The Evolis®/GMK® knee prosthesis is designed for cemented use in total knee arthroplasty, if there is evidence of sufficient sound bone to seat and support the components.

This knee replacement system is indicated in the following cases:

· Severely painful and/or disabled joint as a result of arthritis, traumatoid arthritis, theumatoid arthritis.
· Avascular necrosis of femoral condyle.
· Post traumatic loss of joint configuration.
· Primary implantation failure.

GMK Sphere can be implanted using a kinematic alignment approach. When a kinematic alignment approach is utilized, this knee replacement system is indicated in the following cases:

· Severely painful and/or disabled joint as a result of arthritis, traumatoid arthritis or polyarthritis.
· Collagen disorders, and/or avascular necrosis of the femoral condyle.
· Moderate valgus, varus, or flexion deformities.

Tibial wedges cemented are to be attached to the tibial baseplate with both the fixing cylinders and bone cement. The screwed tibial augments are for screwed fixation to the tibial baseplate.

In case a semi-constrained liner is used, an extension stem must be implanted both on the femoral components.

In case a GMK Revision tibial tray is used, an extension stem must be implanted.

Device Description

The purpose of this submission is to gain clearance for the GMK Sphere – Kinematic Alignment surgical technique and the technique specific instruments. The proposed kinematic alignment technique is an alternative alignment strategy to the traditional mechanical alignment used for total knee arthroplasty. The purpose of the kinematic alignment technique is to restore normal knee function by aligning the distal and posterior femoral joint lines of the tibial component to those of the normal or pre-arthritic state.

The GMK Sphere - Kinematic Alignment surgical technique will be used with the following components of the GMK Sphere System cleared under K121416, K140826, and K162035:

o Tibial Insert Fixed Flex: Left and Right, Sizes 1 - 6, 10 - 20 mm (including intermediate sizes 11 mm and 12 mm), UHMWPE Type 1, Fixation Screw: Ti6Al4V;
Femoral Component Left and Right, Sizes 1 7, Co-Cr-Mo; ●
Femoral Component Left and Right, Sizes 1+ 6+ (intermediate sizes), Co-Cr-Mo; ●
Tibial Tray Fixed Cemented Left and Right, 4 intermediate sizes, Co-Cr-Mo; ●
o Tibial Insert Fixed Flex, Left and Right, Sizes 1 - 6, 10 mm - 20 mm, UHMWPE Type 1, Ti6Al4V:
o Tibial Insert Fixed Flex, Left and Right, Sizes 1 - 6, 11 mm and 13 mm, UHMWPE Type 1. Ti6Al4V: and
instrumentation. ●

AI/ML Overview

This document is a 510(k) premarket notification for the "GMK Sphere - Kinematic Alignment" knee replacement system. It primarily focuses on demonstrating substantial equivalence to previously cleared predicate devices, particularly concerning the introduction of a new kinematic alignment surgical technique and associated instruments.

Based on the provided text, the device itself is a "Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis." The study described is a demonstration of substantial equivalence rather than a study proving the device meets clinical acceptance criteria through, for example, a clinical trial or a study assessing AI performance.

Therefore, the information requested in the prompt, especially concerning AI performance metrics, expert roles, and multi-reader multi-case studies, is not applicable to the content of this 510(k) submission.

However, I can extract information related to the engineering and mechanical performance testing of the device, which aligns with device acceptance criteria for a physical medical device.

Here's an interpretation based on the provided document:

Study Type: This is a 510(k) Premarket Notification, which aims to demonstrate substantial equivalence to legally marketed predicate devices, not specifically to prove AI performance or the effect of AI assistance on human readers. The "study" described is a series of non-clinical, benchtop and cadaveric performance tests to ensure the new surgical technique and instruments maintain the safety and effectiveness of the existing GMK Sphere system.

