This device 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 contraction. This device is intended for use in patients who require augmentation and/or stem extensions due to inadequate bone stock and/or require constrained stabilization for tibiofemoral joint due to soft tissue imbalance.

Device Description

"UNITED" U2 Total Knee System – PSA Type, Offset Stem Adapter is a modification of cleared Offset Stem Adapter (K082424). This device is manufactured from Ti-6AI-4V alloy (ASTM F136) and identical to the previously cleared offset stem adapter. The Offset Stem Adapter is intended for use in patients with inadequate bone stock. It allows the stem extension to be positioned away from the center of femoral or tibial component, and to center the stem extension within the bone medullar canal. There are three available offset sizes for the subjected device including 2, 4 and 6mm. It is able to be assembled with the femoral component, tibial baseplate and stem component utilizing Morse taper locking mechanism, and the Morse taper design is identical to our cleared Offset Stem Adapter (K082424). The modification does not affect the intended use of the device or alter the fundamental scientific technology of the device.

AI/ML Overview

The provided text describes a 510(k) premarket notification for a medical device, specifically the "U2 Total Knee System - PSA Type, Offset Stem Adapter." The documentation focuses on demonstrating substantial equivalence to predicate devices and includes a section on performance data.

Here's an analysis of the acceptance criteria and the study as described in the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

Acceptance Criteria	Reported Device Performance
Fatigue Strength Test Result	"this device is safe and effective."

2. Sample size used for the test set and the data provenance

The document does not specify the sample size used for the fatigue strength test. It also does not explicitly state the data provenance (e.g., country of origin, retrospective or prospective) for this test.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

Not applicable. This device is a mechanical implant, and its performance is evaluated through engineering tests (fatigue strength), not clinical studies requiring expert ground truth for interpretation of medical data.

4. Adjudication method for the test set

Not applicable, as the evaluation is based on a fatigue strength test rather than subjective interpretation requiring adjudication among experts.

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 document pertains to a mechanical knee implant, not an AI-powered diagnostic device.

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

Not applicable. This document pertains to a mechanical knee implant, not an algorithm.

7. The type of ground truth used

For the fatigue strength test, the "ground truth" would be the engineering standards and specifications against which the device's performance is measured. The document implies that the device met these standards, leading to the conclusion that it is "safe and effective."

8. The sample size for the training set

Not applicable. This document pertains to a mechanical knee implant, not a machine learning model that requires a training set.

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

Not applicable. As above, this is a mechanical device, not an AI system with a training set.

Summary of the Study:

The primary study mentioned to prove the device meets acceptance criteria is a fatigue strength test. This test was conducted to evaluate the structural integrity and durability of the Offset Stem Adapter. The report concludes that "the test result demonstrated that this device is safe and effective."

The basis for substantial equivalence is primarily focused on the device's similarity in intended use, raw material, design rationale, and sterilization method to previously cleared predicate devices (K082424, K093293, and K102437). This suggests that the fatigue strength test was likely performed to confirm that the modifications (specifically, the different offset sizes) did not negatively impact the mechanical performance compared to the predicate device.

Summary

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OCT 30 2013

510(k) Summary of Safety and Effectiveness

K131116

Submitted by:	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
Date of Summary:	April 17, 2013
Contact Person	Fang-Yuan HoRegulation and Document Management
Proprietary Name:	U2 Total Knee System - PSA Type, Offset Stem Adapter
Common Name:	Semi-constrained total knee prostheses
Device Classification	Knee joint patellofemorotibial polymer/metal/polymer
Name and Reference:	semi-constrained cemented prosthesis per 21CFR 888.3560.This falls under the Orthopedics panel.
Device Class	Class II
Panel Code	Orthopaedics Device
Device Product Code:	JWH
Predicate Device:	1. "UNITED" U2 Total Knee System – PSA Type (K082424)
	2. "BIOMET" Vanguard™ 360 Revision Knee System (K093293)
	3. "MEDACTA" GMK® Total Knee System- Revision

(K102437)

Device Description:

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K131116

extension to be positioned away from the center of femoral or tibial component, and to center the stem extension within the bone medullar canal.

There are three available offset sizes for the subjected device including 2, 4 and 6mm. It is able to be assembled with the femoral component, tibial baseplate and stem component utilizing Morse taper locking mechanism, and the Morse taper design is identical to our cleared Offset Stem Adapter (K082424). The modification does not affect the intended use of the device or alter the fundamental scientific technology of the device.

Indications:

Basis for Substantial Equivalence:

The intended use, raw material, design rationale and sterilization method of current submission device is substantially equivalent to legally marketed "UNITED" U2 Total Knee System - PSA Type (K082424), "BIOMET" VanguardTm 360 Revision Knee System (K093293) and "MEDACTA" GMK® Total Knee System- Revision (K102437).

Performance Data:

A fatigue strength test was conducted to evaluate the configuration strength of the Offset stem adapter, and the test result demonstrated that this device is safe and effective.

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Image /page/2/Picture/0 description: The image shows the logo for the U.S. Department of Health and Human Services. The logo consists of a stylized eagle with three stripes forming its body and wing. The eagle is positioned to the right of the text "DEPARTMENT OF HEALTH & HUMAN SERVICES USA", which is arranged in a circular fashion around the eagle.

DEPARTMENT OF HEALTH & HUMAN SERVICES

Public Health Service

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

October 30, 2013

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

Re: K131116

Trade/Device Name: U2 Total Knee System - PSA Type, Offset Stem Adapter Regulation Number: 888.3560 Regulation Name: Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis Regulatory Class: Class II Product Code: JWH Dated: September 30, 2013

Received: October 1, 2013

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. Ilsting 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

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Page 2 - Fang-Yuan Ho

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 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 Small Manufacturers, International and Consumer Assistance at its tollfree number (800) 638-2041 or (301) 796-7100 or at its Internet address

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

Sincerely vours.

Erin|阿弥eith

for

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

Enclosure

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K131116

Indication for Use

510 (k) Number (if known): K131116

Device Name: U2 Total Knee System- PSA Type, Offset Stem Adapter

Indications for Use:

Over-The-Counter Use Prescription Use AND/OR (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)

Casey L. Hanley, Ph.D.
Division of Orthopedic Devices

Page 1 of 1 Page: 6-1/1

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.