Triathlon AS-1 by Conformis Inc.

The Triathlon AS-1 patient specific cutting guides are disposable, single-use surgical instruments intended to assist orthopedic surgeons in the positioning of femoral and tibial total knee arthroplasty components intraoperatively, provided that anatomic landmarks necessary for alignment and positioning of the implant are identifiable on patient imaging scans. They are intended for use with the Cruciate Retaining (CR), Condylar Stabilizing (CS), Posterior Stabilized (PS) and Tritanium® components of the Triathlon® Total Knee System and the Total Stabilizer (TS) and Posterior Stabilized Rotation (PSR) Triathlon® tibial inserts.

Device Description

The subject device, Triathlon AS-1, is a new Conformis Inc. device offering. The Triathlon AS-1 is comprised of patient matched single-use disposable cutting guides (also referred to as instruments or jigs) with corresponding surgical documentation which includes the Instructions for Use, Surgical Protocol and Surgical Plan. The single-use patient-matched instruments (including documentation) are similar to those of the legally marketed predicate device Knee Replacement Systems by Conformis Inc. (predicate devices K180906, K201023).

The subject device, Triathlon AS-1, does not include an implant or reusable instrumentation associated with knee replacement systems. The subject device, however, is designed to be compatible with selected legally marketed Triathlon Total Knee implants and reusable instrumentation from Stryker Orthopaedics. While no implant is part of this subject device, the subject device utilizes software to determine the size and position of the compatible implant for an individual patient and then design the subject device around the patient's anatomy to prepare for the identified implant.

For the subject device, the predicate Conformis design software, surgical plan, and single-use cutting guides (instrumentation) are being modified to accurately size, position, and prepare the bone for off-the-shelf Triathlon femoral and tibial implants. Using patient imaging (CT scans), a Triathlon Total Knee implant set is sized and positioned to best meet the unique anatomic requirements of the specific patient. The Triathlon AS-1 planning process allows for efficient 3D planning, providing optimized fit of an off-the-shelf Triathlon implant and providing the design of the patient-matched, single-use guides to prepare for the planned implant in the planned position.

Jigs are designed to fit the contours of the patient's femoral and tibial anatomies and to facilitate a simpler surgical technique. The design of the instrumentation will be modified as needed to be compatible with the Stryker Orthopaedics Triathlon manual surgical instrumentation.

Each set of instruments is designed for single use, specifically for one patient. The disposable single-use instrument set is manufactured from biocompatible nylon material and supplied sterile.

AI/ML Overview

Note: The provided text is a 510(k) summary for a medical device (surgical cutting guides). It primarily focuses on demonstrating substantial equivalence to predicate devices and does not contain detailed information about a study proving the device meets specific acceptance criteria in the manner of an AI/ML algorithm evaluation (e.g., performance metrics like sensitivity, specificity, or AUC).

Therefore, I cannot fully address all aspects of your request, particularly those related to the performance of an AI/ML device, such as sample sizes for test/training sets, ground truth establishment methods, expert adjudication, or MRMC studies. The document describes a traditional medical device (patient-specific cutting guides) whose "performance" would relate to its physical properties, manufacturing quality, and usability.

Based on the provided text, I will address what information is available and indicate where it is not provided.

Acceptance Criteria and Study Proving Device Meets Acceptance Criteria

Overview: The provided document is a 510(k) summary for the Triathlon AS-1 patient-specific cutting guides. The "acceptance criteria" in this context are primarily related to demonstrating substantial equivalence to legally marketed predicate devices, ensuring the device is safe and effective, and performs as well as the predicate. The "study" described is a series of non-clinical tests and evaluations rather than a traditional clinical trial or AI/ML performance study.

1. Table of Acceptance Criteria and Reported Device Performance

Given the nature of the device (surgical cutting guides) and the 510(k) submission, the "acceptance criteria" are not presented as quantitative performance metrics for an AI/ML model. Instead, the focus is on functional equivalence and safety.

Acceptance Criteria (Implied by 510(k) Process for this device)	Reported Device Performance / Means of Proof
Functional Equivalence to Predicate Devices	The device (Triathlon AS-1) performs the same function and has the same intended use as the iJigs in the predicate devices (Conformis Total Knee Replacement Systems: K180906, K201023). Modifications to single-use patient-matched instruments do not raise new safety/effectiveness issues. The CAD design processes, material, manufacturing process (selective laser sintering), packaging, and sterilization methods are the same as predicate devices.
Safety and Effectiveness	Non-clinical data provided supports that the subject device is safe, effective, and performs as well as the predicate device. No new issues of safety or effectiveness were raised.
Compatibility with Stryker® Total Knee System	The device is designed to be compatible with selected legally marketed Triathlon Total Knee implants and reusable instrumentation from Stryker Orthopaedics. Software is used to determine the size and position of the compatible implant and design the device around the patient's anatomy. Instrumentation design is modified to be compatible with Stryker Orthopaedics Triathlon manual surgical instrumentation.
Biocompatibility	The disposable single-use instrument set is manufactured from biocompatible nylon material.
Sterility	The disposable single-use instrument set is supplied sterile.
Usability/Surgical Assistance	Intended to assist orthopedic surgeons in positioning femoral and tibial total knee arthroplasty components intraoperatively, provided anatomic landmarks are identifiable on patient imaging scans. Jigs are designed to fit the contours of the patient's femoral and tibial anatomies and to facilitate a simpler surgical technique.
Specific Testing Conducted	Cadaver testing (surgeon evaluation and usability), Implant sizing and positioning testing, Software verification and validation.

