The iTotal® CR Knee Replacement System (iTotal CR 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 knee compartments, such as a unicondylar, patello-femoral or bi-compartmental prosthesis. The indications for use include :

t 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, hemiarthoplasties, and unicondylar, . patello-femoral or bi-compartmental implants.
The iTotal CR KRS 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. The product design incorporates a bone preserving approach with minimal bone resection of the tibia and femur for the treatment of severe pain and/or disability of a knee damaged by osteoarthritis or trauma.
Using patient imaging (either CT or MR scans) and a combination of proprietary and off the shelf software a patient-specific implant is designed, that best meets the geometric and anatomic requirements of the specific patient. The femoral component is manufactured from cobalt chromium molybdenum ("CoCrMo") alloy. The tibial component includes a metal tray manufactured from CoCrMo alloy and two polyethylene inserts manufactured from UHMWPE. The patellar component is manufactured from UHMWPE.
For user convenience, and similar to the predicate iTotal CR KRS, accessory orthopedic manual surgical instruments designed for use with the modified iTotal CR KRS are provided to assist with implantation. The ancillary instruments are provided sterile and for single-use only. These patient specific instruments are provided to assist in the positioning of total knee replacement components intra-operatively and in guiding the marking of bone before cutting.

AI/ML Overview

The ConforMIS iTotal® CR Knee Replacement System is a patient-specific, semi-constrained, cemented knee implant. This device is intended for total knee replacement in patients suffering from knee joint pain and disability due to conditions like osteoarthritis, traumatic arthritis, rheumatoid arthritis, osteonecrosis, post-traumatic loss of joint function, moderate deformity, or failed prior implants. The submission for this modified device is a 510(k), indicating a claim of substantial equivalence to previously cleared predicate devices.

1. Table of Acceptance Criteria and Reported Device Performance

For this specific 510(k) submission (K120316), the "acceptance criteria" are not explicitly quantified in terms of performance metrics (e.g., accuracy, sensitivity, specificity). Instead, substantial equivalence is established through detailed device description and non-clinical laboratory testing demonstrating that the modifications do not raise new questions of safety or effectiveness compared to the predicate devices. The focus is on ensuring the modified device maintains the same safety and performance characteristics as the legally marketed predicate devices.

Acceptance Criteria Category	Specific Criteria (Implicit for Substantial Equivalence)	Reported Device Performance
Material Equivalence	Materials: Femoral, Tibial, Patellar components must be equivalent or validated.	Met: Materials (CoCrMo alloy, UHMWPE) are identical to the predicate device.
Design Equivalence	Design: Knee joint patellofemorotibial semi-constrained cemented prosthesis.	Met: Design remains a knee joint patellofemorotibial semi-constrained cemented prosthesis.
Principle of Operation	Principle: Cemented use, fixed bearing design.	Met: Operates with cemented use and fixed bearing design.
Patient Matched	Patient Matched: Yes	Met: Continues to be patient-matched.
Patellar Design/Dimensions	Patellar: Symmetrical, offered in various sizes.	Met: Patellar design is symmetrical and offered in various sizes.
Tibial Insert Thickness	Minimum thickness of Tibial Insert (UHMWPE): 6 mm	Met: Minimum tibial insert thickness remains 6 mm.
PCL Sparing	Posterior Cruciate Ligament (PCL) Sparing: Yes	Met: Continues to be PCL sparing.
Instrumentation	Instrumentation: Patient specific Nylon jigs.	Met: Uses patient specific Nylon jigs.
Functional Equivalence	Tibial interlock assembly and disassembly.	Met: Tibial tray/insert interlock assembly/disassembly testing performed.
Simulated Use Performance	Cadaveric testing demonstrating functionality and safety.	Met: Cadaveric testing performed.

The key modification in this submission, as highlighted in the device comparison, is a change in the Tibial Implant interlock design from "Interference fit Anterior lip Tray undercut design" to "Interference fit Anterior lip Double Undercut with Central Spine." The testing performed directly addresses this change.

2. Sample Size Used for the Test Set and Data Provenance

Test Set Sample Size: Not explicitly stated as part of a statistically powered clinical or performance study with a 'test set' in the traditional sense of a machine learning evaluation. For the non-clinical testing performed:
- Cadaveric testing: The specific number of cadaveric specimens used is not provided in the summary.
- Tibial interlock assembly and disassembly testing: The sample size for this mechanical test (e.g., number of interlocks tested) is not specified.
Data Provenance: Not applicable in this context, as the evaluation primarily involved mechanical and cadaveric bench testing, not patient data for algorithm performance.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

This information is not applicable. The device is a physical knee implant system, not a diagnostic or AI-driven decision support system that requires expert-established ground truth on a test set of images or clinical cases. The "ground truth" for the performance of the implant and instruments would be the successful mechanical and functional outcomes observed during the non-clinical testing.

