The Nextremity Solutions DuoHex™ CH Cannulated Hammertoe System is intended for small bone reconstruction limited to inter-phalangeal repair and fusion of the lesser toes.

Device Description

The DuoHex™ CH Cannulated Hammertoe System consists of a two-part cannulated bone screw implant construct. The screw implants are provided in various sizes. The proximal screw implant diameters range from 2.75mm to 4.2mm. The middle screw implant diameters range from 2.75mm to 5.0mm in increments of 0.75mm. The proximal and distal screw implants are manufactured from Ti-6Al-4V ELI conforming to ASTM F136. The system offers an optional fixation method using a Kirschner wire (K-wire) in conjunction with the screw implants for additional fixation and temporary stabilization. The K-Wire is intended to be removed at the discretion of the physician upon joint fusion. The k-wires provided are manufactured from 316 Stainless Steel conforming to ASTM F138. The system includes the necessary surgical site preparation and insertion instruments.

AI/ML Overview

This document describes a medical device, the DuoHex™ CH Cannulated Hammertoe System, and its clearance by the FDA based on substantial equivalence to predicate devices. It does not present clinical performance data or studies against specific acceptance criteria for AI/ML-driven medical devices.

Therefore, I cannot provide the details requested in your prompt for acceptance criteria and study data for an AI/ML device. The provided text is a 510(k) summary for a non-AI/ML medical device (bone screw system) and primarily relies on mechanical testing and comparison to existing products for substantial equivalence.

Here's a breakdown of why I cannot fulfill your request based on the provided text:

The document explicitly states: "Clinical testing was not necessary to demonstrate substantial equivalence of the DuoHex™ CH Cannulated Hammertoe System to the predicate device." This means no clinical study was performed to "prove the device meets the acceptance criteria" in the way you've described for an AI/ML system.
The device is a "Bone Screw System" for hammertoe correction, a mechanical implant, not an AI/ML diagnostic or therapeutic guidance tool.
The "Non-Clinical Testing" section describes mechanical and material tests (axial pull-out strength, torque to failure, static/dynamic 3-point bend tests) and endotoxin testing, not performance metrics like sensitivity, specificity, or AUC as would be relevant for an AI/ML system.

To answer your request, if this were an AI/ML device, and assuming a hypothetical scenario where the document would contain the necessary information, a typical response would look like this (but again, this is NOT supported by the provided text):

Hypothetical Acceptance Criteria and Study for an AI/ML-Driven Hummer Toe Diagnostic System (Illustrative - NOT based on the provided document)

Let's imagine, for the sake of demonstrating the structure, that the DuoHex™ CH system included an AI component that diagnosed hammertoe severity from medical images.

1. Table of Acceptance Criteria and Reported Device Performance

Performance Metric	Acceptance Criteria (e.g., Minimum Threshold)	Reported Device Performance
Primary Endpoint
Sensitivity	≥ 90%	92.5%
Specificity	≥ 85%	87.2%
Secondary Endpoints
AUC	≥ 0.90	0.93
PPV	≥ 70%	75.1%
NPV	≥ 95%	96.8%

Note: The actual document does not contain any such performance metrics as it's for a mechanical device.

2. Sample Size and Data Provenance

Test Set Sample Size: 500 patient cases (e.g., foot X-rays)
Data Provenance: Retrospective data collected from multiple clinical sites across the United States and Europe (e.g., Germany, UK).

Note: The actual document does not mention any test set or data provenance in this context.

3. Number and Qualifications of Experts for Ground Truth

Number of Experts: 3 independent orthopedic radiologists.
Qualifications: Each radiologist had at least 15 years of experience specializing in musculoskeletal imaging, with a focus on foot and ankle pathologies. All were board-certified in their respective countries.

Note: The actual document does not mention any experts for ground truth establishment.

4. Adjudication Method for Test Set

Adjudication Method: 2+1 Adjudication. If at least two out of three experts agreed on a diagnosis (e.g., severity of hammertoe), that was considered the provisional ground truth. In cases of disagreement (e.g., 1-1-1 split), a fourth senior orthopedic surgeon (with 25+ years experience) acted as a tie-breaker/final adjudicator.

Note: The actual document does not mention any adjudication method.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

Was an MRMC study done? Yes.
Effect Size of Human Reader Improvement:
- Without AI assistance: Average diagnostic accuracy of human readers was 78%.
- With AI assistance (AI-assisted read): Average diagnostic accuracy of human readers improved to 89%.
- Effect Size: The AI assistance led to an average increase of 11 percentage points in diagnostic accuracy for human readers (p < 0.001, 95% CI: [9.5%, 12.5%]). This represents a significant improvement in reader performance.

Note: The actual document does not mention any MRMC study or AI assistance.

6. Standalone Algorithm Performance

Was standalone performance done? Yes.
Standalone Performance Metrics:
- Sensitivity: 91.8%
- Specificity: 86.5%
- AUC: 0.92

Note: The actual document does not mention any standalone algorithm performance.

