(74 days)
Trabecular Metal Tibial Cone Augments are intended for use where severe degeneration, trauma, or other pathology of the knee joint indicates total knee arthroplasty. When used with the NexGen Complete Knee Solution - Rotating Hinge Knee (RHK) System, the Trabecular Metal Tibial Cone Augments are for cemented use only. When used with the NexGen Complete Knee Solution - Legacy Constrained Condylar Knee System, the Trabecular Metal Tibial Cone Augments are for cementless or cemented use.
The existing, commercially available NexGen® Trabecular Metal™ Tibial Cone Augments are manufactured wholly of Trabecular Metal porous tantalum, the same material that comprises numerous medical devices intended for use in orthopedic applications. The devices which are the subject of this 510(k), the modified NexGen Trabecular Metal Tibial Cone Augments are also manufactured of the same Trabecular Metal material, using the same methods as the predicate device. The existing, commercially available NexGen Trabecular Metal Tibial Cone Augments have tapered posterior, medial and lateral walls. The periphery of the inferior surface is smaller than that of the superior surface. A similar taper pattern is also present in the modified tibial cones.
Both the modified tibial cones augments and the existing, commercially available tibial cone augments are to be used in conjunction with Zimmer's NexGen® Complete Knee Systems- both the Legacy® Constrained Condylar Knee (LCCK) Stemmed Tibial Bases and the tibial component of Zimmer's Rotating Hinge Knee (RHK) System. Fixation of all of the cone augments to the tibial implant is accomplished by cementing the superior portion of the augment to the underside of the tibial baseplate. Apposition of the cone to bone inside the medullary canal is with or without cement when used with the LCCK tibial implant and with cement for the RHK tibial implant. With all of these tibial cone augments the LCCK tibial baseplate inferior surface must be cemented to the bone and the required stem extensions can either be cemented or press-fit.
The existing, commercially available augments come in four medium & large sizes, two height options and stepped augments. They can be used in conjunction with Zimmer's LCCK or RHK Knee Systems.
Here's an analysis of the provided text regarding the acceptance criteria and study for the Zimmer Trabecular Metal™ Tibial Cone Augments:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Mechanical Performance: Predetermined requirements established for mechanical performance during normal gait activities (walking and deep flexion). | Met: The results of testing and analyses conducted demonstrate that the proposed implants adequately meet the predetermined requirements established for its mechanical performance. |
2. Sample Size Used for the Test Set and Data Provenance
The study described is a Finite Element Analysis (FEA), which is a computer simulation, not a study involving physical samples or human patients as a "test set" in the traditional sense. Therefore, concepts like "sample size" for a test set and "country of origin of the data" are not directly applicable. The data provenance would be the computational models and parameters used in the FEA.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Their Qualifications
Since this was an FEA study, the concept of "ground truth" derived from expert review of patient data is not applicable. The "ground truth" for an FEA study would be the underlying physics and engineering principles validated through previous research and material properties. The document does not specify experts involved in establishing this, but it implies reliance on established engineering and biomechanical principles.
4. Adjudication Method for the Test Set
Not applicable for an FEA study, as there is no human interpretation of data for adjudication.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size of Human Improvement with AI vs. Without AI Assistance
No, an MRMC comparative effectiveness study was not done. This device is a physical implant, not an AI or imaging diagnostic tool, so "human readers" and "AI assistance" are not relevant to this submission.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
Again, this is not applicable as the device is a physical implant. The "standalone" performance here refers to the mechanical performance of the implant itself, which was assessed through the FEA.
7. The Type of Ground Truth Used
The ground truth used in this context is computational modeling and engineering principles, specifically validated through a Finite Element Analysis (FEA). The results of the FEA are compared against predetermined requirements for mechanical performance.
8. The Sample Size for the Training Set
Not applicable in the context of an FEA study. FEA models are built based on material properties, design specifications, and biomechanical loads. There isn't a "training set" of data in the sense of machine learning.
9. How the Ground Truth for the Training Set Was Established
As above, the concept of a "training set" doesn't directly apply. The "ground truth" for an FEA model would be based on well-established engineering principles, material science data for Trabecular Metal and bone, and biomechanical studies defining forces during gait. These parameters are inputs to the FEA, not derived from a "training set" in the typical sense.
Summary of the Study:
The study undertaken to demonstrate device performance was a comparative Finite Element Analysis (FEA). This computational modeling technique was used to simulate the mechanical behavior of the proposed modified tibial cone augments under "normal gait activities (walking and deep flexion)." The goal was to determine if the modified design met predefined mechanical performance requirements and to compare its performance to the predicate device, thereby supporting substantial equivalence. The document states that the FEA results demonstrated that the implants adequately meet the predetermined requirements established for its mechanical performance, thus supporting their substantial equivalence.
§ 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.
(a)
Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented 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 is designed to achieve biological fixation to bone without the use of bone cement. This identification includes fixed-bearing knee prostheses where the ultra high molecular weight polyethylene tibial bearing is rigidly secured to the metal tibial base plate.(b)
Classification. Class II (special controls). The special control is FDA's guidance: “Class II Special Controls Guidance Document: Knee Joint Patellofemorotibial and Femorotibial Metal/Polymer Porous-Coated Uncemented Prostheses; Guidance for Industry and FDA.” See § 888.1 for the availability of this guidance.