The iTotal Cruciate Retaining (CR) Knee Replacement System (KRS) 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, traumatic arthritis, rheumatoid arthritis or osteonecrosis of the knee.
• Post traumatic loss of joint function.
• Moderate varus, valgus or flexion deformity in which the ligamentous structures can be returned to adequate function and stability.
• 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

The iTotal CR Knee Replacement System (hereafter referred to as the "iTotal CR KRS") is a patient-specific, tricompartmental, faceted posterior cruciate ligament (PCL) retaining knee replacement system. The iTotal CR KRS is a semi-constrained, cemented knee implant which consists of a femoral, tibial, and patellar component.

Using patient imaging and a combination of proprietary and offthe-shelf software, a patient-specific implant is designed that best meets the geometric and anatomic requirements of the specific patient. The femoral implant is manufactured from cobalt chromium molybdenum (CoCrMo) alloy. The tibial component includes a metal tray manufactured from CoCrMo alloy and either one or two polyethylene inserts. The polyethylene inserts may be manufactured from either UHMWPE or iPoly® XE (a highly cross-linked vitamin E infused polyethylene) The patellar component may also be manufactured from either UHMWPE or iPoly® XE.

For user convenience, and similar to the predicate iTotal CR KRS, single-use, patient-specific ancillary orthopedic manual surgical instruments designed for use with the proposed iTotal CR KRS 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.

The function and general design features of the patient-specific implants and ancillary instruments remain similar to those described in the predicate 510(k), K161366.

AI/ML Overview

This document does not contain the detailed acceptance criteria or a study that proves the device meets specific performance criteria in the way typically expected for an AI/ML device.

The provided text is a 510(k) summary for the Conformis iTotal Cruciate Retaining (CR) Knee Replacement System. This document focuses on demonstrating substantial equivalence to a previously cleared predicate device (K161366) rather than establishing new performance metrics.

Here's a breakdown based on your requested information, highlighting what is and is not present in the provided text:

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

Not present in this document. This document does not establish specific performance acceptance criteria (e.g., accuracy, precision) for a medical image analysis algorithm or AI component in the typical sense. Instead, it focuses on demonstrating that the updated software produces results comparable to the predicate software and that the overall device design and materials remain unchanged.

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

Not present in this document. There is no mention of a test set sample size or data provenance as this 510(k) is not presenting a clinical performance study. The "test set" in this context refers to the software verification and validation testing, but no details on the data used are provided.

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)

Not present in this document. Ground truth for clinical performance is not discussed as there is no clinical performance study being presented. For software verification, ground truth would likely be based on engineering specifications or comparisons to output from the previous software version.

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

Not present in this document. Adjudication methods are typically relevant for clinical studies where expert consensus is needed to establish ground truth for ambiguous cases. This is not applicable to the type of submission described.

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

Not present in this document. This device is a knee replacement system, and the software components are for patient-specific implant design and surgical planning. It is not an AI-assisted diagnostic tool for human readers, so an MRMC study is not relevant here.

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

The document states "Software verification and validation testing of proprietary software" was performed. This implies standalone testing of the algorithm (software modules) to ensure they function as intended and produce expected outputs for implant design and surgical planning. However, no specific details of this testing are provided. The software's output (implant design and surgical plan) is ultimately used by human surgeons during the procedure.

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

For the "Software verification and validation testing," the ground truth would likely be based on:
- Engineering specifications: The software should produce designs that meet predefined geometric and functional requirements.
- Comparison to predicate software outputs: The updated software (iTotalWorks 6.0, iTotalFem CR 1.0, iTotalTib CR 5.0, iTotal CR iView 4.0) should produce designs and plans that are equivalent or demonstrate appropriate improvements compared to the predicate software (iTotalWorks 5.1, iTotal FemJigs 3.0, iTotalTib CR 4.3, iTotal CR iView 3.0). The purpose of the changes is to improve manufacturing efficiencies through automation, implying the output should remain consistent with the validated predicate.
No clinical "ground truth" (pathology, outcomes data) is mentioned as it's not a diagnostic device.

