The X-PSI Knee System is indicated as an orthopedic instrument system to assist in the positioning of knee replacement components. It involves surgical planning software used pre-operatively to plan the surgical placement of the components on the basis of provided patient radiological images and 3-D reconstructed bones with identifiable placement anatomical landmarks, and surgical instrument components that include patient specific or customized guides fabricated on the basis of the surgical plan to precisely reference the placement of the implant components intra-operatively per the surgical plan. The X-PSI Knee system is indicated for patients without severe bone deformities, such as a HKA greater than 15° or deformities due to prior fracture of the distal femur or proximal tibia.

The X-PSI Knee System is to be used with the following fixed bearing knee replacement systems in accordance with their indications and contraindications: NexGen® CR, NexGen CR-Flex Gender, NexGen LPS, NexGen LPS-Flex, NexGen LPS-Flex Gender, Persona® CR, Persona PS, Vanguard® CR and Vanguard PS.

The patient specific guide components are intended for single-use only.

Device Description

The present Zimmer Biomet® X-PSI Knee System is an instrumentation system that includes customized surgical guides to mate each patient's bony and articular surface topographies to reference the location and orientation of the implant system's instruments which in turns sets the position and alignment of the femoral and tibial implant components.

It involves the following:

A CAS X-PSI Knee Software Suite used in preparation for the surgery to sequentially construct 3-D surface models of each patient's knee joint bony structures and articular surfaces from the patient's X-Ray images, plan the location and orientation of the knee replacement implant components upon the patient's model, and create the corresponding specification models for the patient specific surgical guides (PSI Guides) with surfaces and elements to uniquely fit each patient topographical features and set or reference the placement of the implant system components per the plan,
. The Zimmer Biomet ® X-PSI Guides (also called jigs) that are manufactured per the above models and plan, for intra-operative and single use, which include one to set the placement of the distal femoral cut guides which set the resection depth, the varus/valgus and the flexion of the distal cut and one to set the placement of the tibial cut guides which set the resection depth, the varus/valgus, and the posterior slope of the proximal cut.
. Each patient's Zimmer Biomet ®3-D Bone Models (femur and tibia components) that are fabricated and provided along with the PSI Guides for use intra-operatively to provide the surgeon with an intra-operative visual reference of the planned location of the PSI Guides in order to help guide their locations on the patient's actual joint,
Zimmer Biomet X-PSI Reusable Surgical Instrumentations are provided both sterile . and non-sterile and are reusable for intra-operative use, which include femoral stylus, and femoral and tibial cut block instrumentations to allow setting the resection level and performing the bone cuts as defined by the PSI Guides.
Fixation Pins are accessories for use of the guides, these accessories are Class I devices under the classification "Orthopedic manual surgical instrument (21 CFR § 888.4540)".

The Zimmer Biomet® X-PSI Knee System is compatible for use with the following class II Zimmer Biomet Nexgen, Persona and Vanguard total knee replacement implant systems:

. NexGen®family: NexGen CR, NexGen CR-Flex, NexGen CR-Flex Gender, NexGen LPS, NexGen LPS-Flex, NexGen LPS-Flex Gender
. Persona® family: Persona CR, Persona PS
Vanguard® family: Vanguard CR, Vanguard PS

Finally, the following accessories are used for the acquisition of the x-ray images:

X-Ray Marker 3D Zimmer Biomet ® X-PSI (re-usable) ●
X-Ray Calibration Straps, Short and Long (single-use)

AI/ML Overview

The provided document is a 510(k) premarket notification for the Zimmer Biomet X-PSI Knee System. It details the device, its indications for use, and a summary of performance data used to establish substantial equivalence to predicate devices.

Here's a breakdown of the requested information based on the provided text:

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

The document states that a non-significant risk clinical study was performed to evaluate the proper positioning of the Zimmer Biomet X-PSI Knee guides. The primary metric measured was the resulting frontal Hip-Knee-Ankle (HKA) alignment angle versus the surgically planned HKA alignment angle.

Acceptance Criteria	Reported Device Performance
Satisfactory performance per the intended use regarding the resulting frontal Hip-Knee-Ankle (HKA) alignment angle versus the surgically planned HKA alignment angle.	The results demonstrated satisfactory performance per the intended use.

Note: The document states "satisfactory performance" but does not provide specific numerical thresholds or a statistical comparison for the HKA alignment angle, which would typically be included in detailed acceptance criteria. It also mentions "substantial equivalence in cut accuracy with regards to femoral and tibial frontal and sagittal angles, as well as femoral rotation and resection depth" based on full system validation tests, but no specific acceptance criteria for these were detailed.

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

The document does not explicitly state the sample size for the clinical study (test set) or the data provenance (country of origin, retrospective/prospective). It only refers to it as a "Non-Significant Risk Clinical Study."

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)

The document does not provide details on the number of experts or their qualifications for establishing the ground truth in the clinical study.

