The Hoffmann® II Compact™ MRI components are intended to be used with the Half Pins or Transfixing Pins of the Hoffmann® External Fixation System and the components of the Hoffmann® II External Fixation System. It is intended to be used in the stabilization of open and/or unstable fractures and where soft tissue injury may preclude the use of other fracture treatments such as IM rodding, casting, and other means of internal fixation.

Device Description

This Special 510(k) submission is intended to address modifications to the predicate Hoffmann® II Compact "External Fixation Systems to include MRI conditional components for use in Magnetic Resonance Imaging (MRI) procedures under predetermined conditions

AI/ML Overview

The provided document is a 510(k) summary for the Hoffmann® II Compact™ MRI External Fixation System, which describes modifications to an existing device to include MRI conditional components. This type of regulatory filing focuses on demonstrating substantial equivalence to a predicate device, primarily through mechanical and MRI safety testing, rather than a clinical study evaluating diagnostic accuracy or reader performance with AI.

Therefore, many of the requested items (e.g., sample size for test/training sets, number of experts, adjudication methods, MRMC studies, standalone performance with AI, type of ground truth for diagnostic accuracy) are not applicable or cannot be extracted from this document as it pertains to a physical medical device (an external fixation system) and not a diagnostic AI algorithm.

However, I can extract information related to the acceptance criteria for the device's MRI compatibility and its demonstrated performance.

Acceptance Criteria and Device Performance for MRI Safety

Acceptance Criteria Category	Acceptance Criteria	Reported Device Performance
Mechanical Properties (Substantial Equivalence)	The modified components must demonstrate comparable mechanical properties to the predicate Hoffmann® II Compact™ External Fixation System.	"Mechanical testing demonstrated comparable mechanical properties to the predicate components." (The document does not detail specific numerical targets or results for mechanical properties, only that they were comparable).
MRI Safety (Conditional Use)	The modified components must be demonstrated to be safely usable in MRI diagnostic procedures under predetermined conditions. This typically involves assessing: 1. Magnetic Field Interaction (MR Compatibility): Evaluation of attractive or torsional forces in the strong static magnetic field. 2. RF-induced Heating: Assessment of temperature increase due to radiofrequency (RF) fields during MRI. 3. Artifacts: Evaluation of image distortion caused by the device during MRI.	"testing in a Magnetic Resonance Environment established that the components could be safely used in MRI diagnostic procedures under predetermined conditions." (The document states that the components were found to be MRI conditional, meaning they can be used safely under specific conditions. It does not provide the specific numerical results of the phantom or in-vitro tests conducted to define these conditions, such as the exact static field strength, SAR limits, or temperature rise observed, but implies these were successfully quantified and met relevant standards for MRI-conditional labeling).

Study Information (as applicable to a physical device modification for MRI compatibility):

Sample size used for the test set and the data provenance:
- Test Set Sample Size: Not applicable in the context of diagnostic performance testing for an AI. For MRI compatibility testing, the "sample size" would refer to the number of device components tested. The document does not specify the exact number of components or systems tested, but it implies comprehensive testing was performed ("Mechanical testing demonstrated..." and "testing in a Magnetic Resonance Environment established...").
- Data Provenance: The testing was presumably conducted in a laboratory setting by the manufacturer (Howmedica Osteonics Corp.) to assess the device's physical properties and MRI interaction. This would be considered "prospective" testing from the perspective of regulatory submission, as it was performed specifically for this modification and submission. "Country of origin" for data is not explicitly mentioned but typically relates to the testing facilities which, for a US-based company, would likely be in the US or affiliated international labs.
Number of experts used to establish the ground truth for the test set and the qualifications of those experts: Not applicable. This device is an external fixation system, not a diagnostic tool requiring expert interpretation of images or clinical outcomes for its primary function or MRI compatibility. The "ground truth" for MRI compatibility is established through standardized physical measurements in an MRI environment performed by qualified engineers and technicians.
Adjudication method for the test set: Not applicable. This concept pertains to resolving discrepancies in expert interpretations, which is not relevant for physical device testing concerning mechanical properties or MRI safety.
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 study type is for evaluating diagnostic AI, not an external fixation system.
If a standalone (i.e. algorithm only without human-in-the-loop performance) was done: Not applicable. This concept is for diagnostic AI, not an external fixation system.
The type of ground truth used:
- For mechanical properties, the ground truth is established through engineering standards and measurements (e.g., tensile strength, fatigue life) compared against the predicate device's known performance.
- For MRI safety, the ground truth is established through standardized phantom or in-vitro tests that measure force, torque, temperature rise, and artifact size in controlled MRI environments, adhering to standards like ASTM F2052, F2119, F2182 (or their equivalents at the time).
The sample size for the training set: Not applicable. This notion applies to machine learning algorithms, not to physical device testing for regulatory clearance based on substantial equivalence.
How the ground truth for the training set was established: Not applicable for the same reasons as above.

