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), and moderate valgus, varus, or flexion deformities. The salvage of previously failed surgical attempts if the knee can be satisfactorily balanced and stabilized at the time of surgery. This device is intended for cemented use only Specific uses with CR-Flex femorals: Provides increased flexion capability for patients who have both the flexibility and desire to increase their flexion range. The CR-Flex femoral is designed for use with a functional posterior cruciate ligament and when load bearing range of motion (ROM) is expected to be less than or equal to 155 degrees.

Device Description

The NexGen CR-Flex femoral components are part of the Zimmer Flex-series of semiconstrained, nonlinked condylar knee prostheses that are designed to have a maximum active flexion of 155 degrees. Except for modifications to allow flexion to 155 degrees, CR-Flex femoral components are identical to the predicate device. The modifications do not change the intended use or the fundamental scientific technology. The device is packaged and sterilized using the same materials and processes

AI/ML Overview

Here's an analysis of the provided text, focusing on the acceptance criteria and study information:

Acceptance Criteria and Device Performance

The provided document describes a device modification for the NexGen® Complete Knee Solution Cruciate Retaining (CR)-Flex Femoral Components. As such, the acceptance criteria are primarily focused on demonstrating substantial equivalence to existing predicate devices rather than establishing new independent performance benchmarks.

Acceptance Criteria (Implied)	Reported Device Performance
Safety and Effectiveness (equivalent to predicate devices)	"Performance testing completed as part of the design assurance procedure demonstrated that this device is safe and effective and substantially equivalent to the predicate device."
Functional Equivalence (modifications do not change intended use or fundamental scientific technology)	"Except for modifications to allow flexion to 155 degrees, CR-Flex femoral components are identical to the predicate device. The modifications do not change the intended use or the fundamental scientific technology."
Manufacturing Process Equivalence (packaging and sterilization)	"The device is packaged and sterilized using the same materials and processes"
Indications for Use (maintain or expand without significant change)	The listed indications for use are consistent with those of total knee prostheses. The specific uses for CR-Flex femorals, such as "Provides increased flexion capability" and "when load bearing range of motion (ROM) is expected to be less than or equal to 155 degrees," are presented as enhancements within the existing scope, not fundamental changes.

Study Details

Sample size used for the test set and the data provenance:
- Test Set Sample Size: Not explicitly stated for a clinical test set. The document indicates "Performance testing completed as part of the design assurance procedure," which implies an engineering/bench test. There is no mention of a patient-based test set or its size.
- Data Provenance: The document does not specify a country of origin for any data. The study is non-clinical (bench testing), so the concept of retrospective or prospective data from patients does not apply.
Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Not applicable. This was a non-clinical performance study.
Adjudication method for the test set:
- Not applicable. This was a non-clinical performance study.
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:
- No. This is a medical device (knee implant), not an AI diagnostic tool.
If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Not applicable. This is a medical device (knee implant), not an algorithm.
The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- The "ground truth" for this device modification was based on engineering performance specifications and design principles to ensure "safe and effective and substantially equivalent" performance to the predicate devices. This would involve mechanical testing for attributes like wear, strength, and range of motion, rather than clinical ground truth from patients.
The sample size for the training set:
- Not applicable. This is a medical device for which the submission relies on non-clinical performance testing and substantial equivalence to predicate devices, not machine learning model training.
How the ground truth for the training set was established:
- Not applicable. See point 7.

Summary

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Summary of Safety and Effectiveness

	OCT 1 7 2002
Submitter:	Zimmer, Inc.P.O. Box 708Warsaw, IN 46581-0708
Contact Person:	Stephen H. McKelveyManager, Regulatory AffairsTelephone: (574) 372-4944Fax: (574) 372-4605
Date:	September 23, 2002
Trade Name:	NexGen® Complete Knee Solution CruciateRetaining (CR)-Flex Femoral Components
Common Name:	Total Knee Prosthesis
Classification Nameand Reference:	Knee joint patellofemorotibial polyethylene/metal/polyethylene semiconstrained cemented totalknee prosthesis - 21 CFR § 888.3560
Predicate Devices:	NexGen CR knee, manufactured by Zimmer,K933785, cleared January 30, 1995 and the NexGenLPS-Flex knee, manufactured by Zimmer,K991581, cleared July 30, 1999.
Device Description:	The NexGen CR-Flex femoral components are partof the Zimmer Flex-series of semiconstrained,nonlinked condylar knee prostheses that aredesigned to have a maximum active flexion of 155degrees.
Intended Use:	This device is indicated for:
	Patients with severe knee pain and disability dueto rheumatoid arthritis, osteoarthritis, traumaticarthritis, polyarthritis, collagen disorders and/oravascular necrosis of the femoral condyle, post-traumatic loss of joint configuration(particularly when there is patellofemoralerosion, dysfunction, or prior patellectomy), andmoderate valgus, varus, or flexion deformities.

