The S4 Screw System™ is indicated for fixation of small bone fragments, osteochondral fragments and cancellous fragments, appropriate for the device which may include the following: simple metaphyseal fractures; condylar fractures; osteochondritis dissecans; areas where accurate screw placement is vital; apical fragments (patellar); cancellous fragments (talus); osteochondral fragments (talar vault, femoral condyle); intra-articular fractures and osteochondral fixation and fractures.

Device Description

The S4 Screw System™ is collection of cannulated, headless screws having fenestrations on the head and within the thread pitch.

AI/ML Overview

The provided text describes a 510(k) premarket notification for the "S4 Screw System™". This document is an FDA submission for a medical device, which typically focuses on demonstrating substantial equivalence to a legally marketed predicate device rather than presenting a performance study with detailed acceptance criteria and standalone algorithm performance as one might find for an AI/ML device.

Based on the information provided, here's a breakdown regarding your request:

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

The document does not explicitly state "acceptance criteria" in the way one might for a diagnostic test with metrics like sensitivity, specificity, accuracy, etc. Instead, performance is demonstrated through mechanical testing against a recognized standard (ASTM F543) and comparison to predicate devices. The acceptance criteria are implicitly that the device's mechanical performance should be substantially equivalent to the predicate devices and meet the requirements of ASTM F543.

Performance Metric	Acceptance Criteria (Implicit)	Reported Device Performance
Torsion	Substantially equivalent to predicate devices per ASTM F543	Demonstrated substantial equivalence to predicate devices
Insertion	Substantially equivalent to predicate devices per ASTM F543	Demonstrated substantial equivalence to predicate devices
Pushout	Substantially equivalent to predicate devices per ASTM F543	Demonstrated substantial equivalence to predicate devices
Pyrogenicity	Meet specified pyrogenicity limit	Implants found to meet the specified pyrogenicity limit

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

The document mentions "mechanical testing of the worst case S4 Screw System™ and a predicate component." It does not specify the exact sample size (i.e., number of screws or components tested) for this mechanical testing. There is no information regarding data provenance in terms of country of origin or whether it was retrospective/prospective, as this applies more to clinical data which is not the primary focus of this type of submission for a bone fixation device.

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)

This question is not applicable to the S4 Screw System™ submission. This is a physical medical device (bone screw), and its performance is evaluated through mechanical testing, not a diagnostic or AI-driven assessment requiring expert interpretation to establish ground truth.

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

This question is not applicable. Adjudication methods are typically used in clinical studies, especially for diagnostic devices, to resolve disagreements among experts in establishing ground truth. Mechanical testing of a physical device does not involve this type of adjudication.

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

This question is not applicable. An MRMC study is relevant for diagnostic devices (often AI-assisted) where human readers interpret medical images or data. The S4 Screw System™ is a hardware device for bone fixation.

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

This question is not applicable. The S4 Screw System™ is a physical screw system, not an algorithm or AI.

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

For the mechanical testing, the "ground truth" is defined by the objective measurements obtained from the ASTM F543 standard tests (torsion, insertion, pushout) and the specified pyrogenicity limit for bacterial endotoxin testing. This is not "expert consensus", "pathology", or "outcomes data" in the typical sense; rather, it's adherence to established engineering and biological standards.

8. The sample size for the training set

This question is not applicable. There is no "training set" for a physical medical device like the S4 Screw System™. Training sets are relevant for AI/ML algorithms.

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

This question is not applicable for the same reason as #8.

Summary

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Image /page/0/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a circular seal with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" around the perimeter. Inside the circle is a stylized image of a human figure with three heads, representing the department's focus on health and human well-being.

Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002

September 7, 2017

Subchondral Solutions % Karen E. Warden, Ph.D. President Backroads Consulting Inc. PO Box 566 Chesterland, Ohio 44026

Re: K162171

Trade/Device Name: S4 Screw System™ Regulation Number: 21 CFR 888.3040 Regulation Name: Smooth Or Threaded Metallic Bone Fixation Fastener Regulatory Class: Class II Product Code: HWC Dated: August 7, 2017 Received: August 8, 2017

Dear Dr. Warden:

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. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to 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); medical device reporting (reporting of medical devicerelated adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in

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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.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to

http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.