4. Adjudication Method for the Test Set

This information is not applicable. There was no 'test set' that required adjudication by experts in the context of image interpretation or diagnostic performance. The evaluation was based on engineering design, material properties, and mechanical bench testing.

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 is not relevant here. This submission is for a physical orthopedic implant and its associated patient-specific instruments, not an AI-assisted diagnostic or image analysis tool.

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

This information is not applicable. The device itself is an implant. While patient-specific implants are designed "Using patient imaging (either CT or MR scans) and a combination of proprietary and off the shelf software," the performance evaluation described in this 510(k) summary focuses on the physical implant and instruments, not the standalone performance of the design software. The software's output is a physical design, which then undergoes manufacturing and testing.

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

The ground truth used for the non-clinical testing of the physical device would be based on:

Engineering specifications and standards: For the tibial interlock assembly/disassembly testing, the ground truth would be successful assembly, secure interlock, and resistance to disassembly forces as per design requirements and relevant ASTM standards (implied, not explicitly stated which ones).
Anatomical and biomechanical integrity: For cadaveric testing, the ground truth would be successful implantation, appropriate fit, alignment, and mechanical stability within the cadaveric knee, consistent with intended surgical outcomes and biomechanical principles.

8. The Sample Size for the Training Set

This information is not applicable. This is not an AI/machine learning submission with a 'training set' in the conventional sense. The "patient-specific implant is designed, that best meets the geometric and anatomic requirements of the specific patient" using proprietary software, but the validation presented here is for the physical device, not the training of the design algorithms.

9. How the Ground Truth for the Training Set Was Established

This information is not applicable as there is no 'training set' for an AI algorithm described in this 510(k) summary for the device itself. The software used for patient-specific design would have its own internal validation processes, but these are not within the scope of this 510(k) document which focuses on the equivalence of the modified physical implant.

Summary

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K120316	#/5 APR 19 2012
510(K) SUMMARY	4/13/12
Submitter's Nameand Address	ConforMIS Inc.11 North Ave.Burlington, MA 01803
EstablishmentRegistration Number	3004153240
Date of Summary	January 30, 2012
Contact Person	Amita S. Shah, Vice President, Quality Assurance & RegulatoryAffairs
Telephone Number	(781) 345-9164
Fax Number	(781) 345-0104
Name of the Device	ConforMIS iTotal® CR Knee Replacement System (iTotal CRKRS)
Common or UsualName	Cruciate Retaining Total Knee Replacement System
Classification Name	Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis
Regulation NumberDevice Classification	21 CFR 888.3560Product Code:JWH, Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis.OOG, Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis.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 establishing cuts,selecting, sizing, attaching, positioning or orienting implantcomponents.

1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 - 1999 -

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ConforMIS iTotal CR Knee Replacement System

4/13/12

510(k) Summary continued

Indications for Use

K120316

t 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, hemiarthoplasties, and unicondylar, . patello-femoral or bi-compartmental implants.

ConforMIS iTotal CR Knee Replacement System (ITOTAL CR

The iTotal CR KRS is intended for cemented use only.

ldentification of the Legally Marketed Device (Predicate Device)

KRS) Device Class: III Product Code: JWH, OOG Regulation Number: 21 CFR 888.3560 510(k) number: K103117,K094050 and K112780

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. The product design incorporates a bone preserving approach with minimal bone resection of the tibia and femur for the treatment of severe pain and/or disability of a knee damaged by osteoarthritis or trauma.

Using patient imaging (either CT or MR scans) and a combination of proprietary and off the shelf software a patient-specific implant is designed, that best meets the geometric and anatomic requirements of the specific patient. The femoral component is manufactured from cobalt chromium molybdenum ("CoCrMo") alloy. The tibial component includes a metal tray manufactured from CoCrMo alloy and two polyethylene inserts manufactured

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K120316

ConforMIS iTotal CR Knee Replacement System

4/13/12

from UHMWPE. The patellar component is manufactured from UHMWPE.

For user convenience, and similar to the predicate iTotal CR KRS, accessory orthopedic manual surgical instruments designed for use with the modified iTotal CR KRS are provided to assist with implantation. The ancillary instruments are provided sterile and for single-use only. These patient specific instruments are provided to assist in the positioning of total knee replacement components intra-operatively and in guiding the marking of bone before cutting.

The function and general design features of the patient specific ancillary instruments remain similar to those described in the predicate 510k i.e. K094050, K103117 and K112780.