8. The sample size for the training set

Not applicable/Not present. This document discusses a change in software versions (i.e., v5.1 to v6.0 for iTotalWorks, etc.) for a workflow that custom designs existing implants. It is not describing a machine learning model that was specifically "trained" on a dataset in the way an AI diagnostic algorithm would be. The "proprietary and off-the-shelf software" uses patient imaging to design a patient-specific implant based on pre-defined algorithms and rules, not necessarily a training phase with a distinct training set.

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

Not applicable/Not present. As there's no explicitly defined "training set" in the context of an AI/ML model for this device, there's no discussion of how ground truth for such a set was established.

In summary:

This 510(k) pertains to a knee replacement system where the software is used for patient-specific implant design and surgical planning. The submission is a modification to an already cleared device and focuses on demonstrating that changes to the software modules for CAD manufacturing processes do not alter the substantial equivalence of the device to its predicate. The "study" mentioned is "Software verification and validation testing of proprietary software," which ensures the new software performs as intended and produces results consistent with the previously cleared versions. This is a technical (engineering) validation rather than a clinical performance study with human readers or AI diagnostic capabilities.

Summary

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May 16, 2018

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Conformis, Inc. Emmanuel Nyakako Sr. Vice President, Quality and Regulatory 600 Technology Park Drive, 4th Floor Billerica, Massachusetts 01821

Re: K180906

Trade/Device Name: Conformis iTotal Cruciate Retaining (CR) 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, OOG, OIY Dated: April 4, 2018 Received: April 6, 2018

Dear Emmanuel Nyakako:

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 of medical device-related adverse events) (21 CFR 803); 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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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.

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/DeviceRegulationandGuidance/) and CDRH Learn (http://www.fda.gov/Training/CDRHLearn). 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 (http://www.fda.gov/DICE) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely,

Mark N. Melkerson -S

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

Enclosure

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Indications for Use

510(k) Number (if known) K180906

Device Name

Conformis iTotal Cruciate Retaining (CR) Knee Replacement System

Indications for Use (Describe)

The Indications for Use include:

Painful joint disease due to osteoarthritis, traumatic arthritis, rheumatoid arthritis or osteonecrosis of the knee.
· Post traumatic loss of joint function.

· Moderate varus, valgus or flexion deformity in which the ligamentous structures can be returned to adequate function and stability.

· 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 (PAGE 1 OF 5)

Submitter's Name andAddress:	Conformis, Inc.600 Technology Park Dr.Billerica, MA 01821
EstablishmentRegistration Number:	3009844603 and 3004153240
Date 510(k) Summarywas Prepared:	April 4, 2018
Contact Person:	Emmanuel O. Nyakako, Sr. Vice President, Quality andRegulatory
Telephone Number:Fax Number:	(781) 345-9164(781) 345-0147
Name of the Device(s):	Conformis® iTotal® Cruciate Retaining Knee ReplacementSystem (iTotal CR KRS)
Common Name(s):	Knee Replacement System
Regulatory Status andRegulation Number:	Class II21 CFR 888.3560
Classification Name:	Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis
Device Classification:	Product Codes:JWH: Knee joint patellofemorotibial polymer/metal/polymersemi-constrained cemented prosthesis.OOG: Knee Arthroplasty Implantation System.Intended to be used to assist in the implantation of a specific kneearthroplasty device or a set of specific knee arthroplasty devices.Indicated to include guiding alignment, making or establishingcuts, selecting, sizing, attaching, positioning or orienting implantcomponents.OIY: Prosthesis, knee, patellofemorotibial, semi-constrained,cemented, polymer + additive/metal/polymer + additive. Thisgeneric type of device includes prostheses that have a femoralimplant made of alloys, such as cobalt-chromium-molybdenum,and a tibial component(s) and/or a retropatellar resurfacingcomponent made of ultra-high molecular weight polyethyleneplus an additive, such as a-tocopherol.
Indications for Use:	The iTotal Cruciate Retaining (CR) Knee Replacement System(KRS) is intended for use as a total knee replacement in patientswith knee joint pain and disability whose conditions cannot besolely addressed by the use of a prosthetic device that treats onlyone or two of the three knee compartments, such as aunicondylar, patellofemoral or bicompartmental prosthesis.The Indications for Use include:• Painful joint disease due to osteoarthritis, traumatic arthritis,rheumatoid arthritis or osteonecrosis of the knee.• Post traumatic loss of joint function.• Moderate varus, valgus or flexion deformity in which theligamentous structures can be returned to adequate functionand stability.• Failed osteotomies, hemiarthroplasties, and unicondylar,patellofemoral or bicompartmental implants.• Revision procedures provided that anatomic landmarksnecessary for alignment and positioning of the implant areidentifiable on patient imaging scans.This implant is intended for cemented use only.
Identification of the	Conformis iTotal CR Knee Replacement System (iTotal CRKRS)
Legally Marketed
Device(s) (Predicate	Device Class: II
Device(s)):	Product Code: JWH, OOG, OIY
	Regulation Number: 21 CFR 888.3560

