(189 days)
The NexFlex Total Knee System is indicated for:
- Painful, disabling joint disease resulting from rheumatoid arthritis, post-traumatic . arthritis, osteoarthritis, or degenerative arthritis
- . Failed osteotomies, unicompartmental replacement, or total knee replacement
- Post-traumatic loss of knee joint configuration and function .
- Moderate varus, valgus, or flexion deformity in which the ligamentous structures can . be returned to adequate function and stability
The NexFlex Total Knee System is intended for cemented use only.
The NexFlex Total Knee System consists of femoral components, tibial base components, tibial inserts, all-polyethylene tibial components, cancellous bone screws, a tibial screw hole cap, tibial stem extensions, and patellar components. The components of this system are designed to be used together and cannot be used as part of another system, nor can components of another system be incorporated into use with the NexFlex Total Knee System.
NexFlex femoral components are manufactured from cobalt-chromium alloy and are available in a range of sizes and in left and right orientations. They are available with or without a commercially pure titanium plasma sprayed inner surface.
Tibial base components are manufactured from titanium (Ti-6Al-4V) alloy and are available in a range of sizes. They are available with or without a commercially pure titanium plasma sprayed distal surface.
Tibial inserts are manufactured from ultra-high molecular weight polyethylene and are available in a range of sizes to match the tibial base components. The distal side of the tibial inserts has geometry to allow a mechanical lock to the tibial base components of corresponding size. The proximal side of the tibial inserts has geometry that allows articulation with the femoral components. Tibial inserts are available with two different proximal geometries, allowing for different amounts of constraint and contact area with the femoral components. A number of thicknesses of inserts are offered.
All-polyethylene tibial components are manufactured from ultra-high molecular weight polyethylene and are available in a range of sizes and thicknesses. These components have distal geometry similar to the tibial base components and proximal geometry similar to the tibial inserts.
Cancellous bone screws are manufactured from titanium (Ti-6Al-4V) alloy and are available in a range of lengths. The screws are designed to go through the tibial base component to secure it to the proximal tibia.
Tibial screw hole caps are manufactured from titanium (Ti-6Al-4V) alloy. They are designed to thread into the tibial base components to cover the screw holes when a cancellous bone screw is not used.
Tibial stem extensions are manufactured from titanium (Ti-6A1-4V) alloy and are available in a range of diameters and lengths. The stems are designed to mate with the tibial base components by means of a mechanical engagement.
Patellar components are manufactured from either ultra-high molecular weight polyethylene or a combination of ultra-high molecular weight polyethylene and titanium (Ti-6Al-4V) alloy. They are designed with posterior geometry that allows articulation with the femoral components. Patellar components with titanium backing have a commercially pure titanium plasma spraved anterior surface.
Here's an analysis of the provided text regarding the NexFlex Total Knee System, focusing on acceptance criteria and supporting studies:
Based on the provided 510(k) Summary for the NexFlex Total Knee System, the product is a medical device (a semi-constrained total knee prosthesis) submitted for premarket notification to the FDA. For such devices, acceptance criteria and studies typically focus on demonstrating substantial equivalence to legally marketed predicate devices, rather than establishing de novo performance metrics like sensitivity/specificity for a diagnostic AI. The "acceptance criteria" here implicitly refer to meeting the safety and effectiveness standards demonstrated by the predicate devices through mechanical testing and comparison of design, function, materials, and indications for use.
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Implicit) | Reported Device Performance (Summary) |
|---|---|
| Mechanical Strength & Durability (Withstanding in-vivo loading without failure) | "Mechanical testing of the NexFlex Total Knee System was performed in accordance with the recommended testing listed in the Draft Guidance... Testing indicated that the system is capable of withstanding in vivo loading without failure." |
| Material Biocompatibility | Implied by using materials (cobalt-chromium alloy, titanium alloy, ultra-high molecular weight polyethylene) found in predicate devices. |
| Design & Function Similarity | Explicitly stated: "similar to each of the listed predicate devices in one or more of the following areas: design, function..." |
| Indications for Use Similarity | Explicitly stated: "similar to each of the listed predicate devices in one or more of the following areas: ...and indications for use." |
2. Sample Size Used for the Test Set and Data Provenance
The provided 510(k) summary does not mention a clinical "test set" or data provenance in the context of human studies for performance or AI applications. The "testing" referred to is mechanical testing of the device itself.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
This information is not applicable to the provided document. The submission pertains to a knee prosthesis, not an AI/diagnostic device that would require expert-established ground truth from a test set of data.
