K Number
K222700
Date Cleared
2022-10-06

(29 days)

Product Code
Regulation Number
888.3560
Panel
OR
Reference & Predicate Devices
AI/MLSaMDIVD (In Vitro Diagnostic)TherapeuticDiagnosticis PCCP AuthorizedThirdpartyExpeditedreview
Intended Use

For Tibial baseplate, CMA, #0
This device is indicated in knee arthroplasty for reduction or relief of pain and/or improved knee function in sketetally mature patients with severe knee pain and disability due to rheumatoid arthritis, 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 joint surfaction or prior patellectorny, moderate valgus, varus, or flexion contraction. This device may also be indicated in the salvage or previously failed surgical attempts or for knee in which satisfactory stability in flexion cannot be obtained at the time of surgery. This device system is designed for cemented use only.

For Tibial insert, #0
The device is indicated in knee arthroplasty for reduction or relief of pain and/or improved knee function in sketally mature patients with severe knee pain and disability due to rheumatoid arthritis, 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

The U2 Total Knee System consists of Femoral components, patella components, Tibial baseplate components and Tibial inserts components which are designed to be used together to achieve total replacement of the knee joint. This system includes Cruciate Retained (CR) type, Ultracongruent (UC) type, and Posterior Stabilized (PS) type.

The U2 Total Knee System, Tibial baseplate, CMA, #0 (Subject device) is a size extension of the cleared "UNITED" U2 Total Knee System, Tibial baseplate, CMA, #1 to #7 (K131864). The materials, indications, sterilization of this subject are identical to the cleared "UNITED" U2 Total Knee System, Tibial baseplate, CMA, #1 to #7 (K131864).

The U2 Total Knee System, Tibial insert, #0 (Subject device) is a size extension of the cleared "UNITED" U2 Total Knee System, Tibial insert, #1 to #7 (K051640, K103733, K131864, K132752, K150829 and K161705). The materials, indications, sterilization of this subject are identical to the cleared "UNITED" U2 Total Knee System, Tibial insert, #1 to #7 (K051640, K103733, K131864, K132752, K150829 and K161705). The Subject Tibial insert, CR, #0 and Tibial insert, PS, #0 have a more concave sagittal plane design while comparing to the marketed predicate devices

Surgical procedures with the use of the Subject device shall be performed with the support of orthopedic instrumentation, to facilitate their proper insertion and removal from the patient. All the surgical instruments have been cleared as part of the predicate devices.

AI/ML Overview

This is a medical device clearance, not an AI/ML device. Therefore, the questions regarding AI/ML device evaluations (sample size, experts, adjudication, MRMC, standalone performance, ground truth establishment for training set, etc.) are not applicable.

The document describes the acceptance criteria and study for a Tibial baseplate and Tibial insert, which are components of a knee replacement system. This is a traditional medical device, not an AI/ML powered device. Therefore, the concepts related to AI/ML device performance such as ground truth, expert adjudication, train/test sets, effect size of AI assistance, etc., are not relevant to this document.

However, I can extract the information provided regarding the device's performance analysis and acceptance criteria, based on the non-clinical tests conducted.

Here's the summary of the acceptance criteria and the study that proves the device meets them, based on the provided text:

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

The document does not explicitly list 'acceptance criteria' with numerical targets and then 'reported device performance' side-by-side in a table format. Instead, it states that "the following non-clinical tests were conducted to evaluate the safety and effectiveness of the subjected device, and the test results indicated that this device is safe and effective." This implies that the device met the internal acceptance criteria for each test.

Acceptance Criteria Category (Implied)Reported Device Performance (Implied by Conclusion)
Range of MotionMet Safety and Effectiveness requirements
Locking Strength of Tibial baseplate and InsertMet Safety and Effectiveness requirements
Contact Area and Contact PressureMet Safety and Effectiveness requirements
Wear Simulation TestMet Safety and Effectiveness requirements
Fatigue Test of Tibial baseplateMet Safety and Effectiveness requirements
Spine Fatigue Test of Tibial insertMet Safety and Effectiveness requirements

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

The document does not specify the sample sizes (number of devices tested) for the non-clinical tests. It also does not provide information about data provenance as these are laboratory-based mechanical tests, not clinical data sets.

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)

Not applicable. This is a mechanical device, not an AI/ML device requiring expert ground truth for image interpretation or diagnosis.

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

Not applicable. This is a mechanical device. Adjudication methods are relevant for subjective interpretations, typically in clinical studies or AI/ML ground truth establishment.

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 mechanical device, not an AI/ML device.

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

Not applicable. This is a mechanical device, not an AI/ML device.

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

Not applicable. For mechanical devices, "ground truth" is typically defined by engineering specifications, material properties, and mechanical test standards (e.g., ISO or ASTM standards) that define acceptable performance limits. The document states that the "non-clinical tests were conducted to evaluate the safety and effectiveness," implying adherence to established engineering and material science principles, but specific ground truth definition is not explicitly detailed in this summary.

8. The sample size for the training set

Not applicable. This is a mechanical device, not an AI/ML device that requires a training set.

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

Not applicable. This is a mechanical device, not an AI/ML device.

§ 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.