(116 days)
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.
"UNITED" U2 Total Knee System - Posterior Stabilized Augmentable (PSA) type is an extended design of "UNITED" U2 Total Knee system. It is a Patellofemorotibia, polymer/metal/polymer, semi-constrained, cemented knee prosthesis, which has a cobalt-chromium-molybenum (Co-Cr-Mo) alloy femoral component and a tibial component composed of a polyethylene insert machined from compressed molded UHMWPE and a Ti-6Al-4V metallic tibial baseplate. This system is intended for use in patients who require augmentation and/or stem extensions due to inadequate bone stock. There are a variety of components including femoral augment set, tibial augment, stem extension and offset stem adapter that provides more choices for surgeon to treat their patients. In addition, this system also provides more constraint of tibiofemoral joint when patients require more constrained stabilization due to inadequate mediolateral. anterioposterior or varus-valgus soft tissue imbalance. The components of U2 Total Knee system-PSA Type are listed as below.
The provided text describes a 510(k) summary for the U2 Total Knee System - PSA Type, a medical device. This type of submission focuses on demonstrating "substantial equivalence" to a legally marketed predicate device, rather than proving efficacy through clinical trials with defined acceptance criteria for device performance as would be seen in novel devices.
Therefore, the document does not contain the following information typically associated with complex AI/ML device studies:
- Acceptance Criteria and Reported Device Performance Table: The submission focuses on substantial equivalence to existing devices through a series of bench tests. It doesn't report performance against specific, quantifiable acceptance criteria in terms of accuracy, sensitivity, specificity, etc., that would be expected for a diagnostic or predictive AI/ML device.
- Sample sized used for the test set and the data provenance: Not applicable as it's not a clinical study on patient data.
- Number of experts used to establish the ground truth for the test set and the qualifications of those experts: Not applicable.
- Adjudication method: Not applicable.
- Multi reader multi case (MRMC) comparative effectiveness study: Not applicable.
- Standalone (i.e. algorithm only without human-in-the-loop performance) study: Not applicable.
- Type of ground truth used: Not applicable.
- Sample size for the training set: Not applicable.
- How the ground truth for the training set was established: Not applicable.
What the document does provide regarding "performance" and "acceptance criteria" through the lens of substantial equivalence:
The "acceptance criteria" here are implicitly tied to demonstrating that the new device performs "as well or better than the predicate devices in all areas tested" (Page 1) and meets ASTM standards for materials. The "study" is a series of bench tests designed to show this equivalence.
Here's the relevant information that can be extracted:
1. Table of Acceptance Criteria and Reported Device Performance:
| Test Performed | Implicit Acceptance Criteria | Reported Device Performance |
|---|---|---|
| 1. Tibiofemoral Range of Motion | Performance "as well or better" than predicate devices (specifications likely derived from predicate device performance). | Test data indicates performance "as well or better than the predicate devices". |
| 2. Finite Element Analysis of Tibial Tray | Performance "as well or better" than predicate devices (likely assessing stress distribution, stability). | Test data indicates performance "as well or better than the predicate devices". |
| 3. Constraints of the Tibiofemoral Joint | Performance "as well or better" than predicate devices (specifically for stability). | Test data indicates performance "as well or better than the predicate devices". |
| 4. Contact Area and Contact Pressure in Tibiofemoral Joint | Performance "as well or better" than predicate devices (implying optimized load distribution). | Test data indicates performance "as well or better than the predicate devices". |
| 5. Articulating Surface Finish of Femoral Component and Tibial Insert | Performance "as well or better" than predicate devices (implying acceptable wear characteristics and reduced friction). | Test data indicates performance "as well or better than the predicate devices". |
| 6. Locking Strength of Tibial Component | Performance "as well or better" than predicate devices (ensuring secure assembly). | Test data indicates performance "as well or better than the predicate devices". |
| 7. Fatigue Test for Metal Tibial Baseplate | Performance "as well or better" than predicate devices, and meeting relevant ASTM material standards. | Test data indicates performance "as well or better than the predicate devices". Materials meet ASTM standards. |
| 8. Fatigue Test for Tibial Insert Spine | Performance "as well or better" than predicate devices, and meeting relevant ASTM material standards. | Test data indicates performance "as well or better than the predicate devices". Materials meet ASTM standards. |
| Material Properties (Co-Cr-Mo alloy, UHMWPE, Ti-6Al-4V) | Meet the property requirements of the ASTM standards associated with each material. | Materials used in manufacture meet the property requirements of the ASTM standards associated with each material. |
2. Sample size used for the test set and the data provenance:
- This was a bench study, not a clinical study involving patient data. Therefore, the concept of "sample size for the test set" in the context of patient data provenance (country of origin, retrospective/prospective) is not applicable. The sample sizes would refer to the number of device components tested in each bench test, but this detail is not provided in the summary.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Not applicable as this is a bench study on a medical device, not an AI/ML diagnostic interpretation where expert ground truth is established.
4. Adjudication method:
- Not applicable.
5. Multi reader multi case (MRMC) comparative effectiveness study:
- No, this was not done. This type of study is typical for diagnostic AI devices comparing human readers with and without AI assistance, which is not the nature of this device or its submission.
6. Standalone (i.e. algorithm only without human-in-the-loop performance) study:
- Not applicable, as this is a mechanical knee implant, not an algorithm.
7. The type of ground truth used:
- For the bench tests, the "ground truth" would be the established engineering specifications, material standards (ASTM), and the performance characteristics of the predicate devices.
8. The sample size for the training set:
- Not applicable as this is not an AI/ML device requiring a training set.
9. How the ground truth for the training set was established:
- Not applicable.
§ 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.