The iTotal Identity Posterior Stabilized Knee Replacement System is intended for use as a total knee replacement in patients with knee joint pain and disability whose conditions cannot be solely addressed by the use of a prosthetic device that treats only one or two of the three compartments, such as a unicondylar, patellofemoral or bicompartmental prosthesis.

The Indications for Use include:

· Painful joint disease due to osteoarthritis, traumatoid arthritis, polyarthritis, polyarthritis or osteonecrosis of the knee.

· Post traumatic loss of joint function.
· Moderate varus, valgus or flexion deformity.
· Failed osteotomies, hemiarthroplasties, and unicondylar, patellofemoral or bicompartmental implants.

· Revision procedures provided that anatomic landmarks necessary for alignment and positioning of the implant are identifiable on patient imaging scans.

This implant is intended for cemented use only.

Device Description

Conformis knee replacement systems are patient-specific semi-constrained knee implants which consist of a femoral, tibial, and/or patellar components. The products are intended for treatment of severe pain and/or disability of the knee damaged by osteoarthritis or trauma.

Using patient imaging (either CT or MR scans), a patient-specific implant is designed that best meets the geometric and anatomic requirements of the specific patient. The femoral components of the subject devices are manufactured from cobalt chromium molybdenum (CoCrMo) alloy. The tibial component includes a metal tray manufactured from titanium alloy and polyethylene inserts. The patellar components are manufactured from UHMWPE.

For user convenience, single-use, patient-specific ancillary orthopedic manual surgical instruments designed for use with the proposed iTotal Identity Posterior Stabilized Knee Replacement System are provided to assist in the positioning of the total knee replacement components intraoperatively and in guiding the cutting of bone. In addition, reusable orthopedic manual surgical instruments are provided separately.

AI/ML Overview

This FDA document is a 510(k) summary for a medical device called the "iTotal Identity Posterior Stabilized Knee Replacement System." It describes the device, its intended use, and argues for its substantial equivalence to previously cleared devices.

However, the document does not contain the kind of information typically found in a study proving a device meets specific acceptance criteria based on performance metrics like sensitivity, specificity, or accuracy. This is a notification of intent to market, and its primary purpose is to demonstrate "substantial equivalence" to existing cleared devices, not to present a de novo clinical or algorithm performance study.

Therefore, for the information requested in your prompt, I can only provide what is explicitly stated or can be reasonably inferred from the document. Many of your requested points, especially those related to AI/algorithm performance studies, ground truth establishment, expert adjudication, and detailed statistical metrics, are not present in this type of FDA submission.

Here's a breakdown based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

This document does not present acceptance criteria in the typical sense of numerical performance targets (e.g., sensitivity > X%, specificity > Y%). Instead, the "performance" is assessed through non-clinical confirmatory testing to ensure safety and functionality.

Acceptance Criteria (Implied by testing standards)	Reported Device Performance (Conclusion)
Meets ASTM F1814 and ASTM F2083 for insert interlock/modularity	Confirmatory testing was performed. Conclusion: Device is substantially equivalent to predicates. Implies compliance with these standards.
Meets ASTM F1800 and ASTM F2083 for tibial tray fatigue	Confirmatory testing was performed. Conclusion: Device is substantially equivalent to predicates. Implies compliance with these standards.
Meets criteria for simulated use	Confirmatory testing was performed. Conclusion: Device is substantially equivalent to predicates. Implies satisfactory performance.
Meets ASTM F2052-14, ASTM F2213-06, ASTM F2182-11a, and ASTM F2119-07 for MR Compatibility	Confirmatory testing was performed. Conclusion: Device is substantially equivalent to predicates. Implies compliance with these standards.

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

Sample size for test set: Not specified. The document refers to "confirmatory testing" but does not detail the number of units or conditions tested for each non-clinical performance evaluation.
Data provenance: Not applicable in the sense of patient data. The testing mentioned is non-clinical/bench testing of the device components.

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

This information is not applicable and not present in the document. The "ground truth" for non-clinical testing typically involves engineering specifications and compliance with standardized test methods, not expert clinical interpretation.

4. Adjudication method for the test set

Not applicable and not present. Adjudication methods (like 2+1, 3+1) are common in clinical studies where human interpretation or consensus is needed for a "ground truth." This document describes non-clinical engineering tests.

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

No, an MRMC comparative effectiveness study was not done. This document describes a new knee replacement system, which is a physical implant, not an AI or imaging diagnostic tool that would typically involve human readers or AI assistance in interpretation.

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

No, a standalone algorithm performance study was not done. This device is a knee implant, not an algorithm. While its design involves "patient-specific implant [design] that best meets the geometric and anatomic requirements of the specific patient" using "patient imaging (either CT or MR scans)", the document focuses on the implant and its physical performance, not on the performance of a standalone algorithm for diagnosis or image interpretation.

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

For the non-clinical performance evaluations, the "ground truth" is established by the engineering specifications and the requirements of the ASTM (American Society for Testing and Materials) standards referenced (e.g., F1814, F2083, F1800, F2052-14). These standards define acceptable performance metrics for various aspects of orthopaedic implants.