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Special 510(k): Device Modification

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The salvage of previously failed surgical attempts if the knee can be satisfactorily balanced and stabilized at the time of surgery.
This device is intended for cemented use only

Specific uses with CR-Flex femorals:

-Provides increased flexion capability for patients who have both the flexibility and desire to increase their flexion range.
-The CR-Flex femoral is designed for use with a functional posterior cruciate ligament and when load bearing range of motion (ROM) is expected to be less than or equal to 155 degrees.

Except for modifications to allow flexion to 155 degrees, CR-Flex femoral components are identical to the predicate device. The modifications do not change the intended use or the fundamental scientific technology. The device is packaged and sterilized using the same materials and processes

Performance Data (Nonclinical and/or Clinical):

Comparison to Predicate Device:

Non-Clinical Performance and Conclusions:

Performance testing completed as part of the design assurance procedure demonstrated that this device is safe and effective and substantially equivalent to the predicate device.

Clinical Performance and Conclusions:

Clinical data and conclusions were not needed for this device.

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DEPARTMENT OF HEALTH & HUMAN SERVICES

Image /page/2/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a stylized eagle with three stripes forming its body and wing. The eagle is encircled by the text "DEPARTMENT OF HEALTH & HUMAN SERVICES • USA" arranged in a circular fashion around the bird.

Public Health Service

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

Mr. Stephen H. McKelvey Manager, Regulatory Affairs Zimmer, Inc. P.O. Box 708 Warsaw, Indiana 46581-0708

Re: K023211

Trade/Device Name: NexGen® Complete Knee Solution Cruciate Retaining Flex Femoral Component

Regulation Number: 888.3560

Regulation Name: Knee joint patellofemorotibial polymer/metal/polymer, semi-constrained Cemented prosthesis

Regulatory Class: II Product Code: JWH Dated: September 23, 2002 Received: September 26, 2002

Dear Mr. McKelvey:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate 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) that do not require approval of a premarket approval application (PMA). 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 vour device is classified (see above) into either class II (Special Controls) or class III (PMA), 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 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or anv Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807): labeling (21 CFR Part 801); good manufacturing practice requirements as set forth in the quality systems (OS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

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Page 2 - Mr. Stephen H. McKelvey

This letter will allow you to begin marketing your device as described in your Section 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 your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 21 CFR Part 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4649. 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" (21CFR Part 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html

Sincerely yours,

Mark N Mikkelsen

Celia M. Witten, Ph.D., M.D. Director Division of General, Restorative and Neurological Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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Indications for Use

Page 1 of 1

510(k) Number (if known):

Device Name:

NexGen® Complete Knee Solution Cruciate Retaining (CR)-Flex Femoral Components

Indications for Use:

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, posttraumatic loss of joint configuration (particularly when there is patellofemoral erosion, dysfunction, or prior patellectomy), and moderate valgus, varus, or flexion deformities.
The salvage of previously failed surgical attempts if the knee can be satisfactorily balanced and stabilized at the time of surgery.

This device is intended for cemented use only

Specific uses with CR-Flex femorals:

Provides increased flexion capability for patients who have both the flexibility and desire to increase their flexion range.
The CR-Flex femoral is designed for use with a functional posterior cruciate ligament and when load bearing range of motion (ROM) is expected to be less than or equal to 155 degrees.

(Please do not write below this line - Continue on another page if needed)

Concurrence of CDRH, Office of Device Evaluation (ODE)

Ma
n
(Division Sign-Off)
Division of General, Restorative
and Neurological Devices
510(k) Number __ K023211

Prescription Use (Per 21 CFR 801.109) OR

Over-The-Counter Use (Optional Format 1-2-96)

Regulation Number and Section

§ 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.