2. Sample size used for the test set and the data provenance

Test Set Sample Size: Not explicitly stated in the document. The testing involved "Cadaver testing" and "Implant sizing and positioning testing," but the number of cadavers or patient cases used for these tests is not provided.
Data Provenance: Not specified (e.g., country of origin, retrospective/prospective). The data appears to be from non-clinical testing (cadavers, software validation).

3. Number of experts used to establish the ground truth for the test set and qualifications of those experts

Number of Experts: Not specified. "Surgeon evaluation" is mentioned for cadaver testing, implying expert involvement, but the number or specific qualifications (e.g., "radiologist with 10 years of experience") are not detailed. Given the device, these would likely be orthopedic surgeons.

4. Adjudication method for the test set

Adjudication Method: Not specified.

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

MRMC Study: No, an MRMC study was not stated to be done. This device is a surgical cutting guide, not an AI-assisted diagnostic or interpretation tool for human readers. Its evaluation would focus on the accuracy of the cuts, fit to anatomy, and ease of use in surgery, rather than improving human "reading" performance.

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

Standalone Performance: The device itself (the physical cutting guides) is the output of a CAD design process that utilizes patient imaging (CT scans) and an algorithm for sizing and positioning. The "software verification and validation" would assess the standalone performance of this design algorithm in terms of accurately generating the guides for the planned implant position. However, specific metrics for this standalone performance (e.g., precision of cuts, deviation from plan) are not detailed in this summary.

7. The type of ground truth used

Type of Ground Truth: For the "Implant sizing and positioning testing" and "Software verification and validation," the ground truth would likely be based on established anatomical landmarks, implant specifications, and potentially manual measurements or a "gold standard" 3D model derived from the patient's CT scan. For "Cadaver testing (surgeon evaluation and usability)," the ground truth would be based on surgical assessment of fit, alignment, and ease of use, likely against pre-defined surgical goals or standards.

8. The sample size for the training set

Training Set Sample Size: Not applicable or not provided. This device involves a patient-specific design process initiated from a CT scan for each individual patient, rather than a machine learning model that is trained on a large dataset and then applied. The underlying CAD design software is a rule-based or algorithmic system that may have been developed and validated over time, but the concept of a distinct "training set" in the context of an AI/ML model is not directly applicable here.

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

Training Set Ground Truth Establishment: Not applicable, as there is no explicitly mentioned "training set" in the context of an AI/ML model. The "ground truth" for the design software would be established through engineering design principles, anatomical studies, and clinical experience informing the parameters and rules within the CAD system.

Summary

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April 19, 2021

Conformis Inc. Mary Kruitwagen Sr. Regulatory Affairs Specialist 600 Technology Park Drive, 4th Floor Billerica, Massachusetts 01821

Re: K203421

Trade/Device Name: Triathlon AS-1 Regulation Number: 21 CFR 888.3560 Regulation Name: Knee Joint Patellofemorotibial Polymer Semi-Constrained Cemented Prosthesis Regulatory Class: Class II Product Codes: OOG, JWH Dated: March 30, 2021 Received: April 1, 2021

Dear Mary Kruitwagen:

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.

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valence determination does not mean that FDA

Page 2

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 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 mediation-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.

Peter G. Allen Digitally signed by Peter G. Date: 2021.04.19 13:33:19 -5 -04'00'

For: Ting Song, Ph.D., R.A.C. Assistant Director DHT6A: Division of Joint Arthroplasty Devices OHT6: Office of Orthopedic Devices Office of Product Evaluation and Ouality Center for Devices and Radiological Health

Enclosure

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Indications for Use

510(k) Number (if known) K203421

Device Name Triathlon AS-1

Indications for Use (Describe)

Type of Use (Select one or both, as applicable)
X Prescription Use (Part 21 CFR 801 Subpart D)	☐ Over-The-Counter Use (21 CFR 801 Subpart C)

