Knee+ is a stereotaxic system including an intraoperative software as a medical device and surgical instruments. Knee+ is intended for primary Total Knee Replacement, to assist the surgeon in determining reference alignment axes in relation to anatomical landmarks, in order to position the cutting computed mechanical axis. The Knee+ includes smart glasses as a Head Mounted Device (HMD) for displaying information to the user intraoperatively. The smart glasses should not be relied upon solely and should always be used in conjunction with traditional methods.

Device Description

The main purpose of Knee+ is to assist the surgeon during the primary Total Knee Replacement (TKR) intervention. Knee+ includes software and surgical instruments.

Knee+ provides information to help locate and orientate the main femoral and tibial cutting planes as required in knee replacement surgery. Knee+ allows the surgeon to adjust the cutting plane orientation and the resection level. This includes means for the surgeon to collect anatomical references during the TKR intervention using the surgical instruments. The software locates in a 3D reference frame the instruments which include markers. All collected coordinates are treated by software algorithms to provide the surgeon with relevant orientation of the tracked cutting guide. Knee+ software is installed on a wearable Head Mounted Device (HMD) which includes a camera and displays intraoperative information to the user. A near-eye display allows the surgeon to look at the HMD screen or the field of view when needed.

AI/ML Overview

The provided text is a 510(k) summary for the medical device Knee+, documenting its substantial equivalence to a previously cleared version (K220104). The primary change in the subject device is the addition of an external camera to the Head-Mounted Device (HMD) for use under surgical helmets.

The document does not contain the detailed acceptance criteria or a comprehensive study report outlining the acceptance criteria and the performance data that proves the device meets those criteria in the format requested. While it refers to "performance data" and "acceptance criteria" from previous submissions, and mentions specific tests like ASTM F2554, it does not provide the specific numerical acceptance thresholds or the measured device performance against those thresholds in tabular format.

Therefore, I cannot fully answer your request by extracting the information directly from the provided text. The document states that "The same methods, protocols and acceptance criteria used to support the previously cleared K220104 were applied to evaluate the change." This implies that the specific details you're looking for would be in the K220104 submission, not in this K230789 summary.

However, I can extract and present the available relevant information regarding the study and testing performed to demonstrate substantial equivalence for the modifications in K230789:

Acceptance Criteria and Device Performance (Based on available information for K230789 modifications):

The document states that the same performance is still achieved with the modifications, and that "All performance testing demonstrates that Knee+ performs according to its specifications and functions as intended." While specific numerical criteria and reported performance values are not provided in this summary, the general areas of assessment and the type of criteria implicitly met are:

Acceptance Criterion (Implicit/General)	Reported Device Performance (as stated in summary)
Repeatability (per ASTM F2554)	"Demonstrate that Knee+ performs according to its requirements and specifications when installed on the Head Mounted Device under a surgical helmet... repeatability was tested according to ASTM F2554." (Results deemed satisfactory as per conclusion of substantial equivalence)
Accuracy (per ASTM F2554)	"Demonstrate that Knee+ performs according to its requirements and specifications when installed on the Head Mounted Device under a surgical helmet... accuracy were tested according to ASTM F2554." (Results deemed satisfactory as per conclusion of substantial equivalence)
User Needs Validation (per IEC 62366-1)	"The system was validated in accordance with IEC 62366-1 by the intended users to ensure that the installation of the modified Head-Mounted Device and the user underneath surgical helmets do not raise new issues of safety or effectiveness."
Software Verification and Validation (per IEC 62304 & FDA Guidance)	"Software verification and validation testing were conducted as required by IEC 62304 and documentation was provided as recommended by FDA Guidance 'Content of Premarket Submissions for Software Contained in Medical Devices'." (Results deemed satisfactory towards safety and effectiveness)
Overall Safety and Effectiveness	"Performance data demonstrated that Knee+ is as safe and effective as its previous version... Thus, the Knee+ is substantially equivalent to the legally marketed predicate device."

