Relief of pain and restoration of knee function following the effects of osteo-, rheumatoid and inflammatory arthritis, post-trauma disease effects, avascular necrosis, and total knee revision with or without varus, valgus or flexion deformity.

The tibial and femoral components are intended for use only with bone cement.

Device Description

The devices which are the subject of this submission constitute a line extension to the previously cleared Nuffield Total Knee System which has been on the market since 1989.

This submission addresses those Nuffield Total Knee System devices which are plasma sprayed.

The devices restore knee function in patients with degenerative rheumatoid or osteoarthritis, and are suitable for primary arthroplasty or revision surgery.

The plasma coated devices which are the subject of this submission are:

i. NTK Femurs (stemmed, stem-less and pegged)
NTK Tibias (stemmed) ii.
iii. Patellas

These devices are used in conjunction with previously cleared NTK devices, ie UHMPE Tibial Inserts, all-UHMWPE Tibias and Patellas.

The devices which are the subject of this submission are manufactured from cobalt-chrome alloy and are plasma sprayed; the plasma coating provides an increased surface roughness to act as a key for mechanical interlock with PMMA Bone Cement.

Although the Nuffield Total Knee is designed to spare the posterior cruciate ligament, the stability of the replacement relies on neither the anterior cruciate ligament and the devices can be used when both ligaments are absent.

The Plasma Coated Nuffield Total Knee System is intended for use ONLY with bone cement.

AI/ML Overview

This document is a 510(k) summary for the Nuffield Total Knee System and primarily focuses on establishing substantial equivalence to previously marketed devices. It does not contain the kind of detailed information about acceptance criteria, specific performance metrics, or study designs that would be used to prove a device meets those criteria, as typically found in a clinical trial report or a more comprehensive technical submission.

The document discusses mechanical test data as support for safety and effectiveness, and mentions clinical use outside the United States for eight years with no post-operative problems reported. However, it does not provide the specifics needed to complete the requested table and study details.

Therefore, I cannot fulfill your request for:

A table of acceptance criteria and reported device performance: This document states the device is "substantially equivalent" based on material, design principles, and intended use, but it does not specify quantitative acceptance criteria or performance metrics (e.g., success rates, complication rates, implant survival rates with thresholds).
Sample size used for the test set and data provenance: The document mentions "extensive mechanical test data" but provides no details on sample sizes or specific tests conducted. For clinical use, it mentions "eight years" of use outside the US but does not specify a patient sample size or the countries of origin for this data.
Number of experts used to establish ground truth and qualifications: This information is not present.
Adjudication method: This information is not present.
MRMC comparative effectiveness study: This document does not discuss such a study or any effect size related to AI assistance, as the device is a knee implant, not an AI-powered diagnostic tool.
Standalone algorithm performance: This is not applicable to a knee implant.
Type of ground truth used: For mechanical tests, the ground truth would be physical measurements. For clinical use, it would be patient outcomes, but no details on how this was assessed are provided.
Sample size for the training set: Not applicable, as this is not an AI/ML device.
How ground truth for the training set was established: Not applicable.

However, I can extract the following relevant information about the basis for clearance from the provided text:

Basis for Substantial Equivalence and Safety/Effectiveness (as presented in the document):

Predicate Devices: Duracon Knee System (Howmedica, US since 1993) and Nuffield Total Knee System (Corin Medical, US since 1993).
Reasons for Substantial Equivalence:
- All are four-part knees utilizing cobalt chrome alloy femoral and tibial components, ultra high molecular weight polyethylene tibial inserts, and metal-backed/all-polyethylene patella components.
- All components have a range of sizes and differing thicknesses of polyethylene.
- All are designed for cemented use ONLY.
- All contain within the range an all-polyethylene monoblock tibial component for low demand patients.
Evidence for Safety and Effectiveness (General Mention):
- "extensive mechanical test data confirming the devices' safety and effectiveness." (No specific criteria or results provided in this summary).
- "The Plasma Coated Nuffield Total Knee System has been in clinical use outside the United States for eight years and no post-operative problems have been reported." (No specific study details, sample size, or follow-up duration provided).

In summary, this 510(k) document is a declaration of intent to market and a rationale for substantial equivalence. It does not provide the detailed study results and acceptance criteria typically found in reports designed to prove a device meets specific performance criteria through a rigorous study, especially in the context of AI/ML or comparative clinical trials.

Summary

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K9805215

APR 2 9 1998

510(k) SUMMARY

Name of Company: Corin Medical Ltd The Corinium Centre Cirencester Gloucestershire GL7 1 YJ United Kingdom

The Nuffield Total Knee System Name of Device:

The devices which are the subject of this submission constitute a line Device Description: extension to the previously cleared Nuffield Total Knee System which has been on the market since 1989.

