(58 days)
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, traumatoid arthritis, rheumatoid arthritis.
- Avascular necrosis of femoral condyle.
- · Post traumatic loss of joint configuration.
- · Primary implantation failure.
GMK Sphere can be implanted using a kinematic alignment approach. When a kinematic alignment approach is utilized, this knee replacement system is indicated in the following cases:
- · Severely painful and/or disabled joint as a result of arthritis, traumatoid arthritis or polyarthritis.
- · Collagen disorders, and/or avascular necrosis of the femoral condyle.
- · Moderate valgus, varus, or flexion deformities.
Tibial wedges cemented are to be attached to the tibial baseplate with both the fixing cylinders and bone cement. The screwed tibial augments are for screwed fixation to the tibial baseplate.
In case a semi-constrained liner is used, an extension stem must be implanted both on the femoral components. In case a GMK Revision tibial tray is used, an extension stem must be implanted.
The GMK Sphere Flex insert E-CROSS (Vitamin E Highly Crosslinked UHMWPE) , GMK Sphere CR E-CROSS (Vitamin E Highly Crosslinked UHMWPE) inserts and the Resurfacing Patella (Vitamin E Highly Crosslinked UHMWPE) are a line extension to the GMK Sphere Total Knee System and are:
- o Tibial insert Fixed Sphere FLEX: Left and Right, Sizes 1-6, Thicknesses 10-11-12-13-14-17-20 mm, E-cross-Vitamin-E Highly Crosslinked UHMWPE;
- Tibial Insert Fixed SPHERE CR: Left and Right, Sizes 1-6, Thicknesses 10-11-12-13-● 14mm, E-cross-Vitamin-E Highly Crosslinked UHMWPE;
- Patella resurfacing E-Cross: Sizes 1-4 E-Cross Vitamin-E Highly Crosslinked ● UHMWPE
GMK Sphere implants are sterile implantable devices designed for tricompartmental replacement of the natural knee joint.
They are a line extension to Medacta previously cleared implants: GMK Sphere (K121416), GMK Sphere Extension, (K140826), GMK Knee Prosthesis- GMK Sphere Tibial Insert Flex (K162035), GMK Sphere CR Tibial Inserts (K181635) and GMK Total Knee System (K0909889) and GMK Resurfacing Patella Size 4 (K113571).
Liners and Resurfacing patella subject of this submission are implants made of E-Cross (Vitamin-E Highly Crosslinked UHMWPE).
The introduction of the subject items do not require additional instrumentation needed during the surgical procedure and do not alter the indented use or outcomes.
The provided text describes a 510(k) premarket notification for a medical device, which focuses on demonstrating substantial equivalence to predicate devices rather than proving the device meets specific acceptance criteria through a standalone study with clinical outcomes. Therefore, much of the requested information (such as sample sizes for test sets, data provenance, number of experts for ground truth, adjudication methods, MRMC studies, and detailed ground truth establishment for training sets) is not applicable or not provided in this type of submission.
The "acceptance criteria" here primarily refer to the documented performance standards that the device must meet to demonstrate its safety and effectiveness, usually through non-clinical (mechanical) testing, in comparison to the predicate device.
Here's the information that can be extracted and inferred from the document:
1. Table of Acceptance Criteria and Reported Device Performance
The document lists several performance tests conducted. The acceptance criteria for these tests are generally that the new device performs equivalently to or better than the predicate devices, or within established limits for such devices, as per relevant standards. Specific numerical acceptance criteria or detailed reported performance values are not explicitly given in this summary document, but the conclusion states that the tests demonstrated safety and effectiveness.
