(28 days)
The Klassic™ Knee System is intended for prosthetic replacement with the use of bone cement in treatment of the following:
- · Patient conditions of non-inflammatory degenerative joint disease (NIDJD): avascular necrosis and osteoarthritis
- · Patient conditions of inflammatory joint disease (IJD): rheumatoid arthritis
- · Patients with failed previous surgery where pain, deformity, or dysfunction persists
- · Correctable varus-valgus deformity and moderate flexion contracture
- · Revision of a previously failed knee arthroplasty
- · Patients who require a total knee replacement
The Sombrero Patella component will be used in conjunction with the Klassic Knee System during total knee replacement. The component is manufactured from ultrahigh molecular weight polyethylene in four diameters and two thicknesses.
This is a 510(k) premarket notification for a medical device called the "Klassic Knee System," specifically discussing the Sombrero Patella component. 510(k) submissions don't typically include a study of device performance against acceptance criteria in the way a clinical trial or AI/software validation would. Instead, they focus on demonstrating substantial equivalence to a legally marketed predicate device.
Therefore, many of the requested categories (e.g., sample size for test set, number of experts, adjudication method, MRMC study, standalone performance, ground truth for test/training sets) are not applicable to the information provided in this 510(k) summary.
However, I can extract the information relevant to the preclinical testing and the determination of substantial equivalence.
Here's a breakdown of the available information in the requested format, with an emphasis on what is and isn't applicable for a 510(k) submission of this type:
1. Table of Acceptance Criteria and Reported Device Performance
| Criteria Category / Test | Specific Criteria Acknowledged (Implicit) | Reported Device Performance (Summary) |
|---|---|---|
| Premarket Acceptance | Substantial Equivalence to Predicate | Determined to be Substantially Equivalent to predicate devices. |
| Preclinical Testing | Comparable Contact Stress | Engineering analyses indicated comparable contact stress to predicate devices. |
| Comparable Mechanical Strength | Engineering analyses indicated comparable mechanical strength to predicate devices. | |
| Material | Ultrahigh Molecular Weight Polyethylene | Manufactured from ultrahigh molecular weight polyethylene, same material as predicate. |
| Geometry | Similar Dimensions & Design | Explicitly stated as substantially equivalent to predicate in geometry. |
| Method of Fixation | Similar Fixation Mechanism | Explicitly stated as substantially equivalent to predicate in method of fixation. |
2. Sample Size used for the test set and the data provenance
- Not Applicable in the traditional sense of a clinical or performance study. This is a 510(k) submission relying on preclinical engineering analyses and comparison to predicate devices, not a test set of patient data.
- The "test set" here would refer to the designs and materials of the Sombrero Patella and the predicate devices being physically and/or computationally analyzed. The document doesn't specify a numerical "sample size" for these analyses.
- Data Provenance: The analyses were performed internally by the manufacturer (TJO - Total Joint Orthopedics). This is preclinical, in-house engineering data.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- Not Applicable. The "ground truth" for a 510(k) of this nature is substantial equivalence to a predicate device based on material, design, and performance characteristics (evaluated through engineering analyses, not expert consensus on patient outcomes). The experts involved would be the engineers and regulatory professionals conducting the analyses and preparing the submission. No external panel of clinical experts is described for determining a "ground truth" for a test set.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
- Not Applicable. Adjudication methods are typically used in clinical trials or studies with human readers/raters where a consensus or tie-breaking mechanism is needed. This submission focuses on engineering analysis.
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 knee implant, not an AI/software device. MRMC studies are completely irrelevant in this context.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Not Applicable. This is a mechanical knee implant, not an algorithm or software. Standalone performance as described is irrelevant.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)
- The "ground truth" for this 510(k) is the established safety and effectiveness profile of the predicate devices (Klassic Knee Domed Patella (K112906) and Zimmer Natural Knee All Polyethylene Patella (K934695)). The new device is considered "substantially equivalent" if it meets similar performance characteristics as demonstrated by engineering analyses. There is no mention of pathology or clinical outcomes data for this specific submission for the Sombrero Patella.
8. The sample size for the training set
- Not Applicable. There is no "training set" in the context of a 510(k) mechanical device submission. This concept applies to machine learning algorithms.
9. How the ground truth for the training set was established
- Not Applicable. As there is no training set, this question is not relevant.
Summary of the Study that Proves the Device Meets Acceptance Criteria:
The "study" or justification for the Klassic Knee System's Sombrero Patella component meeting acceptance criteria is primarily a demonstration of substantial equivalence to two legally marketed predicate devices: the Klassic Knee Domed Patella (K112906) and the Zimmer Natural Knee All Polyethylene Patella (K934695).
This demonstration was achieved through preclinical engineering analyses. These analyses directly compared the Sombrero Patella to the previously cleared TJO Domed Patella in terms of:
- Contact stress
- Mechanical strength
The submission also asserts substantial equivalence based on similarities in:
- Intended use
- Material (ultrahigh molecular weight polyethylene)
- Geometry
- Method of fixation
The conclusion drawn from these analyses and comparisons (which are summarized in a "Design Control Activities Summary" not provided in full) was that "the Sombrero Patella met the pre-determined acceptance criteria for the verification activities" and is "substantially equivalent to the predicate devices." The FDA's review of this submission resulted in a determination of substantial equivalence, allowing the device to be marketed.
§ 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.