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510(k) Number:	K203421
Submitter's Name and Address:	Conformis, Inc.600 Technology Park Drive, Fourth FloorBillerica, Massachusetts 01821USA
Establishment Registration Numbers(s):	3009844603 and 3004153240
Date Summary Prepared:	November 16, 2020
Contact Person:	Mary KruitwagenTitle: Senior Regulatory Affairs SpecialistTelephone: 781-345-9038Fax: 781-345-0147Email: Mary.Kruitwagen@conformis.com
Secondary Contact:	Kara JohnsonTitle: Director Regulatory AffairsTelephone: 781-832-5402Fax: 781-345-0147Email: Kara.Johnson@conformis.com
Trade Name/Device Name:	Triathlon AS-1
Common/ Usual Name:	Knee Arthroplasty Implantation System
Device Class:	II
Regulation Number:	21 CFR 888.3560
Regulation Description:	Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis.
Product Code:	OOG, JWH
Product Code Regulation :	21 CFR 888.3560
Product Code Device Name:	Knee Arthroplasty Implantation System
Legally Marketed Predicate Device:Primary Predicate:	510(k): K180906Device: iTotal® Cruciate Retaining (CR) Knee Replacement SystemSE Date: May 16, 2018Product codes: JWH, OIY, OOGClass: II

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Legally Marketed Predicate Device:	K201023
Secondary Predicate:

510(k):	K201023
Device:	iTotal® Identity Posterior Stabilized Knee Replacement
System
SE Date:	June 16, 2020
Product codes:	JWH, OIY, OOG
Class:	II

Device Description: The subject device, Triathlon AS-1, is a new Conformis Inc. device offering. The Triathlon AS-1 is comprised of patient matched single-use disposable cutting guides (also referred to as instruments or jigs) with corresponding surgical documentation which includes the Instructions for Use, Surgical Protocol and Surgical Plan. The single-use patient-matched instruments (including documentation) are similar to those of the legally marketed predicate device Knee Replacement Systems by Conformis Inc. (predicate devices K180906, K201023).

Each set of instruments is designed for single use, specifically for one patient. The disposable single-use instrument set is manufactured from biocompatible nylon material and supplied sterile.

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Indications For Use:	The Triathlon AS-1 patient-specific cutting guides are disposable, single-use surgical instruments intended to assist orthopedic surgeons in the positioning of femoral and tibial total knee arthroplasty components intraoperatively, provided that anatomic landmarks necessary for alignment and positioning of the implant are identifiable on patient imaging scans. They are intended for use with the Cruciate Retaining (CR), Condylar Stabilizing (CS), Posterior Stabilized (PS) and Tritanium® components of the Triathlon® Total Knee System and the Total Stabilizer (TS) and Posterior Stabilized Rotation (PSR) Triathlon® tibial inserts.
Summary of Intended Use/Indications for Use Differences	The subject device, single-use patient-matched instruments and the corresponding surgical documentation, is similar to the predicate iJigs provided with the Conformis Total Knee Replacement Systems. The predicate devices describe these similar instruments (iJigs) in their premarket submissions. The subject device performs the same function and has the same intended use as the iJigs in the predicate devices.
	The modifications to the single-use patient matched instruments do not raise any new issues with the safety or effectiveness as compared to the predicate single-use patient matched instruments. The cemented or uncemented implant fixation method has no bearing on the subject device.
	The differences in the wording of the subject device's Intended Use/Indications For Use statements do not represent a change from the Indications For Use or Intended Use of the predicate devices for the equivalent single-use patient matched instruments.
Summary of Technological Characteristics	There is no new technology employed as part of this subject device.
	The CAD design processes for the subject device are the similar to those employed for the predicate devices. The instrumentation has the same function and technological characteristics as those of the predicate devices. The subject device is composed of the same material that uses the same selective laser sintering manufacturing process as the predicate devices. The subject device uses the same packaging materials and sterilization methods as those of the predicate devices.
Substantial Equivalence:	The subject device is substantially equivalent to the predicate devices Conformis Total Knee Replacement System as described in their premarket submissions (K180906 and 201023). The following testing was conducted and used to establish substantial equivalence: Cadaver testing (surgeon evaluation and usability)Implant sizing and positioning testingSoftware verification and validation
Safety and Effectiveness Data	The assessment of the non-clinical data provided in this submission supports that the subject device is safe, effective and performs as well

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as the predicate device. No new issues of safety or effectiveness were raised.

Conclusion:

In conclusion, the information contained within this submission supports safety, effectiveness of this device and that it performs as well as the predicate device.

Regulation Number and Section

§ 888.3560 Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis.

(a)
Identification. A knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace a knee 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 a tibial component or components and a retropatellar resurfacing component made of ultra-high molecular weight polyethylene. This generic type of device is limited to those prostheses intended for use with bone cement (§ 888.3027).(b)
Classification. Class II.