| Test Performed | Acceptance Criteria (Inferred) | Reported Device Performance (Inferred) |
|---|---|---|
| GMK® SPHERE TIBIAL INSERTS MADE OF E-CROSS (VITAMIN E HIGHLY CROSSLINKED UHMWPE) | ||
| Constraint A/P Draw Test | Performance equivalent to predicate devices or within established limits for knee inserts. | Tests demonstrated that the new E-Cross inserts are as safe and effective as the predicate devices. (Per Report A.1) |
| M/L Shear Test | Performance equivalent to predicate devices or within established limits for knee inserts. | Tests demonstrated that the new E-Cross inserts are as safe and effective as the predicate devices. (Per Report A.1) |
| Rotary Laxity Test | Performance equivalent to predicate devices or within established limits for knee inserts. | Tests demonstrated that the new E-Cross inserts are as safe and effective as the predicate devices. (Per Report A.1) |
| Wear Test in Knee Simulator Machine with Load Control | Wear characteristics equivalent to or better than predicate devices, adhering to relevant standards (e.g., ISO 14243). | Tests demonstrated that the new E-Cross inserts are as safe and effective as the predicate devices. (Per Report A.2) |
| Maximum Postero-Anterior Load that can occur on the Tibial Insert During Activities of Daily Living | Ability to withstand typical physiological loads without failure, equivalent to predicate devices. | Tests demonstrated that the new E-Cross inserts are as safe and effective as the predicate devices. (Per Report A.3) |
| Dynamic Endurance Test Under PA Load | Endurance life equivalent to or exceeding predicate devices, meeting relevant fatigue standards. | Tests demonstrated that the new E-Cross inserts are as safe and effective as the predicate devices. (Per Report A.4) |
| GMK-SPHERE RESURFACING PATELLA MADE OF E-CROSS (VITAMIN E HIGHLY CROSSLINKED UHMWPE) | ||
| Contact Pressure and Areas | Contact mechanics (pressure and area) comparable to predicate patella components to ensure proper load distribution and minimize wear. | Tests demonstrated that the new E-Cross Resurfacing Patella is as safe and effective as the predicate devices. (Per Report A.5) |
| GMK®-SPHERE E-CROSS TIBIAL INSERTS | ||
| Contact Pressure and Areas: Comparative Analysis Between E-CROSS and UHMWPE Devices | Contact mechanics (pressure and area) comparable or improved compared to non-E-CROSS (traditional UHMWPE) versions to ensure proper load distribution and minimize wear. | Comparative analysis performed; results support the new E-Cross inserts are as safe and effective as the predicate devices. (Per Report A.6) |
| MATERIAL CHARACTERIZATION OF MEDACTA'S VITAMIN E HIGHLY CROSSLINKED UHMWPE (E-CROSS) | Material properties (e.g., mechanical strength, oxidation resistance, crosslinking density) meet established specifications for medical-grade UHMWPE and are suitable for the intended use, and are comparable to or improved over predicate materials. | Material characterization was performed; results support the new E-Cross inserts and Patella are as safe and effective as the predicate devices. |
| PYROGENICITY (Bacterial Endotoxin Test (LAL test) and Pyrogen test according to USP chapter ) | Absence of pyrogens as per European Pharmacopoeia §2.6.14 (equivalent to USP chapter ) and USP chapter . | Tests showed compliance with pyrogenicity standards (LAL test and USP ). The devices are not labeled as non-pyrogenic or pyrogen-free. (Reported as compliant with standards in section VII) |
2. Sample size used for the test set and the data provenance
- Sample Size for Test Set: Not specified in the summary document. These are typically mechanical, benchtop tests, not clinical trials with patient populations.
- Data Provenance: The tests are "Non-Clinical Studies" and "Performance Data" conducted by Medacta International SA. The exact location of the testing laboratories (country) is not specified, but the company is based in Switzerland. The studies are prospective in the sense that they were designed and executed to support this submission.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- Not Applicable. For non-clinical, mechanical testing of medical devices, "ground truth" as established by medical experts (e.g., radiologists) is not relevant. The "ground truth" is defined by established engineering and material science standards and physical measurements.
4. Adjudication method for the test set
- Not Applicable. Adjudication methods like 2+1 or 3+1 are used in clinical studies or image interpretation studies where expert consensus is needed to define a definitive diagnosis or outcome. For mechanical engineering tests, results are based on objective measurements and adherence to specified test protocols and standards.
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 submission is for a knee implant component (tibial inserts and patella), not an AI-powered diagnostic or interpretive device. Therefore, MRMC studies are not relevant.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Not Applicable. This is a physical medical implant, not a software algorithm.
7. The type of ground truth used
- Defined by Mechanical Engineering Standards and Specifications: The "ground truth" for these tests is based on objective physical properties, mechanical performance criteria, and material characterization standards (e.g., ISO, USP, European Pharmacopoeia). These standards specify the acceptable ranges or thresholds for device performance.
8. The sample size for the training set
- Not Applicable/Not Provided. The concept of a "training set" is relevant for AI/machine learning models. For mechanical device testing, there isn't a "training set" in the same sense. Design and material selection for the device would have involved extensive R&D and prior testing, but this isn't framed as a "training set" within this regulatory context.
9. How the ground truth for the training set was established
- Not Applicable/Not Provided. As there is no "training set" in the AI sense, this question is not applicable. The design and material choices are based on established engineering principles and prior research in UHMWPE and knee arthroplasty.
§ 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.