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

The document does not describe any adjudication method used for the clinical study's test set.

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

The document does not mention a multi-reader multi-case (MRMC) comparative effectiveness study or any assessment of human reader improvement with AI assistance. The device is an orthopedic instrument system that assists in surgical planning and guiding, not a diagnostic AI tool that human readers would interpret.

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

The document describes "Software System Tests" which were performed to "ensure that no hazardous anomalies were present in the system software components" and "consisted of testing software features and functionalities in correspondence to software design requirements." This implies a standalone evaluation of the software's functional performance, but not in terms of diagnostic accuracy or clinical outcomes in isolation. The "Full System Validation Tests" using cadaver specimens and bone models involved "multiple surgeons," indicating a human-in-the-loop component for these tests, rather than purely standalone algorithm performance on clinical metrics.

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

For the clinical study, the ground truth was implied by surgically planned HKA alignment angle against which the "resulting frontal Hip-Knee-Ankle (HKA) alignment angle" was compared. This implies the surgical plan served as the reference for evaluating positioning accuracy. For the "Full System Validation Tests," the ground truth for "cut accuracy" (femoral/tibial angles, rotation, resection depth) would typically be established by precise measurements from the bone models or cadaver specimens, likely compared against the planned surgical cuts.

8. The sample size for the training set

The document does not specify a sample size for the training set for the software or any AI/ML components. It mentions that the software "sequentially construct[s] 3-D surface models of each patient's knee joint bony structures and articular surfaces from the patient's X-Ray images," but it doesn't detail how this software was trained or validated in terms of data volume.

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

The document does not provide information on how the ground truth for any potential training set was established.

Summary

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December 28, 2017

Orthosoft Inc. (d/b/a Zimmer CAS) Paul Hardy Senior Specialist, Regulatory Affairs 75 Queen Street. Suite 3300 Montreal, H3C 2N6 Canada

Re: K171269

Trade/Device Name: X-PSI Knee 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, MBH, LLZ Dated: November 17, 2017 Received: November 20, 2017

Dear Paul Hardy:

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

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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.

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 mediation-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) K171269

Device Name X-PSI Knee System

Indications for Use (Describe)

The patient specific guide components are intended for single-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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In accordance with 21 CFR §807.92 and the Safe Medical Devices Act of 1990, the following information is provided for the Zimmer Biomet • X-PSI Knee System 510(k) premarket notification. The submission was prepared in accordance with the FDA guidance document, 'Format for Traditional and Abbreviated 510(k)'s, issued on August 12, 2005.

Sponsor:	Orthosoft, Inc. d/b/a Zimmer CAS75 Queen St., Suite 3300Montreal, Quebec, CANADA H3C 2N6Establishment Registration Number: 9617840
Contact Person:	Paul HardyZimmer Biomet574-372-6799
Date:	December 27, 2017
Subject Device:	Trade Name: Zimmer Biomet® X-PSI Knee SystemCommon Name: Surgical Knee Guide
Product Codes:	OOG, JWH, MBH, LLZ

Classification Name:

. Knee Joint Patello/Femorotibial Polymer/Metal/Polymer Semi-Constrained Cemented Prosthesis / 21 CFR § 888.3560 / Product Code JWH
. Knee Joint Patello/Femorotibial Polymer/Metal/Polymer Semi-Constrained Cemented Prosthesis / 21 CFR § 888.3560 / Product Code OOG
Prosthesis. Knee, Patello/Femorotibial. Semi-Constrained, uncemented. Porous. Coated, Polymer/Metal / MBI-, Knee Joint Patello/Femorotibial Metal/Polymer Porous-Coated Uncemented Prosthesis / 21 CFR § 888.3565/ Product Code MBH
Picture Archiving and Communications System/ 21 CFR § 892.2050 / Product Code LLZ

Predicate Device(s):

Manufacturer	Device	510(k)Number	Type
Zimmer CAS	CAS PSIKnee System	K131409	Predicate
ONEFITMedical	Knee EOS	K161828	Reference

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Device Description:

It involves the following:

A CAS X-PSI Knee Software Suite used in preparation for the surgery to sequentially construct 3-D surface models of each patient's knee joint bony structures and articular surfaces from the patient's X-Ray images, plan the location and orientation of the knee replacement implant components upon the patient's model, and create the corresponding specification models for the patient specific surgical guides (PSI Guides) with surfaces and elements to uniquely fit each patient topographical features and set or reference the placement of the implant system components per the plan,
. The Zimmer Biomet ® X-PSI Guides (also called jigs) that are manufactured per the above models and plan, for intra-operative and single use, which include one to set the placement of the distal femoral cut guides which set the resection depth, the varus/valgus and the flexion of the distal cut and one to set the placement of the tibial cut guides which set the resection depth, the varus/valgus, and the posterior slope of the proximal cut.
. Each patient's Zimmer Biomet ®3-D Bone Models (femur and tibia components) that are fabricated and provided along with the PSI Guides for use intra-operatively to provide the surgeon with an intra-operative visual reference of the planned location of the PSI Guides in order to help guide their locations on the patient's actual joint,
Zimmer Biomet X-PSI Reusable Surgical Instrumentations are provided both sterile . and non-sterile and are reusable for intra-operative use, which include femoral stylus, and femoral and tibial cut block instrumentations to allow setting the resection level and performing the bone cuts as defined by the PSI Guides.
Fixation Pins are accessories for use of the guides, these accessories are Class I devices under the classification "Orthopedic manual surgical instrument (21 CFR § 888.4540)".