1. Table of Acceptance Criteria and Reported Device Performance:

The document mentions that "verification activities, as identified through risk analysis, were conducted to written protocols with pre-defined acceptance criteria." However, the specific numerical acceptance criteria and the detailed reported performance values are not provided in this summary document. Only the types of tests performed are listed.

Acceptance Criterion (Type of Test)	Reported Device Performance (Summary from document)
Mechanical resistance of the femoral component under physiological static and dynamic loads	Demonstrated to support substantial equivalence. (Implied: met pre-defined acceptance criteria, but specific values not reported in this summary).
Wear behavior	Demonstrated to support substantial equivalence. (Implied: met pre-defined acceptance criteria, but specific values not reported in this summary).
Range of motion (ROM)	Tested for both predicate and subject devices. (Implied: results were consistent with predicate, met pre-defined acceptance criteria, but specific values not reported in this summary).
Mechanical resistance of the tibial tray under physiological static and dynamic loads	Demonstrated to support substantial equivalence. (Implied: met pre-defined acceptance criteria, but specific values not reported in this summary).
Sterilization validation	Demonstrated to support substantial equivalence. (Implied: met pre-defined acceptance criteria, but specific values not reported in this summary).
Shelf life	Demonstrated to support substantial equivalence. (Implied: met pre-defined acceptance criteria, but specific values not reported in this summary).
Pyrogenicity	Demonstrated to support substantial equivalence. (Implied: met pre-defined acceptance criteria, but specific values not reported in this summary).
Expected Loads	Tested for subject devices. (Implied: met pre-defined acceptance criteria, but specific values not reported in this summary).
Level of Constraints	Tested for subject devices. (Implied: met pre-defined acceptance criteria, but specific values not reported in this summary).
Primary and Secondary Fixation	Tested for subject devices. (Implied: met pre-defined acceptance criteria, but specific values not reported in this summary).
Cadaveric workshop for validation of the surgical technique and the relative dedicated instruments set	Conducted. (Implied: validated the technique and instruments).

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

Sample Size: The document does not specify the numerical sample sizes for the various mechanical and cadaveric tests (e.g., number of components tested, number of cadavers used). It refers to "verification activities... conducted to written protocols."
Data Provenance: The tests are described as non-clinical (benchtop) and cadaveric, meaning they are laboratory or ex-vivo studies. The document does not provide information about the country of origin of the data beyond implicitly being part of Medacta's internal R&D process (Medacta International SA is based in Switzerland). The data is prospective in the sense that these tests were conducted specifically for this submission.

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

This concept, as it relates to expert review of medical images for ground truth, is not applicable to this type of device and submission. The "ground truth" for mechanical and cadaveric tests would be established by the physical and engineering properties of the materials and the biomechanical behavior observed, measured against engineering standards and specifications. There's no mention of interpreting visual data by human experts for this purpose.

4. Adjudication Method for the Test Set:

Not applicable in the context of expert consensus for imaging or clinical outcomes. Test results are likely adjudicated against pre-defined engineering specifications and standards, not through a human consensus process.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done:

No. This type of study (MRMC) is relevant for AI-powered diagnostic devices where human readers interpret medical images. This 510(k) is for a physical knee implant and surgical technique, not an AI product assisting in diagnosis.

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

No. This concept applies to AI algorithms. The "device" here is a physical implant and surgical instruments.

7. The Type of Ground Truth Used:

The "ground truth" for these tests are:

Engineering Specifications/Standards: Performance measured against established industry standards and internal design specifications for mechanical properties (e.g., strength, wear, range of motion).
Biomechanical Principles: For cadaveric studies, the "ground truth" is the observed anatomical and biomechanical response of the tissues and device under simulated physiological conditions.

8. The Sample Size for the Training Set:

Not applicable. There is no "training set" in the context of an AI algorithm described here. The development of the device (implant and technique) is based on engineering design, material science, and prior surgical experience, not machine learning from a dataset.