4. Adjudication Method for the Test Set
This information is not applicable to the provided document for the same reasons as #3.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was Done
No, an MRMC comparative effectiveness study was not done, and this type of study is not relevant for a knee prosthesis 510(k) submission. These are typically for diagnostic devices, often involving AI.
6. If a Standalone (i.e. algorithm only, without human-in-the-loop performance) was Done
No, a standalone algorithm performance study was not done. The NexFlex Total Knee System is a physical medical device, not an algorithm or AI.
7. The Type of Ground Truth Used
The "ground truth" in this context is established by the performance of the predicate devices and the established safety and effectiveness of the materials and design principles used in total knee prostheses. For the mechanical testing, the "ground truth" is engineering standards and the ability to withstand simulated physiological loads without failure.
8. The Sample Size for the Training Set
This information is not applicable as the device is not an AI/algorithm and therefore does not have a "training set."
9. How the Ground Truth for the Training Set was Established
This information is not applicable for the same reasons as #8.
Summary of the Study that Proves the Device Meets Acceptance Criteria:
The study that proves the NexFlex Total Knee System meets its implicit acceptance criteria (which are primarily substantial equivalence to predicate devices and mechanical integrity) is described as "Non-Clinical Performance Data":
- Study Type: Mechanical testing.
- Methodology: Performed in accordance with the "recommended testing listed in the Draft Guidance for the Preparation of Premarket Notifications (510(k)s) for Cemented, Semi-Constrained Total Knee Prostheses." This guidance likely specifies various wear, fatigue, static strength, and other biomechanical tests relevant to knee implants.
- Results/Conclusion: "Testing indicated that the system is capable of withstanding in vivo loading without failure."
- Comparison: The results of these mechanical tests, coupled with the comparison of the NexFlex system's design, function, materials, and indications for use to the Miller/Gallante Total Knee System (Zimmer, Inc.), AGC Total Knee System (Biomet, Inc.), AMK Total Knee System (DePuy, a Johnson Company), and Series 7000 Total Knee System (Stryker/Osteonics), formed the basis for the FDA's determination of substantial equivalence. This determination effectively means the device meets the regulatory acceptance criteria for market entry.
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DEC - 8 1999
Image /page/0/Picture/1 description: The image shows the logo and name of a company called "Nexmed, Inc." along with the product name "NexFlex Total Knee System" and the text "Premarket Notification". The logo is a stylized letter "n" inside a circle. The text is in a serif font and is black in color. The image is likely from a document or advertisement for the company's knee replacement product.
510(k) Summary
510(k) Number
Manufacturer Identification
| Submitted By: | Nexmed, Inc.42-160 State StreetPalm Desert, CA 92211phone: (760) 779-8250fax: (760) 776-5527 |
|---|---|
| Contact Person: | Jason BlainManager of Product Development |
| Date Summary Prepared: | May 21, 1999 |
| Device Identification | |
| Proprietary Name: | NexFlex Total Knee System |
| Common Name: | Semi-constrained total knee prosthesis |
| Classification: | 21 CFR 888.3560: Prosthesis, Knee, Patellofemorotibial,Semi-constrained, Cemented, Polymer/Metal/Polymer |
Device Description
The NexFlex Total Knee System consists of femoral components, tibial base components, tibial inserts, all-polyethylene tibial components, cancellous bone screws, a tibial screw hole cap, tibial stem extensions, and patellar components. The components of this system are designed to be used together and cannot be used as part of another system, nor can components of another system be incorporated into use with the NexFlex Total Knee System.
NexFlex femoral components are manufactured from cobalt-chromium alloy and are available in a range of sizes and in left and right orientations. They are available with or without a commercially pure titanium plasma sprayed inner surface.
Tibial base components are manufactured from titanium (Ti-6Al-4V) alloy and are available in a range of sizes. They are available with or without a commercially pure titanium plasma sprayed distal surface.
Tibial inserts are manufactured from ultra-high molecular weight polyethylene and are available in a range of sizes to match the tibial base components. The distal side of the tibial inserts has geometry to allow a mechanical lock to the tibial base components of
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Image /page/1/Picture/0 description: The image shows a close-up of text, with the words "Premark" and "NexFlex" clearly visible. The text appears to be part of a larger document or label, possibly related to a product or company name. The font is a serif typeface, and the text is printed in black ink on a white background.
corresponding size. The proximal side of the tibial inserts has geometry that allows articulation with the femoral components. Tibial inserts are available with two different proximal geometries, allowing for different amounts of constraint and contact area with the femoral components. A number of thicknesses of inserts are offered.