The product subject of this premarket notification is substantially equivalent to the iTotal Cruciate Retaining Knee Replacement System (K094050 cleared September16, 2010, K103117 cleared January 7, 2011 and K112780 cleared December15, 2011) and other currently marketed, cemented total knee replacement systems. The following testing was performed to establish substantial equivalence:

Tibial interlock assembly and disassembly testing -

Design validation via cadaveric testing
Substantial Equivalence:

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K120316#4/5

K120316

ConforMIS iTotal CR Knee Replacement System

4/13/12

510(k) Summary continued

Device Comparison

	PredicateiTotal CR Knee ReplacementSystem(K103117)	Modified DeviceiTotal CR Knee ReplacementSystem(This submission)
Components	Femoral Component Tibial Implant Metal Backed Tibial Component Patellar component	Femoral Component Tibial Implant Metal BackedTibial Component Patellar component
Materials	Femoral Implant: CoCrMo Metal Backed Tibial Components: Tibial tray: CoCrMo Tibial Inserts: UHMWPE All Polymer Patellar Component:UHMWPE	Femoral Implant: CoCrMo Metal Backed Tibial Components: Tibial tray: CoCrMo Tibial Inserts: UHMWPE All Polymer Patellar Component:UHMWPE
Design	Knee joint patellofemorotibial semi-constrained cemented prosthesis	Knee joint patellofemorotibial semi-constrained cemented prosthesis
Principle ofOperation	Cemented Use fixed Bearing Design	Cemented Use fixed Bearing Design
Patient Matched	Yes	Yes
Patellar Design/Dimensions	Symmetrical, offered in various sizes	Symmetrical, offered in various sizes
Tibial Implantinterlock design	Interference fit Anterior lip Tray undercut design	Interference fit Anterior lip Double Undercut with Central Spine
MinimumThickness ofTibial Insert(UHMWPE)	6 mm	6 mm
Posterior CruciateLigament (PCL)Sparing	Yes	Yes
Instrumentation	Patient specific Nylon jigs	Patient specific Nylon jigs

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K1203/6 #5/5

K120316

ConforMIS iTotal CR Knee Replacement System

4/13/12

510(k) Summary continued

Description and Nonclinical Testing: The determination of substantial equivalence Conclusion of for this device was based on a detailed device description. The Testing following non-clinical laboratory testing was performed demonstrating that the device is safe and can be considered substantially equivalent to the predicate device for the intended use: Tibial tray/insert interlock assembly/disassembly testing . Cadaveric testing . Safety and The determination of substantial equivalence for this device was Performance based on a detailed device description. Non-clinical laboratory testing was performed demonstrating that the device is safe and can be considered substantially equivalent to the predicate device for the proposed intended use. Clinical data is not necessary to demonstrate substantial equivalence. Conclusion: Based on the testing conducted it is concluded that the modified device is substantially equivalent to the iTotal Cruciate Retaining Knee Replacement System, K094050 cleared September 16, 2010, K103117 cleared January 7, 2011 and K112780 cleared December15, 2011.

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Image /page/5/Picture/0 description: The image shows a partial view of a logo and some text. The logo is a circular emblem with a stylized image of an eagle or similar bird, surrounded by text that reads "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA". To the right of the logo, the word "DEPART" is visible, suggesting that the image is part of a larger document or graphic.

DEPARTMENT OF HEALTH & HUMAN SERVICES

Public Health Service

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

ConforMIS, Incorporated % Ms. Amita S. Shah 11 North Avenue Burlington, Massachusetts 01803

APR 1.9 2012

Re: K120316

Trade/Device Name: iTotal CR Knee Replacement System Regulation Number: 21 CFR 888.3560

Regulation Name: Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis

Regulatory Class: Class II Product Code: JWH. OOG Dated: January 30, 2012 Received: February 01, 2012

Dear Ms. Shah:

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 or uny I ederal 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 device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set

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Page 2 - Ms. Amita S. Shah

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.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please go to http://www.fda.gov/AboutFDA/CentersOffices/CDRH/CDRHOffices/ucm115809.htm for the Center for Devices and Radiological Health's (CDRH's) Office of Compliance. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR 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 Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/Resourcesfor You/Industry/default.htm.

Sincerely yours,

urs,

elkerson

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

Enclosure

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Indications for Use

510(k) Number (if known): K120316

Device Name: iTotal CR Knee Replacement System

Indications for Use:

The iTotal® CR Knee Replacement System (iTotal CR 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 knee compartments, such as a unicondylar, patello-femoral 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, hemiarthoplasties, and unicondylar, patello-femoral or bi-. compartmental implants.

The iTotal CR KRS is intended for cemented use only.

Over-The-Counter Use Prescription Use AND/OR (21 CFR 801 Subpart C) (Part 21 CFR 801 Subpart D) (PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE OF NEEDED)

Concurrence of CDRH, Office of Device Evaluation (ODE)

Oveal

(Division Sign-Off) Division of Surgical, Orthopedic, and Restorative Devices

510(k) Number

Special 510(k) - Modified iTotal® CR Knee Replacement System Page 24 of 86

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.