9. How the Ground Truth for the Training Set was Established:

Not applicable. As there is no training set for an AI algorithm, this question is not relevant to the provided document.

Summary

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Image /page/0/Picture/0 description: The image contains two logos. On the left is the Department of Health & Human Services logo, which features a stylized human figure. To the right of that is the FDA logo, which is a blue square with the letters "FDA" in white, followed by the words "U.S. FOOD & DRUG ADMINISTRATION" in blue.

August 23, 2018

Medacta International SA % Elizabeth Rose Manager, Regulatory Affairs Mapi USA, Inc. 2343 Alexandria Drive, Suite 100 Lexington, Kentucky 40504

Re: K173890

Trade/Device Name: GMK Sphere - Kinematic Alignment Regulation Number: 21 CFR 888.3560 Regulation Name: Knee Joint Patellofemorotibial Polymer Semi-Constrained Cemented Prosthesis Regulatory Class: Class II Product Code: JWH Dated: December 21, 2017 Received: December 21, 2017

Dear Elizabeth Rose:

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/cfpmp/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.

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

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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/CombinationProducts/GuidanceRegulatoryInformation/ucm597488.htm); 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 http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm.

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.

Image /page/1/Picture/6 description: The image shows a digital signature. The signature is by Vesa Vuniqi - S. The date of the signature is 2018.08.23. The time of the signature is 17:12:07 -04'00'.

Mark N. Melkerson For: 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)

K173890

Device Name GMK Sphere - Kinematic Alignment

Indications for Use (Describe)

The Evolis®/GMK® knee prosthesis is designed for cemented use in total knee arthroplasty, if there is evidence of sufficient sound bone to seat and support the components.

This knee replacement system is indicated in the following cases:

· Severely painful and/or disabled joint as a result of arthritis, traumatoid arthritis, theumatoid arthritis.
· Avascular necrosis of femoral condyle.
· Post traumatic loss of joint configuration.
· Primary implantation failure.

GMK Sphere can be implanted using a kinematic alignment approach. When a kinematic alignment approach is utilized, this knee replacement system is indicated in the following cases:

· Severely painful and/or disabled joint as a result of arthritis, traumatoid arthritis or polyarthritis.
· Collagen disorders, and/or avascular necrosis of the femoral condyle.
· Moderate valgus, varus, or flexion deformities.

Tibial wedges cemented are to be attached to the tibial baseplate with both the fixing cylinders and bone cement. The screwed tibial augments are for screwed fixation to the tibial baseplate.

In case a semi-constrained liner is used, an extension stem must be implanted both on the femoral components.

In case a GMK Revision tibial tray is used, an extension stem must be implanted.

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

I. Submitter

Medacta International SA Strada Regina 6874 Castel San Pietro (CH) Switzerland Phone (+41) 91 696 60 60 Fax (+41) 91 696 60 66

Contact Person: Stefano Baj, Regulatory Affairs Manager Date Prepared: December 21, 2017 Date Revised: July 3, 2018

II. Device

Device Proprietary Name:	GMK Sphere – Kinematic Alignment
Common or Usual Name:	Total Knee Prosthesis
Classification Name:	Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis

Primary Product Code:	JWH
Regulation Number:	21 CFR 888.3560
Device Classification	2

III. Predicate Device

Substantial equivalence is claimed to the following predicate devices:

GMK Sphere, K121416, Medacta International SA
GMK Sphere Extension, K140826, Medacta International SA ●
GMK Sphere, K162035, Medacta International SA

Additional Predicate Devices:

Zimmer Persona Personalized Knee System, K172524, Zimmer, Inc.