All-polyethylene tibial components are manufactured from ultra-high molecular weight polyethylene and are available in a range of sizes and thicknesses. These components have distal geometry similar to the tibial base components and proximal geometry similar to the tibial inserts.
Cancellous bone screws are manufactured from titanium (Ti-6Al-4V) alloy and are available in a range of lengths. The screws are designed to go through the tibial base component to secure it to the proximal tibia.
Tibial screw hole caps are manufactured from titanium (Ti-6Al-4V) alloy. They are designed to thread into the tibial base components to cover the screw holes when a cancellous bone screw is not used.
Tibial stem extensions are manufactured from titanium (Ti-6A1-4V) alloy and are available in a range of diameters and lengths. The stems are designed to mate with the tibial base components by means of a mechanical engagement.
Patellar components are manufactured from either ultra-high molecular weight polyethylene or a combination of ultra-high molecular weight polyethylene and titanium (Ti-6Al-4V) alloy. They are designed with posterior geometry that allows articulation with the femoral components. Patellar components with titanium backing have a commercially pure titanium plasma spraved anterior surface.
Intended Use of the Device
The NexFlex Total Knee System is indicated for:
- Painful, disabling joint disease resulting from rheumatoid arthritis, post-traumatic . arthritis, osteoarthritis, or degenerative arthritis
- . Failed osteotomies, unicompartmental replacement, or total knee replacement
- Post-traumatic loss of knee joint configuration and function .
- Moderate varus, valgus, or flexion deformity in which the ligamentous structures can . be returned to adequate function and stability
The NexFlex Total Knee System is intended for cemented use only.
Substantial Equivalence
The NexFlex Total Knee System is substantially equivalent to the following knee systems: Miller/Gallante Total Knee System (Zimmer, Inc.), AGC Total Knee System (Biomet, Inc.), AMK Total Knee System (DePuy, a Johnson Company), Series 7000 Total Knee System (Stryker/Osteonics). The NexFlex Total Knee System is
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similar to each of the listed predicate devices in one or more of the following areas: design, function, materials used, and indications for use.
Non-Clinical Performance Data
Mechanical testing of the NexFlex Total Knee System was performed in accordance with the recommended testing listed in the Draft Guidance for the Preparation of Premarket Notifications (510(k)s) for Cemented, Semi-Constrained Total Knee Prostheses. Testing indicated that the system is capable of withstanding in vivo loading without failure.
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Image /page/3/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a stylized caduceus symbol, which is a staff with two snakes coiled around it, representing medicine and healing. The text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" is arranged in a circular pattern around the caduceus symbol.
Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850
DEC - 8 1999
Mr. Jason Blain Manager of Product Development Nexmed Incorporated 42-160 State Street Palm Dessert. California 92211
Re: K991882 Trade Name: NexFlex Total Knee System Regulatory Class: II Product Codes: JHW Dated: May 28, 1999 Received: June 2, 1999
Dear Mr. Blain:
We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.
If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the current Good Manufacturing Practice requirement, as set forth in the Quality System Regulation (QS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic (QS) inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or regulations.
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Page 2 - Mr. Blain
This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits vour device to proceed to the market.
If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4659. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its internet address "http://www.fda.gov/cdrh/dsmamain.html".
An
Sincerely yours,
James E. Dillard III
Acting Director Division of General and Restorative Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
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Indications for Use
510(k) Number: K991882
Device Name: NexFlex Total Knee System
Indications for Use:
- Painful, disabling joint disease resulting from rheumatoid arthritis, post-traumatic . arthritis, osteoarthritis, or degenerative arthritis
- Failed osteotomies, unicompartmental replacement, or total knee replacement ●
- Post-traumatic loss of knee joint configuration and function .
- Moderate varus, valgus, or flexion deformity in which the ligamentous structures can ◆ be returned to adequate function and stability
The NexFlex Total Knee System is intended for cemented use only.
thut Clurde
(Division Sign-Off)
(Division Sign Division of General Restorative Devices K99188 510(k) Number
Prescription Use
X
(Per 21 CFR 801.109)
Over-the-Counter Use_
§ 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.