patient conditions of noninflammatory degenerative joint disease (NIDJD); e.g., avascular . necrosis, osteoarthritis and inflammatory joint disease (IJD), e.g., rheumatoid arthritis.
those patients with failed previous surgery where pain, deformity, or dysfunction persists. .
revision of a previously failed hip arthroplasty. .
patients who require a total hip replacement. .

Device Description

The Alloclassic Zweymüller SL Offset Femoral Stem is very similar to the previously cleared Alloclassic Zweymüller SL Femoral Stem in that it is:

a conically shaped straight stem with a rectangular cross section (for rotational stability). 1.
the same design, distal to the line of resection. 2.
manufactured from wrought Ti-Al-Nb titanium alloy (Protasul-100™, ISO 5832-11/ASTM 3. F1295).
grit blasted, below the neck, to enhance the bone-prosthesis interface. 4.
In contrast, this stem provides an additional 6.25mm of offset (per size) and has a CCD/neck angle of 121° (vs. 131° for SL stem). Overall, this new design provides a higher offset sometimes needed for:
1. correcting insufficient soft tissue balancing,
1. restoration of leg length, and
sufficient joint stability following total hip arthroplasty. 3.

AI/ML Overview

The provided text is a 510(k) summary for a medical device called the "Alloclassic™ Zweymüller™ SL Offset Femoral Stem." This type of document is a submission to the FDA to demonstrate substantial equivalence to an existing legally marketed device. It typically focuses on design, materials, and intended use comparison rather than clinical study data proving performance against specific acceptance criteria in the way a diagnostic AI device would.

Therefore, many of the requested points, especially those related to clinical studies, diagnostic performance, ground truth, and expert evaluation, are not applicable to this type of regulatory submission for a prosthetic hip stem. The document does not describe a study to prove the device meets acceptance criteria in a quantitative sense of diagnostic accuracy or clinical outcomes assessed by a clinical trial. Instead, it argues for substantial equivalence based on design and material similarities to a predicate device.

Here's a breakdown based on the available information:

1. A table of acceptance criteria and the reported device performance

Acceptance Criteria: The document does not explicitly state quantitative acceptance criteria in terms of performance metrics (like sensitivity, specificity, accuracy) that a diagnostic device would have. The "acceptance criteria" for a 510(k) submission for a hip stem are typically related to demonstrating substantial equivalence in terms of:
- Same indications for use.
- Similar design principles (shape, material, mechanism of action).
- Similar materials of construction.
- Similar manufacturing processes.
- No new questions of safety or effectiveness.
Reported Device Performance: The document does not report performance data from a clinical study for the new device itself. Instead, it highlights design differences and their intended benefits:
- Provides an additional 6.25mm of offset (per size).
- Has a CCD/neck angle of 121° (vs. 131° for the SL stem).
- These design changes are intended for:
  - Correcting insufficient soft tissue balancing.
  - Restoration of leg length.
  - Sufficient joint stability following total hip arthroplasty.
- The document implies that the performance (safety and effectiveness) is substantially equivalent to the predicate device due to shared fundamental characteristics.

2. Sample size used for the test set and the data provenance (e.g., country of origin of the data, retrospective or prospective)

Not Applicable. This document describes a 510(k) submission based on design and material comparison, not a clinical study with a test set of patient data.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g., radiologist with 10 years of experience)

Not Applicable. No test set or ground truth determination by experts is described in this document.

4. Adjudication method (e.g., 2+1, 3+1, none) for the test set

Not Applicable. No test set or adjudication process is described.

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 a hardware orthopedic implant, not an AI-assisted diagnostic device.

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

Not Applicable. This is a hardware orthopedic implant, not an algorithm.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)

Not Applicable. No ground truth is described as there is no diagnostic study. The "ground truth" for the substantial equivalence argument is the established safety and effectiveness of the predicate device (K030373), which is assumed to be safe and effective based on its own prior regulatory clearance.

8. The sample size for the training set

Not Applicable. There is no "training set" in the context of an AI/diagnostic device. For a hip stem, this would refer to design validation and verification activities (e.g., mechanical testing, fatigue testing) often done on prototypes, but these are not clinical "training sets."

9. How the ground truth for the training set was established

Not Applicable. As above, no training set or ground truth in the AI/diagnostic sense is applicable here. The "ground truth" for design validation is typically engineering specifications and performance standards established through biomechanical testing, material science, and established surgical principles.

Summary

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DEC 1 7 2003

K033664

PAGE 1 of 2

510(k) SUMMARY

In accordance with the Food and Drug Administration Rule to implement provisions of the Safe Medical Devices Act of 1990 and in conformance with 21 CFR 807, this is to serve as a Summary of Safety and Effectiveness for the Centerpulse Orthopedics Ltd. Alloclassic™ Zweymüller™ SL Offset Femoral Stem.