Study Details for K230789 (Focused on the modifications):

Sample size used for the test set and the data provenance:
- Sample Size: Not explicitly stated in terms of number of cases or subjects. For bench testing (ASTM F2554), it would typically involve multiple measurements or runs. For user needs validation, it would involve a group of "intended users." The exact number is not provided.
- Data Provenance: The studies were performance bench testing and user validation studies conducted by the manufacturer, Pixee Medical. The text doesn't specify the country of origin of the data beyond "Besançon, FRANCE" as the submitter's address. The studies were likely prospective for the purpose of validating the new modification.
Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Number of Experts: Not specified.
- Qualifications of Experts: For the "User needs validation," the validation was performed by "intended users." While their specific qualifications (e.g., orthopedic surgeons) are not explicitly stated, it can be inferred that they are medical professionals who would use the device (i.e., surgeons). For bench testing, the "ground truth" would be established by the highly accurate measurement tools and methods used within the testing lab.
Adjudication method for the test set:
- Not specified. Given the nature of bench testing and user needs validation in 510(k) submissions for modifications, formal multi-reader adjudication methods (like 2+1 or 3+1 often seen in diagnostic AI studies) are not typically described in this context for performance of the device's measurement capabilities. User needs validation would involve assessing user feedback and observations.
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 explicitly stated or implied for this 510(k) submission. This submission focuses on demonstrating that the modified device maintains its previous performance and does not introduce new safety or effectiveness concerns, specifically regarding the addition of an external camera and use under surgical helmets. The device's primary function is to assist in surgical navigation, providing information, and the study did not aim to measure human reader improvement with AI assistance.
If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- The document implies that standalone performance was assessed for the tracking system technology and accuracy of cut orientation and resection level through "Bench testing." This type of testing evaluates the algorithm's performance and the system's accuracy independent of a complex human interaction scenario, although it's within a controlled test environment.
The type of ground truth used:
- For accuracy and repeatability (bench testing): The ground truth would be established by highly precise measurement instruments and reference standards (e.g., calibrated optical tracking systems, mechanical fixtures) that are part of the ASTM F2554 testing methodology.
- For user needs validation: The ground truth is the qualitative assessment of safety, effectiveness, and usability by the intended users in simulated or actual usage scenarios.
The sample size for the training set:
- Not applicable / Not provided. The document describes a 510(k) submission for a modification to an already cleared device. It does not contain information about the training set size for the underlying algorithms, as this would have been established during the development and clearance of the original (K220104) or even earlier versions. The current submission focuses on verifying that the modification does not negatively impact existing performance.
How the ground truth for the training set was established:
- Not applicable / Not provided. As mentioned above, this information pertains to the original algorithm's development, not the current modification's validation.

Summary

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April 21, 2023

Pixee Medical Lucie Pécheur Regulatory Affairs Manager 14 rue Alain Savary Besancon, 25000 France

Re: K230789

Trade/Device Name: Knee+ Regulation Number: 21 CFR 882.4560 Regulation Name: Stereotaxic Instrument Regulatory Class: Class II Product Code: OLO Dated: March 17, 2023 Received: March 22, 2023

Dear Lucie Pécheur:

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 (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 -S

Shumaya Ali, M.P.H. Assistant Director DHT6C: Division of Restorative, Repair and Trauma 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) K230789

Device Name Knee+

Indications for Use (Describe)

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

Pixee Medical's Kneet

510(k) Submitter:

Name: Pixee Medical Address: 18 rue Alain Savary 25000 Besançon FRANCE

Phone: (+33) 4 58 10 13 65 Fax: (+33) 4 58 10 14 51

Contact Person: Lucie Pecheur

Date Prepared: March 17, 2023

Device:

Trade name: Kneet Common name: Surgical Navigation Software and Instruments Classification name: Orthopedic Stereotaxic Instrument (21 CFR §882.4560) Product code: OLO Regulatory class: II Classification Panel: Orthopedic

Predicate Device:

Knee* is substantially equivalent to the previous version of Knee*, leqally marketed:

Applicant Name	Device Name	Product code	510(k) number
Pixee Medical	Knee+	OLO	K220104

No reference devices were used in this submission.

Device Description:

The main purpose of Knee* is to assist the surgeon during the primary Total Knee Replacement (TKR) intervention. Knee* includes software and surgical instruments.

