DURATION STABILIZED UHMWPE ACETABULAR COMPONENTS by HOWMEDICA CORP.

The Exeter All Plastic Acetabular Component (previously cleared in K936132) is intended to be used for primary and secondary reconstruction of the bearing surface of the acetabulum as a result of painful and/or severly disabled hip joints due to osteoarthritis, rheumatoid arthritis, post-traumatic arthritis or revision of a failed acetabular component.

The Howmedica® Bipolar Prosthesis, Centrax® (previously cleared in K855231) is intended to be used in conjunction with a femoral stem component for the reconstruction of a femoral head damaged by fresh fracture, non-union, aseptic necrosis of the head and neck, or by osteoarthritis or post-traumatic arthritis.

Device Description

This submission describes additional UHMWPE acetabular components that can be sterilized by the Duration® Stabilized process previously cleared in submission K934060, as an alternate to standard air irradiated gamma sterilization. The additional components are the Exeter All Plastic Acetabular Component (K936132) and the Howmedica® Bipolar Prosthesis, Centrax® (K855231). Corresponding wear claims, previously cleared in submission K 963612 and listed below, are also applicable to these additional components.

AI/ML Overview

The provided document describes wear claims for Duration® Stabilized UHMWPE Acetabular Components through in vitro testing. It does not detail specific acceptance criteria in a quantitative manner (e.g., "device must achieve X performance in Y metric"). Instead, the performance is presented as a reduction in volumetric wear compared to a conventionally sterilized equivalent. This suggests the acceptance criterion was "demonstrate a reduction in volumetric wear" and the studies performed to meet this criterion successfully showed such a reduction.

Here's an analysis of the provided information:

1. Table of Acceptance Criteria and Reported Device Performance

Acceptance Criterion (Implied)	Reported Device Performance
Demonstrates a reduction in volumetric wear compared to conventionally gamma sterilized UHMWPE in a multiaxial hip joint simulator.	36% reduction in volumetric wear for Duration® Stabilized UHMWPE (System 12®, P4, 32mm ID, 6.1mm bearing thickness, 6 months aged in oxygen) vs. conventionally gamma sterilized equivalent (6 months aged in oxygen). (Tested over 10 million cycles)
	40% reduction in volumetric wear for Duration® Stabilized UHMWPE (generic hemispherical cup, 32 mm ID, 8.4 mm bearing thickness) vs. conventionally gamma sterilized equivalent. (Tested over 5 million cycles)
	40% reduction in volumetric wear for Duration® Stabilized UHMWPE (System 12® Neutral Acetabular Insert, P4, 32mm ID, 6.1mm bearing thickness) vs. conventionally gamma sterilized equivalent. (Tested over 5 million cycles)
Demonstrates a reduction in volumetric wear compared to conventionally gamma sterilized UHMWPE after accelerated aging.	27% reduction in volumetric wear for Duration® Stabilized UHMWPE (generic hemispherical cup, 32mm ID, 8.4mm bearing thickness, 11 days heating in air to simulate 5 years "aging") vs. conventionally gamma sterilized equivalent (with same aging). (Tested over 10 million cycles)

Note on Acceptance Criteria: The document presents the results as statements of fact rather than explicit "criteria." The FDA's 510(k) clearance process relies on demonstrating "substantial equivalence" to a predicate device. For material claims like reduced wear, demonstrating a quantitatively superior or equivalent performance to a legally marketed predicate (or baseline, in this case, conventionally sterilized UHMWPE) serves as the basis for clearance. The "acceptance" is implicitly tied to these demonstrated reductions.

2. Sample Size Used for the Test Set and Data Provenance

Sample Size: The document does not explicitly state a "sample size" in terms of number of individual components tested in each condition. It refers to single tests or sets of tests (e.g., "System 12®, size P4, neutral acetabular inserts," "a hemispherical cup of generic design"). Typically, such in vitro wear testing involves a small number of samples (often n=3 or n=5) for each condition, but this detail is not provided.
Data Provenance: The data is generated from in vitro laboratory testing using multiaxial hip joint simulators. The studies were conducted by Howmedica Inc. and an "independent laboratory" for one of the tests. The document explicitly states: "The results of in vitro tests have not been shown to correlate with clinical wear mechanisms."

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

Not applicable. This is an in vitro mechanical wear test of a medical device, not a diagnostic or clinical study requiring human experts for ground truth establishment. The "ground truth" here is the measured volumetric wear in a controlled laboratory environment.

4. Adjudication Method for the Test Set

Not applicable. As noted above, this is an in vitro mechanical test, so there is no expert adjudication process. The measurements of volumetric wear are objective and quantifiable by laboratory equipment.

5. 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

Not applicable. This is not an AI/human-in-the-loop study. It's an in vitro material performance study.

6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done

Not applicable. This is explicitly an in vitro mechanical wear test of a physical medical device (UHMWPE acetabular components). It is not an algorithm, AI, or software device.

7. The Type of Ground Truth Used

The ground truth used is objective, quantitatively measured volumetric wear determined by laboratory testing in a hip joint simulator. This is a direct physical measurement, not based on expert consensus, pathology, or outcomes data, as explicitly warned by the statement: "The results of in vitro tests have not been shown to correlate with clinical wear mechanisms."