You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.

Sincerely,

Katherine D. Kavlock -S

for Mark N. Melkerson Director Division of Orthopedic Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration

Indications for Use

Form Approved: OMB No. 0910-0120 Expiration Date: January 31, 2017 See PRA Statement on last page.

510(k) Number (if known) K162171

Device Name S4 Screw System™

Indications for Use (Describe)

Type of Use (Select one or both, as applicable)

∑ Prescription Use (Part 21 CFR 801 Subpart D)

_ Over-The-Counter Use (21 CFR 801 Subpart C)

PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON A SEPARATE PAGE IF NEEDED.

FOR FDA USE ONLY

Concurrence of Center for Devices and Radiological Health (CDRH) (Signature)

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510(k) Summary

Date:	7 August 2017
Sponsor:	Subchondral Solutions, Inc.147 Hillbrook DriveLos Gatos, CA 95032Office: 408.891.9604
Contact Person:	Sheryl McCoy, Chief Financial Officer and VP of Administration
510(k) Contact:	Karen E. Warden, PhDBackRoads Consulting Inc.PO Box 566Chesterland, OH 44026Office: 440.729.8457
Proposed Trade Name:	S4 Screw System™
Common Name:	Bone screw
Device Classification:	Class II
Regulation Name:	Smooth or threaded metallic bone fixation fastener
Regulation:	888.3040
Device Product Codes:	HWC
Device Description:	The S4 Screw System™ is collection of cannulated, headless screwshaving fenestrations on the head and within the thread pitch.
Indications for Use:	The S4 Screw System™ is indicated for fixation of small bone fragments,such as apical fragments, osteochondral fragments and cancellousfragments, appropriate for the size of the device which may include thefollowing: simple metaphyseal fractures; condylar fractures; osteochondritisdissecans; areas where accurate screw placement is vital; apical fragments(patellar rim, navicular); cancellous fragments (talus); osteochondralfragments (talar vault, femoral condyle); intra-articular fractures andosteochondral fixation and fractures.
Materials:	The S4 Screw System™ components are manufactured from titanium alloy(Ti-6Al-4V per ASTM F136).
Primary Predicate:	Acumed Cannulated Screw System (Acumed LLC. – K123890)
Additional Predicate:	Arthrex Compression FT Screws (Arthrex, Inc. - K132217)
Performance Data:	Mechanical testing of the worst case S4 Screw System™ and a predicatecomponent included torsion, insertion and pushout according to ASTMF543. The mechanical test results demonstrated that S4 Screw System™performance is substantially equivalent to the predicate devices.In addition, bacterial endotoxin testing was performed and the implantswere found to meet the specified pyrogenicity limit.
TechnologicalCharacteristics:	The S4 Screw System™ possesses similar technological characteristics asone or more of the predicate devices. These include:• performance (as described above),• basic design (cannulated, headless screws) and• implant materials (titanium alloy).Differences between the subject and predicate devices did not raise newquestions of safety and effectiveness. Therefore the fundamental scientifictechnology of the S4 Screw System™ is similar to previously cleareddevices.
Conclusion:	The S4 Screw System™ possesses the same intended use and similartechnological characteristics as the predicate devices. Therefore the S4Screw System™ is substantially equivalent for its intended use.

Regulation Number and Section

§ 888.3040 Smooth or threaded metallic bone fixation fastener.

(a)
Identification. A smooth or threaded metallic bone fixation fastener is a device intended to be implanted that consists of a stiff wire segment or rod made of alloys, such as cobalt-chromium-molybdenum and stainless steel, and that may be smooth on the outside, fully or partially threaded, straight or U-shaped; and may be either blunt pointed, sharp pointed, or have a formed, slotted head on the end. It may be used for fixation of bone fractures, for bone reconstructions, as a guide pin for insertion of other implants, or it may be implanted through the skin so that a pulling force (traction) may be applied to the skeletal system.(b)
Classification. Class II.