(74 days)
This device is indicated for patients with severe knee pain and disability due to: rheumatoid arthritis, osteoarthritis, traumatic arthritis, polyarthritis, collagen disorders, and/or avascular necrosis of the femoral condyle, post-traumatic loss of joint configuration, particularly when there is patellofemoral erosion, dysfunction or prior patellectomy, moderate valgus, varus, or flexion deformities, the salvage of previously failed surgical attempts or for a knee in which satisfactory stability in flexion cannot be obtained at the time of surgery.
This device is intended for cemented use only.
Specific uses with CR-Flex GSF or LPS-Flex GSF femorals: Provides increased flexion capability for patients who have both the flexibility and desire to increase their flexion range. The CR-Flex GSF femoral, when used with 90-prefix NexGen CR articular surfaces, 00-prefix 10, 12 or 14mm or 90prefix 17 or 20mm Prolong™ Highly Crosslinked Polyethylene CR articular surfaces, is designed for use with a functional posterior cruciate ligament and when load bearing range of motion (ROM) is expected to be less than or equal to 155 degrees. The LPS-Flex GSF femoral, when used with LPS-Flex articular surfaces, is designed for use with both cruciate ligaments excised and when load bearing ROM is expected to be less than or equal to 155 degrees.
The NexGen Knee GSF Femoral Components include both LPS-Flex GSF and CR-Flex GSF versions and are part of the Zimmer Flex-series of semiconstrained, nonlinked, condylar knee prostheses that are designed to have a maximum active flexion of 155 degrees. The GSF designation indicates that the design of the femoral component has been modified slightly to address specific anatomic features of the distal femur that can be seen in both male and female patients, but are more typical of a female patient.
Here's an analysis of the provided text regarding the acceptance criteria and supporting study for the NexGen® Knee Gender Solutions Female (GSF) Femoral Components:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria Category | Specific Criteria | Reported Device Performance |
|---|---|---|
| Substantial Equivalence | Demonstrates substantial equivalence to predicate devices (NexGen LPS-Flex knee, K991581; NexGen CR-Flex femoral component, K023211). | Mechanical testing and Finite Element Analysis of the NexGen Knee GSF Femoral Components indicate that they are substantially equivalent to the predicate devices. |
| Functional Equivalence | Except for modifications to address specific anatomic features typical of a female patient, these components are identical to their respective predicate device. | The GSF designation indicates that the design of the femoral component has been modified slightly to address specific anatomic features of the distal femur that can be seen in both male and female patients, but are more typical of a female patient. |
| Manufacturing/Sterilization | Packaged and sterilized using the same materials and processes as predicate devices. | The device is packaged and sterilized using the same materials and processes. |
| Clinical Performance | (No specific clinical acceptance criteria stated for this device, as clinical data was deemed not needed.) | Clinical data and conclusions were not needed for this device. |
2. Sample size used for the test set and the data provenance
- Sample Size for Test Set: Not applicable. The submission explicitly states "Clinical data and conclusions were not needed for this device." The primary evaluation relied on non-clinical testing (mechanical testing and Finite Element Analysis) and comparison to predicate devices, rather than a clinical test set with human subjects.
- Data Provenance: Not applicable for a human subject test set. The data provenance for the non-clinical mechanical testing and Finite Element Analysis would be internal laboratory data generated by Zimmer, Inc.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- Not applicable. No human subject test set was used, and therefore no ground truth established by experts in this context.
4. Adjudication method for the test set
- Not applicable. No human subject test set was used.
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 device is a total knee prosthesis, not an AI-assisted diagnostic tool or imaging device that would involve human readers.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Not applicable. This device is not an algorithm or software. The "standalone" performance here refers to the mechanical and analytical performance of the physical device components, which was assessed through non-clinical testing.
7. The type of ground truth used
- The implicit "ground truth" for the performance evaluation of this medical device is the established performance and safety characteristics of its predicate devices (NexGen LPS-Flex Knee and NexGen CR-Flex femoral component). The device is deemed safe and effective if it can demonstrate substantial equivalence to these legally marketed predicates through mechanical testing and component analysis.
8. The sample size for the training set
- Not applicable. This device is a physical implant, not an AI algorithm that requires a training set. The "training" in product development would refer to engineering design, CAD modeling, and material selection based on established bio-mechanical principles and previous device designs.
9. How the ground truth for the training set was established
- Not applicable. As noted above, this isn't an AI device with a training set. The design was informed by the established anatomical features and performance of prior generations of knee prostheses, particularly those with modifications for "female" anatomical characteristics. The "ground truth" for its design would be anatomical data, biomechanical principles, and the performance history of existing devices.
§ 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.