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510(K) SUMMARY (PAGE 2 OF 5)

510(k) Number:

K161366

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510(K) SUMMARY (PAGE 3 OF 5)

Device Description: The iTotal CR Knee Replacement System (hereafter referred to as the "iTotal CR KRS") is a patient-specific, tricompartmental, faceted posterior cruciate ligament (PCL) retaining knee replacement system. The iTotal CR KRS is a semi-constrained, cemented knee implant which consists of a femoral, tibial, and patellar component.

Using patient imaging and a combination of proprietary and offthe-shelf software, a patient-specific implant is designed that best meets the geometric and anatomic requirements of the specific patient. The femoral implant is manufactured from cobalt chromium molybdenum (CoCrMo) alloy. The tibial component includes a metal tray manufactured from CoCrMo alloy and either one or two polyethylene inserts. The polyethylene inserts may be manufactured from either UHMWPE or iPoly® XE (a highly cross-linked vitamin E infused polyethylene) The patellar component may also be manufactured from either UHMWPE or iPoly® XE.

For user convenience, and similar to the predicate iTotal CR KRS, single-use, patient-specific ancillary orthopedic manual surgical instruments designed for use with the proposed iTotal CR KRS 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.

The function and general design features of the patient-specific implants and ancillary instruments remain similar to those described in the predicate 510(k), K161366.

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510(K) SUMMARY (PAGE 4 OF 5)

Comparison Summary of Technological Characteristics and Modifications Proposed:

The proposed iTotal CR KRS and predicate iTotal CR KRS have the same technological characteristics. There have been no changes to the proposed iTotal CR KRS device with respect to design, materials or methods of manufacture, packaging, or sterilization.

Modifications, which represent improving manufacturing efficiencies, are primarily focused on increasing automation of the CAD manufacturing processes via the proprietary software modules as shown in Table 8-1 below.

Characteristic	PredicateiTotal CR KRS(K161366)	ProposediTotal CR KRS
Generation ofFemoral Implant	iTotalWorks 5.1 andFem Addin orManual CADProcess	iTotalWorks 6.0 &iTotalFem CR 1.0 orManual CADProcess
Generation ofFemoral iJigs	iTotalWorks 5.1 &iTotal FemJigs 3.0or Manual CADProcess	iTotalWorks 6.0 andiTotalFem CR 1.0 orManual CADProcess
Generation of TibialImplants and iJigs	iTotalTib CR 4.3 orManual CADProcess	iTotalTib CR 5.0 orManual CADProcess
Generation ofPatient-SpecificSurgical Plan(iView)	iTotal CR iView 3.0or Manual CADProcess	iTotal CR iView 4.0or Manual CADProcess

Table 8-1: Comparison Between the Proposed and Predicate Device

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510(K) SUMMARY (PAGE 5 OF 5)

Substantial Equivalence:	The determination of substantial equivalence for this device wasbased on a detailed device description. Non-clinical laboratorytesting was performed demonstrating that the device can beconsidered substantially equivalent to the predicate device for itsintended use. The following non-clinical laboratory testing wasperformed:Software verification and validation testing ofproprietary software
Conclusion:	Based on the testing conducted, it is concluded that the proposed

iTotal Cruciate Retaining Knee Replacement System is substantially equivalent to the predicate iTotal Cruciate Retaining Knee Replacement System (K161366, cleared June 14, 2016).

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.