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IV. Device Description

The GMK Sphere - Kinematic Alignment surgical technique will be used with the following components of the GMK Sphere System cleared under K121416, K140826, and K162035:

o Tibial Insert Fixed Flex: Left and Right, Sizes 1 - 6, 10 - 20 mm (including intermediate sizes 11 mm and 12 mm), UHMWPE Type 1, Fixation Screw: Ti6Al4V;
Femoral Component Left and Right, Sizes 1 7, Co-Cr-Mo; ●
Femoral Component Left and Right, Sizes 1+ 6+ (intermediate sizes), Co-Cr-Mo; ●
Tibial Tray Fixed Cemented Left and Right, 4 intermediate sizes, Co-Cr-Mo; ●
o Tibial Insert Fixed Flex, Left and Right, Sizes 1 - 6, 10 mm - 20 mm, UHMWPE Type 1, Ti6Al4V:
o Tibial Insert Fixed Flex, Left and Right, Sizes 1 - 6, 11 mm and 13 mm, UHMWPE Type 1. Ti6Al4V: and
instrumentation. ●

V. Indications for Use

The Evolis®/GMK® knee prosthesis is designed for cemented use in total knee arthroplasty, if there is evidence of sufficient sound bone to seat and support the components.

This knee replacement system is indicated in the following cases:

severely painful and/or disabled joint as a result of arthritis, traumatic arthritis, . rheumatoid arthritis or polyarthritis;
o avascular necrosis of femoral condyle;
post traumatic loss of joint configuration; and ●
primary implantation failure. ●

GMK Sphere can be implanted using a kinematic alignment approach. When a kinematic alignment approach is utilized, this knee replacement system is indicated in the following cases:

o severely painful and/or disabled joint as a result of arthritis, traumatic arthritis, rheumatoid arthritis or polyarthritis;
collagen disorders, and/or avascular necrosis of the femoral condyle; and ●
moderate valgus, varus, or flexion deformities. 0

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Tibial wedges cemented are to be attached to the tibial baseplate with both the fixing cylinders and bone cement.

The screwed tibial augments are for screwed fixation to the tibial baseplate.

In case a semi-constrained liner is used, an extension stem must be implanted both on the tibial and on the femoral components.

In case a GMK Revision tibial tray is used, an extension stem must be implanted.

VI. Comparison of Technological Characteristics

With the exception of the new instruments to be used with the kinematic alignment surgical technique, there are no differences in the fundamental scientific technology of the GMK Sphere - Kinematic Alignment. The safety and effectiveness of the surgical technique is adequately supported by the substantial equivalence information provided within this Premarket Notification.

The implants and instruments to be used with the GMK Sphere - Kinematic Alignment technique are exactly the same as the previously cleared GMK Sphere devices.

This submission introduces the kinematic alignment technique as an additional surgical technique for use with the GMK Sphere implants; this technique requires the use of more instrumentation than the previously cleared mechanical alignment surgical technique.

VII. Performance Data

As the subject devices are a line extension to the GMK Sphere family, verification activities, as identified through risk analysis, were conducted to written protocols with pre-defined acceptance criteria.

The following performance tests, conducted on the predicate devices, are being leveraged in support of this submission:

mechanical resistance of the femoral component under physiological static and dynamic ● loads;
wear behavior; ●
range of motion; ●
mechanical resistance of the tibial tray under physiological static and dynamic loads; ●
sterilization validation;
shelf life; and ●
pyrogenicity.

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Risks were identified based on the proposed surgical technique and testing was conducted to mitigate those risks. Based on the risk analysis, the following tests were conducted on the subject devices according to written protocols with acceptance criteria:

Non-Clinical Studies

Performance Tests
- range of motion (ROM); o
- expected loads; O
- level of constraints; O
- primary and secondary fixation; and o
- o cadaveric workshop for validation of the surgical technique and the relative dedicated instruments set.

Conclusion VIII.

Based on the above information, the GMK Sphere - Kinematic Alignment can be considered substantially equivalent to the identified predicate devices.

Substantial equivalence has been demonstrated through a comparison of intended use, design, and technological characteristics, as well as performance evaluations. The GMK Sphere -Kinematic Alignment is as safe and effective as the predicate devices.

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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.