8. The Sample Size for the Training Set

Not applicable. This is an in vitro performance study for a physical device, not an AI or machine learning model. Therefore, there is no "training set."

9. How the Ground Truth for the Training Set was Established

Not applicable, as there is no training set.

Summary

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510(k) Summary

K972792

Proprietary Name: Duration® Stabilized UHMWPE Acetabular Components

Common Name: UHMWPE Acetabular Components

21 CFR 888.3358 Classification Name and Reference:

Proposed Requlatory Class: Class II Device Product Code: JDI

For information contact: Frank Maas Manager, Regulatory Affairs Howmedica Inc. 359 Veterans Boulevard Rutherford, NJ 07070 Telephone: (201) 507-7875 Fax: (201) 507-6870 Date Summary Prepared: 7-25-97

Howmedica's Duration® Stabilized UHMWPE, System 12®, size P4, neutral acetabular inserts, with an inner diameter of 32mm, a bearing thickness of 6.1 mm and aged for 6 months in an oxygen environment, showed a 36% reduction in volumetric wear versus the same cup conventionally gamma sterilized and aged for 6 months in an oxygen environment. Testing was performed in a multiaxial hip joint simulator for over 10 million cycles, using a 32mm CoCr Head articulating counterface and bovine calf serum as a lubricant. The results of in vitro tests have not been shown to correlate with clinical wear mechanisms.

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Howmedica's Duration® Stabilized UHMWPE, a hemispherical cup of generic design for hip simulator testing, with an inner diameter of 32 mm, and a bearing thickness of 8.4 mm, showed a 40% reduction in volumetric wear versus the same cup conventionally gamma sterilized. Testing was performed in a multiaxial hip joint wear simulator for over 5 million cycles, using a 32 mm diameter CoCr Head articulating counterface and tow calcium" containing bovine calf serum as a lubricant. The results of in vitro tests have not been shown to correlate with clinical wear mechanisms.

Howmedica's Duration® Stabilized UHMWPE, System 12® Neutral Acetabular Insert, size P4. with an inner diameter of 32mm, and a bearing thickness of 6.1 mm, showed a 40% reduction in volumetric wear versus the same cup conventionally gamma sterilized. Testing was performed in a hip joint wear simulator for over 5 million cycles, using a 32 mm CoCr Head articulating counterface and high calcium" containing bovine calf serum as a lubricant. The results of these in vitro tests have not been shown to correlate with clinical wear mechanisms or in vitro third body wear mechanisms involving fragments of bone cement, UHMWPE , metal, ceramic, etc.

In an independent laboratory test on Howmedica's Duration® Stabilized UHMWPE, a hemispherical cup of generic design for hip simulator testing, with an inner diameter of 32 mm, a bearing thickness of 8.4 mm, and having undergone 11 days of heating in air to simulate 5 years "aging", showed a 27% reduction in volumetric wear versus the same cup conventionally gamma sterilized, having undergone 11 days of heating in air to simulate 5 years "aging". Testing was performed in a multiaxial hip joint wear simulator over 10 million cycles, using a 32 mm CoCr Head articulating counterface and bovine calf serum as a lubricant. The results of in vitro tests have not been shown to correlate with clinical wear mechanisms.

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Image /page/2/Picture/2 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a circular border with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES USA" arranged around the perimeter. Inside the circle is a stylized symbol that resembles a bird or a human profile, composed of three curved lines. The logo is presented in black and white.

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

Mr. Frank Maas .Manager, Requlatory Affairs Howmedica, Inc. Pfizer Hospital Products Group 359 Veterans Boulevard Rutherford, New Jersey 07070

OCT 1 6 1997

Re: K972792 Duration Stabilized UHMWPE Exeter All Trade Name: Plastic Acetabular Component and Centrex® Bipolar Component Regulatory Class: II Product Codes: JDI and KWY Dated: July 25, 1997 Received: July 28, 1997

Dear Mr. Maas:

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. ਜੋ substantially equivalent determination assumes compliance with the current Good Manufacturing Practice requirement, as set forth in the Quality System Regulation (QS) for Medical General regulation (21 CFR Part 820) and that, Devices: 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:

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Page 2 - Mr. Frank Maas

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 enrough on or or on control provisions, or other Federal laws or regulations.

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 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 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.qov/cdrh/dsmamain.html".

Sincerely yours,

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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ications for Use

510(k) Number (if known):

Device Name: Duration® Stabilized UHMWPE Acetabular Components

Indications for Use:

SEE NEXT PAGE FOR DURATION® WEAR CLAIMS

(PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Office of Device Evaluation (ODE)

Prescription Use	X	OR	Over-The-Counter Use
(Per 21 CFR 801.109)

(Division Sign-Off)

D - General Restorative Devices

510(k) K972792 (Optional Format 1-2-96)

Regulation Number and Section

§ 888.3350 Hip joint metal/polymer semi-constrained cemented prosthesis.

(a)
Identification. A hip joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace a hip 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 an acetabular resurfacing component made of ultra-high molecular weight polyethylene and is limited to those prostheses intended for use with bone cement (§ 888.3027).(b)
Classification. Class II.