The U2 Total Knee system is indicated in knee arthroplasty for reduction or relief of pain and/or improved knee function in skeletally mature patients with severe knee pain and disability due to rheumatoid arthritis, osteoarthritis, primary and secondary traumatic arthritis, polyarthritis, collagen disorders, avascular necrosis of the femoral condyle or pseudogout, posttraumatic loss of joint configuration, particularly when there is patellofemoral erosion, dysfunction or prior patellectomy, moderate valgus, varus, or flexion deformities. This device may also be indicated in the salvage of previously failed surgical attempts if the knee can be satisfactorily balanced and stabilized at the time of surgery. This device is a single use implant and intended for cemented use only.

Device Description

This subjected device includes femoral component, tibial insert, XPE tibial insert and ultracongruent insert. It is a size extension to the cleared "UNITED" U2 Total Knee System (K051640, K120507, K131864, K103733, K132752, and K140073). The indications, materials, design of this subject device are identical to the cleared "UNITED" U2 Total Knee System except for its dimension.

AI/ML Overview

The provided text is a 510(k) summary for the U2 Total Knee System-Additional Sizes. This document outlines the regulatory filing for a medical device and typically focuses on demonstrating substantial equivalence to a predicate device, rather than presenting a detailed study proving the device meets specific performance acceptance criteria in terms of AI/software performance.

Therefore, many of the requested categories related to AI/software performance, such as sample size for test sets, expert ground truth, adjudication methods, MRMC studies, standalone performance, and training set details, are not applicable to this type of regulatory submission for a physical knee implant.

However, I can extract information related to the device's non-clinical performance and its comparison to a predicate device, as that is the focus of this document.

Here's the breakdown of the information that can be extracted, and where applicable, a note on why certain information is not present:

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

The document does not explicitly state quantitative "acceptance criteria" for the non-clinical tests in the usual sense of a specific pass/fail threshold with reported numerical performance values against those thresholds. Instead, it states that the tests "demonstrated that this device is safe and effective." The demonstration of safety and effectiveness relies on the device having the "same basic design, intended use, materials and the same manufacturing method" as predicate devices, with the only difference being "dimension." The non-clinical tests listed below were performed to confirm performance characteristics.

Test Performed	Reported Device Performance
Range of Motion	"demonstrated that this device is safe and effective"
Contact Area and Contact Pressure on Femorotibial Joint	"demonstrated that this device is safe and effective"
Contact Area and Contact Pressure on Femoropatellar Joint	"demonstrated that this device is safe and effective"
Constraint of Femorotibial Joint	"demonstrated that this device is safe and effective"
Fatigue Compression Test of Femoral Component	"demonstrated that this device is safe and effective"
Locking Strength of Tibial Insert	"demonstrated that this device is safe and effective"
Fatigue Performance of Tibial Insert Spine	"demonstrated that this device is safe and effective"
Materials Properties of U2 XPE Tibial Insert	"demonstrated that this device is safe and effective"

Note: The document confirms these tests were conducted "in accordance with the Agency's, 'Class II Special Controls Guidance Document: Knee Joint Patellofemorotibial and Femorotibial Metal/Polymer Porous-Coated Uncemented Prostheses; Guidance for Industry and FDA'." This implies that the tests were designed and evaluated against established industry and regulatory standards, which serve as the implicit "acceptance criteria." However, the exact numerical criteria and specific results are not detailed in this summary.

2. Sample sizes used for the test set and the data provenance: Not applicable. This document describes physical device testing, not AI/software performance evaluation with a "test set" in the computational sense. The "tests" refer to laboratory-based mechanical and materials evaluations.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts: Not applicable. No "ground truth" establishment by experts in the context of image analysis or diagnostic AI is mentioned. Evaluations are based on engineering principles and test results.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set: Not applicable.

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 applicable. This is a physical prosthetic device, not an AI software.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done: Not applicable.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc): Not applicable in the context of conventional AI/software ground truth. The "truth" for this device lies in its compliance with engineering standards, material properties, and mechanical performance under simulated physiological conditions, benchmarked against predicate devices.

8. The sample size for the training set: Not applicable. This is not an AI/machine learning device.

9. How the ground truth for the training set was established: Not applicable.

Summary of the Study that Proves the Device Meets Acceptance Criteria (as described in the document):

The "study" refers to a series of non-clinical performance tests conducted on the U2 Total Knee System-Additional Sizes. The summary states these tests were performed "in accordance with the Agency's, 'Class II Special Controls Guidance Document: Knee Joint Patellofemorotibial and Femorotibial Metal/Polymer Porous-Coated Uncemented Prostheses; Guidance for Industry and FDA'".

The key premise for demonstrating safety and effectiveness and meeting acceptance criteria, as per this 510(k) summary, is substantial equivalence to several predicate devices (e.g., "UNITED" U2 Total Knee System K051640). The document explicitly states:

"U2 Total Knee System, Additional Sizes has the same basic design, intended use, materials and the same manufacturing method as device of the 'United' U2 Total Knee System..."
"The only difference between the cleared and subjected device is dimension."