Manufacturer:	Centerpulse Orthopedics Ltd.Altgasse 44CH-6340 Baar, Switzerland
US Distributor:	Centerpulse Orthopedics Inc.9900 Spectrum DriveAustin, Texas 78717(512) 432-9900
Date:	November 20, 2003
Contact Person:	Jean AsquithRegulatory Affairs Specialist(512) 432-9900 X8212
Classification Name:	21 CFR Part 888.3353 - Hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis
Common/Usual Name:	Femoral Hip Stem
Trade/Proprietary Name:	AlloclassicTM ZweymüllerTM SL Offset Femoral Stem

PRODUCT DESCRIPTION

The Alloclassic Zweymüller SL Offset Femoral Stem is very similar to the previously cleared Alloclassic Zweymüller SL Femoral Stem in that it is:

a conically shaped straight stem with a rectangular cross section (for rotational stability). 1.
the same design, distal to the line of resection. 2.
manufactured from wrought Ti-Al-Nb titanium alloy (Protasul-100™, ISO 5832-11/ASTM 3. F1295).
grit blasted, below the neck, to enhance the bone-prosthesis interface. 4.

In contrast, this stem provides an additional 6.25mm of offset (per size) and has a CCD/neck angle of 121° (vs. 131° for SL stem). Overall, this new design provides a higher offset sometimes needed for:

1. correcting insufficient soft tissue balancing,
1. restoration of leg length, and
sufficient joint stability following total hip arthroplasty. 3.

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133664

Page 2 of 2

SPECIFIC DIAGNOSTIC INDICATIONS

There have been no changes in the diagnostic indications for use as compared to the unmodified device.

The Alloclassic Zweymüller SL Offset Femoral Stem is intended for non-cemented use to replace the anatomy of the femur in cases of total hip replacement. It is intended to be used with the anatomy of the formal and metallic or ceramic femoral heads possessing a 12/14 taper.

The indications for use of the Alloclassic Zweymüller SL Offset Femoral Stem are for treatment of the following:

patient conditions of noninflammatory degenerative joint disease (NIDJD), e.g., avascular ♥ necrosis, osteoarthritis, and inflammatory joint disease (IJD), e.g., rheumatoid arthritis.
those patients with failed previous surgery where pain, deformity, or dysfunction persists. .
revision of a previously failed hip arthroplasty. .
patients who require a total hip replacement. .

SUBSTANTIAL EQUIVALENCE

Therefore, based on the information provided, Centerpulse Orthopedics believes the Alloclassic Therefore, SL Offset Fernoral Stem is substantially equivalent to the previously cleared, Zweymäller SL Femoral Stem (ref. K030373 as Exhibit 3) as it has the same indications for use, basic design, sizes, material, sterilization method, and method of manufacture.

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Image /page/2/Picture/2 description: The image shows the seal of the U.S. Department of Health and Human Services. The seal is circular and contains the department's name around the perimeter. In the center is an abstract symbol that resembles an eagle or a stylized human figure. The image is in black and white.

DEC 17 2003

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

Ms. Jean Asquith Regulatory Affairs Specialist Centerpulse Orthopedics Inc. 9900 Spectrum Drive Austin, Texas 78717

Re: K033664 R05500+
Trade/Device Name: Alloclassic" Zweymüller"" SL Offset Stem Regulation Number: 21 CFR 888.3353 Regulation Name: Hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis Regulatory Class: II Product Codes: LZO, JDI, KWY, KWL Dated: November 20, 2003 Received: November 21, 2003

Dear Ms. Asquith:

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 your 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 Codc 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 any 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 (QS) 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 - Ms. Jean Asquith

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), please contact the Office of Compliance at (301) 594-4659. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). You may obtain other general information on your responsibilities under the Act 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,

b. Mark N. Millburn

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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Page 1 of 1

510(k) Number (if known):

Device Name: Alloclassic SL Offset Femoral Stem

Indications for Use:

The Alloclassic SL Offset Femoral Stem is intended for prosthetic replacement without bone cement in treatment of the following:

patient conditions of noninflammatory degenerative joint disease (NIDJD); e.g., avascular . necrosis, osteoarthritis and inflammatory joint disease (IJD), e.g., rheumatoid arthritis.
those patients with failed previous surgery where pain, deformity, or dysfunction persists. .
revision of a previously failed hip arthroplasty. .
patients who require a total hip replacement. .

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

Concurrence of CDRH, Office of Device Evaluation (ODE)

Prescription Use √

Over-The-Counter Use

Mark n Millken

(Optional Format 1-2-96)

Division Sign-Off
Division of General, Restorative
and Neurological Devices

Number K033

Regulation Number and Section

§ 888.3353 Hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis.

(a)
Identification. A hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis is a device intended to be implanted to replace a hip joint. This device limits translation and rotation in one or more planes via the geometry of its articulating surfaces. It has no linkage across-the-joint. The two-part femoral component consists of a femoral stem made of alloys to be fixed in the intramedullary canal of the femur by impaction with or without use of bone cement. The proximal end of the femoral stem is tapered with a surface that ensures positive locking with the spherical ceramic (aluminium oxide, A12 03 ) head of the femoral component. The acetabular component is made of ultra-high molecular weight polyethylene or ultra-high molecular weight polyethylene reinforced with nonporous metal alloys, and used with or without bone cement.(b)
Classification. Class II.