Knee* provides information to help locate and orientate the main femoral and tibial cutting planes as required in knee replacement surgery. Knee* allows the surgeon to adjust the cutting plane orientation and the resection level. This includes means for the surgeon to collect anatomical references during the TKR intervention using the surgical instruments. The software locates in a 3D reference frame the instruments which include markers. All collected coordinates are treated by software algorithms to provide the surgeon with relevant orientation of the tracked cutting guide. Kneet software is installed on a wearable Head Mounted Device (HMD) which includes a camera

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and displays intraoperative information to the user. A near-eye display allows the surgeon to look at the HMD screen or the field of view when needed.

Intended Use / Indications for Use:

Kneet is a stereotaxic system including an intraoperative software as a medical device and surgical instruments. Kneet is intended for primary Total Knee Replacement, to assist the surgeon in determining reference alignment axes in relation to anatomical landmarks, in order to position the cutting guide regarding computed mechanical axis. The Knee* includes smart glasses as a Head Mounted Device (HMD) for displaying information to the user intraoperatively. The smart glasses should not be relied upon solely and should always be used in conjunction with traditional methods.

Summary of Technological Characteristics:

The device subject of this Premarket Notification is a modification from the device legally authorized under K220104, also manufactured by Pixee Medical.

There are no differences between the subject device and the predicate (previous version of the device) with respect to indications and intended use.

The main change from the previous version (K220104) is the addition of an external camera to the Head-Mounted Device (HMD) in order to use Knee* device underneath surgical helmets.

Consequently, the installation of the Head Mounted Device under the surgical helmet is a new step of the usage workflow. Nevertheless, this step is performed before starting the surgery, and the successive steps of the surgical workflow remain the same as the cleared K220104. The information is still provided to the user through the near-eye display of the Head-Mounted Device.

The tracking system technology, the use of a Head Mounted Device to provide information and the claimed accuracy for cut orientation and resection level also remain the same as the most recent cleared version (K220104).

The main change as well as other minor changes were assessed through risk management activities, including relevant verification and validation information, produced under design controls procedures. The results of the design controls activities were provided as a summary in the Premarket Notification.

Substantial equivalence was therefore supported by performance data which demonstrated that the modified Knee* device is still safe and effective for its intended use. The differences from the previous version do not raise any concerns regarding the safety and effectiveness of the device.

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Non-Clinical Performance Data:

Performance data were necessary to demonstrate that the same performance is still achieved with the use of the external camera, under a surgical helmet. The same methods, protocols and acceptance criteria used to support the previously cleared K220104 were applied to evaluate the change, as well as FDA-recognized standards methods (well-established methods):

. Bench testing was conducted in order to demonstrate that Knee* performs according to its requirements and specifications when installed on the Head Mounted Device under a surgical helmet. In particular, repeatability and accuracy were tested according to ASTM F2554.
. User needs validation - The system was validated in accordance with IEC 62366-1 by the intended users to ensure that the installation of the modified Head-Mounted Device and the user underneath surgical helmets do not raise new issues of safety or effectiveness.
. Software verification and validation testing were conducted as required by IEC 62304 and documentation was provided as recommended by FDA Guidance "Content of Premarket Submissions for Software Contained in Medical Devices".

All performance testing demonstrates that Knee* performs according to its specifications and functions as intended.

Conclusion:

Kneet has the same intended use, indications for use and technological characteristics as its predicate device (i.e., the most recent cleared version K220104). The addition of an external camera to the Head-Mounted Device and other minor modifications do not alter the intended surgical use of the device and do not raise new questions of safety and effectiveness. Performance data demonstrated that Knee* is as safe and effective as its previous version, also manufactured by Pixee Medical. Thus, the Kneet is substantially equivalent to the legally marketed predicate device.

Regulation Number and Section

§ 882.4560 Stereotaxic instrument.

(a)
Identification. A stereotaxic instrument is a device consisting of a rigid frame with a calibrated guide mechanism for precisely positioning probes or other devices within a patient's brain, spinal cord, or other part of the nervous system.(b)
Classification. Class II (performance standards).