This submission addresses those Nuffield Total Knee System devices which are plasma sprayed.

The devices restore knee function in patients with degenerative rheumatoid or osteoarthritis, and are suitable for primary arthroplasty or revision surgery.

The plasma coated devices which are the subject of this submission are:

i. NTK Femurs (stemmed, stem-less and pegged)
NTK Tibias (stemmed) ii.
iii. Patellas

These devices are used in conjunction with previously cleared NTK devices, ie UHMPE Tibial Inserts, all-UHMWPE Tibias and Patellas.

The Plasma Coated Nuffield Total Knee System is intended for use ONL Y with bone cement.

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Image /page/1/Picture/0 description: The image shows a handwritten string of characters, which appears to be a combination of letters and numbers. The string reads 'K9805215'. The characters are written in a slightly rough, uneven style, suggesting they were written quickly or with a writing instrument that doesn't produce a perfectly smooth line. The image is in black and white.

SAFETY AND SUBSTANTIAL EQUIVALENCE AND SUMMARY OF EFFECTIVENESS

The Plasma Coated Nuffield Total Knee System is substantially equivalent to both the Duracon Knee System, promoted by Howmedica in the US since 1993, and the Nuffield Total Knee System, promoted in the US by Corin Medical since 1993. The reasons for this are summarised below:

All are four-part knees utilising cobalt chrome alloy femoral and tibial components, ત. ultra high molecular weight polyethylene tibial inserts and metal-backed and allpolyethylene patella components.
b. All components have a range of sizes and differing thicknesses of polyethylene.
All are designed for cemented use ONLY. C.
d. All contain within the range an all-polyethylene monoblock tibial component for low demand patients.

This submission is supported by extensive mechanical test data confirming the devices' safety and effectiveness. The Plasma Coated Nuffield Total Knee System has been in clinical use outside the United States for eight years and no post-operative problems have been reported.

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Image /page/2/Picture/1 description: The image shows the logo for the Department of Health & Human Services - USA. The logo is circular, with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" arranged around the perimeter. In the center of the circle is an abstract image of a person.

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

Mr. Craig Corrance ·President Corin U.S.A. 10500 University Center Drive Suite 190 Tampa, Florida 33612

Re : K980545 The Nuffield Total Knee System (Ti Plasma Spray) Requlatory Class: II Product Code: JWH Dated: February 2, 1998 February 12, 1998 Received:

Dear Mr. Corrance:

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 This decision is based on Food, Drug, and Cosmetic Act (Act). this device being equivalent only to similar devices labeled and intended to be fixed within bone with acrylic "bone cement." You may, therefore, market your device subject to the general controls provisions of the Act and the following limitations:

This device may not be labeled or promoted for non-1. cemented use.
1. All labeling for this device, including package label and labeling included within the package, must prominently state that the device is intended for cemented use only.
Any non-cemented fixation of this device is considered 3. investigational and may only be investigated as a siqnificant risk device in accordance with the investigational device exemption (IDE) regulation under 21 CFR, Part 812. All users of the device for noncemented fixation must receive approval from their respective institutional review boards (IRBs) and the Food and Druq Administration (FDA) to conduct the investigation.

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Page 2 - Mr. Craig Corrance

The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practices, 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 Requlations, 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 (OS) inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory -------In addition, FDA may publish further announcements action. concerning your device in the Federal Reqister. 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 Requlations.

This letter will allow you to begin marketing your device as described in your 510(k) premarket notification immediately. An FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and 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 809.10 for in vitro diaqnostic 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

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Page 3 - Mr. Craig Corrance

obtained from the Division of Small Manufacturers Assistance obtained from the Divibion or 6mm-2041 or (301) 443-6597 or at at Ics Coll Free nambor (6:5)/www.fda.gov/cdrh/dsmamain.html".

Sincerely yours,

focalefa

Celia M. Witten, Ph.D., M.D.
Director
Division of General and
Restorative Devices
Office of Device Evaluation

Center for Devices and Radiological Health

Enclosure

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510(k) Number (if known):

K980545

Device Name:

The Nuffield Total Knee System

INDICATIONS FOR USE

The tibial and femoral components are intended for use only with bone cement.

(PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON ANOTHER PAGE IF NEEDED) Concurrence of CDRH, Office of Device Evaluation

Prescription Use
(per 21 CFR 801.109)

Over-The-Counter Use

p colpo

(Division Sign-Off) Division of General Restorative Devices 510(k) Number_

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.