The non-clinical tests listed above (Range of Motion, Contact Area and Pressure, Constraint, Fatigue Compression, Locking Strength, Fatigue Performance of Insert Spine, Material Properties) were performed to confirm that, despite the dimensional differences, the additional sizes maintain the same performance characteristics as the predicate devices, thereby ensuring safety and effectiveness. The conclusion provided is that "the test results demonstrated that this device is safe and effective."

Clinical Performance Data:
The document explicitly states: "None provided as a basis for substantial equivalence." This reinforces that the substantial equivalence determination for this submission relies entirely on non-clinical data and comparison to predicate devices, rather than new clinical trials for the specific additional sizes.

Summary

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Image /page/0/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo features the department's name in a circular arrangement around a symbol. The symbol depicts a stylized representation of three human profiles facing to the right, stacked on top of each other. The profiles are rendered in a dark color, contrasting with the white background.

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

September 25, 2015

United Orthopedic Corporation Fang-Yuan Ho Regulatory Affairs Manager Number 57, Park Avenue 2, Science Park Hsinchu 300 Taiwan

Re: K150829 Trade/Device Name: U2 Total Knee System-Additional Sizes Regulation Number: 21 CFR 888.3650 Regulation Name: Knee joint patellofemorobial polymer/metal semi-constrained cemented prosthesis Regulatory Class: Class II Product Code: JWH Dated: March 20, 2015 Received: March 30, 2015

Dear Fang-Yuan Ho:

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 (reporting of medical

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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.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Division of Industry and Consumer Education 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. 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 Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.

Sincerely yours,

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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Indication for Use

510 (k) Number (if known):

Device Name: U2 Total Knee System-Additional Sizes

Indications for Use:

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

Concurrence of CDRH, Office of Device Evaluation (ODE)

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೪ U2 Total Knee System—Additional Sizes

510(k) Summary of Safety and Effectiveness

Submitter Information

Name	United Orthopedic Corporation
Address	No 57, Park Ave 2, Science Park, Hsinchu 300, Taiwan
Phone Number	+886-3-5773351 ext. 2212
Fax Number	+886-3-577156
Name of Contact Person	Fang-Yuan HoRegulation and Document Management
Date prepared	March 20, 2015
Name of Device
Trade Name	U2 Total Knee System—Additional Sizes
Common Name	Total Knee Prosthesis
Classification Name andRegulation	Knee joint patellofemorotibial polymer/metal/polymersemi-constrained cemented prosthesis under 21CFR §888.3560
Device Class	Class II
Classification Panel	Orthopaedics
Product Code	JWH
Predicate Device	1. “UNITED” U2 Total Knee System (K051640)2. “UNITED” U2 XPE Total Knee System (K103733)3. “UNITED” U2 Femoral Component, PS, #7 (K120507)4. “UNITED” Tibial inserts, #7 (K131864)5. “UNITED” Ultracongruent Insert (K132752)6. “UNITED” U2 Femoral Component, CR, Cemented (K140073)

Device Description:

This subjected device includes femoral component, tibial insert, XPE tibial insert and

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0 U2 Total Knee System-Additional Sizes

510(k) Summary

ultracongruent insert. It is a size extension to the cleared "UNITED" U2 Total Knee System (K051640, K120507, K131864, K103733, K132752, and K140073). The indications, materials, design of this subject device are identical to the cleared "UNITED" U2 Total Knee System except for its dimension.

Intended Use:

Comparison to Predicate Device:

U2 Total Knee System, Additional Sizes has the same basic design, intended use, materials and the same manufacturing method as device of the "United" U2 Total Knee System (K051640, K120507, K131864, K103733, K132752 and K140073). The only difference between the cleared and subjected device is dimension.

Performance Data:

● Non-clinical Performance

This 510(k) submission was prepared in accordance with the Agency's, " Class II Special Controls Guidance Document: Knee Joint Patellofemorotibial and Femorotibial Metal/Polymer Porous-Coated Uncemented Prostheses; Guidance for Industry and FDA". Tests as follows were conducted to evaluate the safety and effectiveness of the subjected device, and the test results demonstrated that this device is safe and effective.

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g U2 Total Knee System—Additional Sizes

Range of Motion a.
Contact Area and Contact Pressure on Femorotibial Joint b.
Contact Area and Contact Pressure on Femoropatellar Joint c.
Constraint of Femoroltibial Joint d.
Fatigue Compression Test of Femoral Component e.
Locking Strength of Tibial Insert f.
Fatigue Performance of Tibial Insert Spine g.
Materials Properties of U2 XPE Tibial Insert h.

● Clinical Performance Data/Information

None provided as a basis for substantial equivalence.

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.