(85 days)
The 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. Avascular necrosis of femoral condyle. Post traumatic loss of joint configuration. Primary implantation failure. Tibial augments are to be attached to the tibial baseplate with both the fixing cylinders and bone cement. In case a semi-constrained liner is used, an extension stem must be implanted both on the tibial and on the femoral components.
The GMK - Line Extension is comprised of the GMK Femur Size 7 and the GMK Revision extension stems. The 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.
The provided text describes a 510(k) premarket notification for a medical device, the GMK - Line Extension, which is a total knee prosthesis. The submission focuses on demonstrating substantial equivalence to predicate devices, primarily through mechanical performance testing.
Here's an analysis based on your requested information:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria Category | Specific Criteria/Standard | Reported Device Performance | Comments |
|---|---|---|---|
| GMK Femur Size 7 | The GMK Femur Size 7 was compared to the predicate GMK Femur Size 1 (identified as "worst case" by engineering analysis). | ||
| Volume for Cement Insertion | Adequacy to prevent loosening | Larger than worst case (Size 1) | Reduces risk of loosening of cement fixation. |
| Contact Surface Area | Adequacy to reduce contact stress | Larger than worst case (Size 1) | Reduces contact stress between tibial insert and femoral component. |
| Risk of Dislocation | Adequate level of constraint | Adequate, due to larger thickness and contact area | Adequate level of constraint to prevent dislocation. |
| Mechanical Strength | N/A (implied robustness) | Greater than worst case (Size 1) | Greater mechanical strength. |
| GMK Revision Extension Stems | Tested against applied standards and FDA guidance. | ||
| Endurance Property Testing | Applied standards per FDA guidance "Class II Special Controls Guidance Document: Knee Joint Patellofemorotibial and Femorotibial Metal/Polymer Porous-Coated Uncemented Prosthesis; Guidance for Industry and FDA", issued on Jan. 16, 2003. | Met all requirements | Demonstrated capability of withstanding expected in vivo loading without failure. |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: The document does not explicitly state a numerical sample size for individual tests. It refers to "testing on the worst case component size and option/design" for both the GMK Femur Size 7 and the GMK Revision extension stems. This suggests a limited sample size, focusing on representative "worst-case" scenarios rather than large statistical cohorts. For example, for the Femur Size 7, only Size 1 (worst case) was used for comparison.
- Data Provenance: The data is generated from mechanical performance testing conducted by the manufacturer, Medacta International, as part of their design verification process. It does not involve human patient data or clinical trials in the traditional sense. Therefore, the concepts of "country of origin of the data" or "retrospective/prospective" do not apply in the context of this mechanical performance testing.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
Not applicable. This submission relies on engineering analysis and adherence to established mechanical testing standards and FDA guidance documents to demonstrate substantial equivalence, not expert clinical consensus on a test set. The "ground truth" for this device's performance is determined by meeting the specified mechanical and performance standards.
4. Adjudication Method for the Test Set
Not applicable. There is no human test set or need for adjudication in this mechanical performance study.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No. An MRMC study is relevant for imaging or diagnostic devices where human readers interpret results. This submission is for a knee prosthesis, and the evaluation is based on mechanical performance and design equivalence, not human interpretation.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) Was Done
Not applicable. This is a physical medical device, not an algorithm or AI system.
7. The Type of Ground Truth Used
The "ground truth" for this device's safety and effectiveness (in the context of this 510(k)) is established through:
- Comparison to predicate devices with a history of safe and effective use.
- Adherence to recognized consensus standards and FDA guidance documents for mechanical testing of knee prostheses.
- Engineering analysis to identify "worst-case" scenarios and ensure the new components meet or exceed the performance of the predicate.
8. The Sample Size for the Training Set
Not applicable. There is no training set in the context of mechanical performance testing of a physical device.
9. How the Ground Truth for the Training Set Was Established
Not applicable. As there is no training set, this question is not relevant.
§ 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.