The Zimmer Biomet® X-PSI Knee System is compatible for use with the following class II Zimmer Biomet Nexgen, Persona and Vanguard total knee replacement implant systems:

. NexGen®family: NexGen CR, NexGen CR-Flex, NexGen CR-Flex Gender, NexGen LPS, NexGen LPS-Flex, NexGen LPS-Flex Gender
. Persona® family: Persona CR, Persona PS
Vanguard® family: Vanguard CR, Vanguard PS

Finally, the following accessories are used for the acquisition of the x-ray images:

X-Ray Marker 3D Zimmer Biomet ® X-PSI (re-usable) ●
X-Ray Calibration Straps, Short and Long (single-use)

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These accessories are class I device under the classifications "Radiologic quality assurance instrument (21 CFR § 892.1940)" and "Radiographic film marking system (21 CFR § 892.1640)".

Indications for Use:

The Zimmer Biomet® X-PSI Knee System is indicated as an orthopedic instrument system to assist in the positioning of knee replacement components. It involves surgical planning software used pre-operatively to plan the surgical placement of the components on the basis of provided patient radiological images and 3-D reconstructed bones with identifiable placement anatomical landmarks, and surgical instrument components that include patient specific or customized guides fabricated on the basis of the surgical plan to precisely reference the placement of the implant components intra-operatively per the surgical plan. The X-PSI Knee system is indicated for patients without severe bone deformities, such as a HKA greater than 15° or deformities due to prior fracture of the distal femur or proximal tibia.

The Zimmer Biomet® X-PSI Knee System is to be used with the following fixed bearing knee replacement systems in accordance with their indications and contraindications: NexGen® CR, NexGen CR-Flex, NexGen CR-Flex Gender, NexGen LPS, NexGen LPS-Flex, NexGen LPSFlex Gender, Persona® CR, Persona PS, Vanguard® CR and Vanguard PS.

The patient specific guide components are intended for single-use only.

Summary of Technological Characteristics:

While the CAS PSI Knee System uses MRI DICOM as an input, the Zimmer Biomet® XPSI ● Knee System utilizes x-ray DICOM as an input as does the Knee EOS System.
. Both the CAS PSI Knee System and the Zimmer Biomet • X-PSI Knee System utilize the same software suites for triage, reconstruction, landmark acquisition, planning, guide creation, and bone model creation.
. The Guides are substantially equivalent, however the Zimmer Biomet®X-PSI Knee System guides utilize a different method for attachment to the knee joint than that used in the CAS PSI Knee System.
The guides and bone models are manufactured using a 3-D printing method, Selective Laser Sintering (SLS).

Summary of Performance Data:

(Nonclinical and/or Clinical)

Four different types of non-clinical and/or clinical tests were conducted to verify and validate the performance of the system and assess that no new safety and efficacy issues were raised in the device.

Software System Tests: They were performed to ensure that no hazardous anomalies were present in the system software components. They consisted of testing software features and functionalities in correspondence to software design requirements.
Guide Mechanical Resistance Tests: Tests were performed to verify the mechanical .

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performance of the guides including resistance to use or drop breakage, debris generation, aging stability, sterilization, and extreme shipping conditions.

. Full System Validation Tests: Full use simulations tests using cadaver specimens and/or bone models were performed by multiple surgeons in multiple settings to verify and validate the overall system performance in terms of system usage and instrument ergonomics. The results demonstrated that the X-PSI Knee System is substantially equivalent in cut accuracy with regards to femoral and tibial frontal and sagittal angles, as well as femoral rotation and resection depth.
Non-Significant Risk Clinical Study: A clinical study was performed to evaluate ● proper positioning of the Zimmer Biomet® X-PSI Knee guides. This study measured the resulting frontal Hip-Knee-Ankle (HKA) alignment angle versus the surgically planned HKA alignment angle. The results demonstrated satisfactory performance per the intended use.

Substantial Equivalence Conclusion:

In summary, the proposed Zimmer Biomet® X-PSI Knee System is substantially equivalent to the CAS PSI Knee System predicate, as well as the kneeEOS reference in regards to X-Ray imaging and reconstruction with the same intended use and similar technology. Design verification and validation tests, including performance and clinical tests, demonstrated the substantial equivalence of the system.

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.