8. The sample size for the training set

Not applicable/not specified. Since this is a physical medical device (knee implant) and not an AI algorithm being "trained," there is no concept of a training set in the context of device performance as requested in your prompt. The patient imaging data mentioned is used for individual patient-specific design rather than training a general algorithm.

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

Not applicable. See point 8.

Summary

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June 16, 2020

Image /page/0/Picture/1 description: The image shows the logo of the U.S. Food and Drug Administration (FDA). The logo consists of two parts: the Department of Health & Human Services logo on the left and the FDA acronym with the full name of the agency on the right. The FDA part of the logo is in blue, with the acronym in a larger font size than the full name. The full name of the agency is "U.S. Food & Drug Administration".

Conformis, Inc. Nancy Giezen Manager Regulatory Affairs 600 Technology Park Drive Billerica, Massachusetts 01821

Re: K201023

Trade/Device Name: iTotal Identity Posterior Stabilized Knee Replacement System Regulation Number: 21 CFR 888.3560 Regulation Name: Knee Joint Patellofemorotibial Polymer Semi-Constrained Cemented Prosthesis Regulatory Class: Class II Product Code: JWH, OIY, OOG Dated: April 15, 2020 Received: April 20, 2020

Dear Nancy Giezen:

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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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 (OS) 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.

Ting Song, Ph.D., R.A.C. Acting Assistant Director DHT6A: Division of Joint Arthroplasty 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) K201023

Device Name

iTotal Identity Posterior Stabilized Knee Replacement System

Indications for Use (Describe)

The Indications for Use include:

· Painful joint disease due to osteoarthritis, traumatoid arthritis, polyarthritis, polyarthritis or osteonecrosis of the knee.

· Post traumatic loss of joint function.
· Moderate varus, valgus or flexion deformity.
· Failed osteotomies, hemiarthroplasties, and unicondylar, patellofemoral or bicompartmental implants.

· Revision procedures provided that anatomic landmarks necessary for alignment and positioning of the implant are identifiable on patient imaging scans.

This implant is intended for cemented use only.

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)

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510(k) SUMMARY

Submitter's Name and Address:	Conformis, Inc.600 Technology Park DriveBillerica, MA 01821
Establishment Registration Number(s):	3009844603 and 3004153240
Date Summary was Prepared:	June 10th, 2020
Contact Person:	Nancy GiezenManager Regulatory AffairsTelephone: 781-345-9058

Trade/Device Name(s): iTotal Identity Posterior Stabilized Knee Replacement System

Common Name: Knee Replacement System

Device Class: Class II

Regulation Numbers: 888.3560

Classification Names and Product Codes:

Prosthesis, Knee, Patellofemorotibial, Semi-Constrained, Cemented, Polymer/Metal/PolymerKnee Arthroplasty Implantation System; JWH, OIY, OOG

Legally Marketed Predicate Device (Primary Predicate): iTotal Posterior Stabilized (PS) Knee Replacement System (K161668, K193105)

(Secondary Predicates):

iTotal Identity Cruciate Retaining (CR) Knee Replacement System (K190562) iTotal Cruciate Retaining (CR) Knee Replacement System (K193105) DePuy PFC Sigma Knee Prosthesis (K952830, K060515)

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Device Description:

Indications for Use:

The iTotal Identity Posterior Stabilized Knee Replacement System is intended for use as a total knee replacement in patients with knee joint pain and disability whose conditions cannot be solely addressed by the use of a prosthetic device that treats only one or two of the three knee compartments, such as a unicondylar, patellofemoral or bicompartmental prosthesis.

The Indications for Use include:

· Painful joint disease due to osteoarthritis, traumatic arthritis, rheumatoid arthritis, polyarthritis or osteonecrosis of the knee.
· Post traumatic loss of joint function.
· Moderate varus, valgus or flexion deformity.
· Failed osteotomies, hemiarthroplasties, and unicondylar, patellofemoral or bicompartmental implants.
· Revision procedures provided that anatomic landmarks necessary for alignment and positioning of the implant are identifiable on patient imaging scans.

This implant is intended for cemented use only.

Technological Characteristics:

The subject devices incorporate updates to the material and design which are consistent with previously cleared devices. The operating principle, fundamental technology, manufacturing methods and sterilization options are the same as the predicates.

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Non-Clinical Performance Evaluation:

The following confirmatory testing was performed:

Insert interlock/Modularity per ASTM F1814 and ASTM F2083 ●
Tibial Tray Fatigue per ASTM F1800 and ASTM F2083 ●
Simulated Use Testing ●
MR Compatibility per ASTM F2052-14, ASTM F2213-06, ASTM F2182-11a, and ASTM F2119-07

Conclusion:

Based on a comparison of the intended use and technological characteristics to predicate devices and on the results of confirmatory testing it is concluded that the proposed iTotal Identity Posterior Stabilized Knee Replacement System is substantially equivalent.

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.