7. Type of Ground Truth Used

Type of Ground Truth: Expert consensus based on clinical examination, high-resolution MRI scans, and follow-up surgical pathology reports when available for definitive confirmation of hammertoe severity and presence.

Note: The actual document does not mention any ground truth type in this context.

8. Sample Size for the Training Set

Training Set Sample Size: 10,000 anonymized patient cases (X-rays, medical reports).

Note: The actual document does not mention any training set.

9. How Ground Truth for Training Set Was Established

Ground Truth for Training Set: Established by an internal team of 10 experienced orthopedic specialists (orthopedic surgeons and radiologists) who labeled the image data and associated clinical information. A subset of these labels (10%) was independently reviewed by a senior specialist for quality assurance. Data was semi-automatically labeled using a pre-trained model and then manually refined and verified by the experts.

Note: The actual document does not mention ground truth for a training set.

In conclusion, the provided FDA clearance letter and 510(k) summary are for a mechanical bone screw system and do not contain any information related to AI/ML device performance, acceptance criteria, or clinical studies of the type you are asking about.

Summary

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June 26, 2020

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Nextremity Solutions, Inc. Elise Fox Quality Engineer 210 North Buffalo Street Warsaw, Indiana 46580

Re: K200840

Trade/Device Name: DuoHex CH Cannulated Hammertoe System Regulation Number: 21 CFR 888.3040 Regulation Name: Smooth Or Threaded Metallic Bone Fixation Fastener Regulatory Class: Class II Product Code: HWC, NDL Dated: March 27, 2020 Received: March 31, 2020

Dear Elise Fox:

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. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. 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

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801); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

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 https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.

For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely,

Shumaya Ali, MPH Assistant Director DHT6C: Division of Restorative, Repair and Trauma Devices OHT6: Office of Orthopedic Devices Office of Product Evaluation and Quality Center for Devices and Radiological Health

Enclosure

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Indications for Use

510(k) Number (if known)

K200840

Device Name DuoHex™ CH Cannulated Hammertoe System

Indications for Use (Describe)

The Nextremity Solutions DuoHex™ CH Cannulated Hammertoe System is intended for small bone reconstruction limited to inter-phalangeal repair and fusion of the lesser toes.

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

ü Prescription Use (Part 21 CFR 801 Subpart D)
□ Over-The-Counter Use (21 CFR 801 Subpart C)

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510(k) Summary
Prepared:	June 24th, 2020
Submitter:	Nextremity Solutions, Inc.210 North Buffalo StreetWarsaw, IN 46580
Contact:	Elise FoxQuality and Regulatory Specialistelise.fox@nextremity.comPhone: 574-376-2062FAX: 574-966-1396
Proprietary Name:	DuoHexTM CH Cannulated Hammertoe System
Common Name:	Bone Screw System
Classification:	21 CFR § 888.3040 Smooth or threaded metallic bone fixation fastener;Class II
Product Code:	HWC-primary product code, NDL
Substantially

Equivalent Devices:

. Nextremity Solutions, Nextra Ti Hammertoe Correction System, K122031-Primary Predicate
Nextremity Solutions, Nextra Hammertoe Correction System (Cleared as FlexFusion . Fixation System), K110445- Additional Predicate
Wright Medical Technology, Inc PHALINX Hammertoe System, K150252- Additional . Predicate

Device Description:

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ASTM F138. The system includes the necessary surgical site preparation and insertion instruments.

Intended Use / Indications:

The Nextremity Solutions DuoHex™ CH Cannulated Hammertoe System is intended for small bone reconstruction limited to inter-phalangeal repair and fusion of the lesser toes.

Summary of Technologies/Substantial Equivalence:

The DuoHex™ CH Cannulated Hammertoe System is substantially equivalent to the predicate devices regarding the intended use and indications, material, design, sizes, and mechanical properties. Differences between the subject device system and the predicate device systems do not raise new types of safety and effectiveness questions.

Non-Clinical Testing:

Endotoxin testing was performed using the Limulus Amebocyte Lysate (LAL) method according to AAMI ST72, USP 161 and USP 85. Results met the Endotoxin limit of <20 EU per device. To evaluate the strength of the DuoHex™ CH Cannulated Hammertoe System and components, axial pull-out strength and torque to failure were performed on worst case screws according to ASTM F543-17. Static 3-point bend tests and dynamic 3-point bend tests were performed on the worst case implant construct according to ASTM F2193-18a. These tests confirmed that the strength of the DuoHex 114 CH Cannulated Hammertoe System is substantially equivalent to predicate devices with similar indications and is adequate for its intended use.

Clinical Testing:

Clinical testing was not necessary to demonstrate substantial equivalence of the DuoHex™ CH Cannulated Hammertoe System to the predicate device.

Conclusions/Substantial Equivalence:

Differences between the subject device system and the predicate device systems do not raise new types of safety and effectiveness questions. The DuoHex™ CH Cannulated Hammertoe System is substantially equivalent to the predicate devices in regard to its intended use, material, design, sizes, and mechanical properties.

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.