve a "training set" in the context of machine learning or AI.
9. How the Ground Truth for the Training Set Was Established
Not applicable. As there is no training set, this question is not relevant.
In summary: The provided 510(k) summary and FDA clearance letter detail a process of demonstrating substantial equivalence for an implantable medical device. The "acceptance criteria" revolve around meeting established engineering standards and showing comparability to already-cleared predicate devices, rather than clinical performance metrics from a human study. The "study" primarily consists of bench testing, not clinical trials or AI algorithm validation.
§ 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.