Summary

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NOV 2 2 2005

KOS3038 (pg 10f

Summary of Safety and Effectiveness Hoffmann® II Compact™ MRI External Fixation System

Proprietary Name:	Hoffmann® II Compact™ MRI External FixationSystem
Common Name:	External Fixation Frame Components
Classification Name and Reference	Single/multiple component metallic bone fixationappliances and accessories, 21 CFR §888.3030
Device Product Code:	87 KTT, 87 LXT & 87 JEC
For Information contact:	Vivian Kelly, Regulatory Affairs SpecialistHowmedica Osteonics Corp.325 Corporate DriveMahwah, NJ 07430Phone: (201) 831-5581Fax: (201) 831-6038
Date Summary Prepared:	October 25, 2005

Description:

Intended Use:

The subject and predicate devices are external fixation frames intended to provide stabilization of open and/or unstable fractures of the upper and lower extremities.

Indications for Use:

Substantial Equivalence:

The subject Hoffmann® II Compact™MRI components share the same intended use, and basic design concepts as that of the currently available Hoffmann® II Compact™ External Fixation System. Mechanical testing demonstrated comparable mechanical properties to the predicate components and testing in a Magnetic Resonance Environment established that the components could be safely used in MRI diagnostic procedures under predetermined conditions.

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DEPARTMENT OF HEALTH & HUMAN SERVICES

Image /page/1/Picture/1 description: The image shows a circular seal with the words "U.S. Public Health and Human Services" around the perimeter. Inside the circle is a stylized image of three human profiles facing right, with flowing lines connecting them. The image is in black and white and appears to be a logo or emblem.

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

NOV 2 2 2005

Vivian Kelly Regulatory Affairs Specialist Howmedica Osteonics Corp. 325 Corporate Drive Mahwah, New Jersey 07430

Re: K053038 Trade/Device Name: Hoffman® II Compact™ MRI External Fixation Systems Regulation Number: 21 CFR 888.3030 Regulation Name: Single/multiple component metallic bone fixation appliances and accessories Regulatory Class: II Product Code: KTT, JEC, LXT Dated: October 25, 2005 Received: October 27, 2005

Dear Ms. Kelly:

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 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 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 - Vivian Kelly

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 (240) 276-0120. 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/industry/support/index.html.

Sincerely yours.

Mark N. Melkerson

Acting 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

510(k) Number (if known): \५०५३०३८

Device Name: Hoffmann® II Compact™ MRI External Fixation Systems

Indications for Use:

Prescription Use X Over-The-Counter Use AND/OR (Part 21 CFR 801 Subpart D) (21 CFR 807 Subpart C) (PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE OF NEEDED)

Concurrence of CDRH, Office of Device Evaluation (ODE)

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signature

(Division Sign-Git) Division of General, Restorative. and Neurological Devices

510(k) Numberko 53038

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Regulation Number and Section

§ 888.3030 Single/multiple component metallic bone fixation appliances and accessories.

(a)
Identification. Single/multiple component metallic bone fixation appliances and accessories are devices intended to be implanted consisting of one or more metallic components and their metallic fasteners. The devices contain a plate, a nail/plate combination, or a blade/plate combination that are made of alloys, such as cobalt-chromium-molybdenum, stainless steel, and titanium, that are intended to be held in position with fasteners, such as screws and nails, or bolts, nuts, and washers. These devices are used for fixation of fractures of the proximal or distal end of long bones, such as intracapsular, intertrochanteric, intercervical, supracondylar, or condylar fractures of the femur; for fusion of a joint; or for surgical procedures that involve cutting a bone. The devices may be implanted or attached through the skin so that a pulling force (traction) may be applied to the skeletal system.(b)
Classification. Class II.