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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.

NexGen TM Tibial Trays may be used with or without bone cement (biological fixation).

The NexGen Trabecular Metal (TM) Tibial Tray is part of the Zimmer NexGen family of semiconstrained, nonlinked condylar knee prostheses.

Here's a breakdown of the acceptance criteria and the study information for the NexGen ® Trabecular Metal™ Tibial Tray, based on the provided FDA 510(k) summary:

Acceptance Criteria and Device Performance

Study Details:

1. Sample size used for the test set and the data provenance:

   • No specific sample size for a test set is mentioned. The study primarily relies on mechanical testing for non-clinical performance and a comparison to a predicate device. The document does not describe a clinical study with human subjects for the purpose of primary device clearance, so there is no "test set" in the traditional sense of a clinical trial.
   • Data Provenance: The mechanical testing would have been conducted by Zimmer, Inc., likely in a laboratory setting, to compare the physical properties of the new device to the established properties of the predicate. This would be considered retrospective in the sense that the predicate device's performance data already existed.

2. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

   • This is not applicable as the study relies on mechanical testing against a predicate device, not on expert adjudication of clinical outcomes for a "test set." The "ground truth" for substantial equivalence rests on the established performance of the predicate device and the physical testing results.

3. Adjudication method (e.g. 2+1, 3+1, none) for the test set:

   • Not applicable, as there was no clinical test set requiring expert adjudication.

4. 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:

   • No. This device is a total knee prosthesis, and its clearance process did not involve MRMC studies, which are typically relevant for diagnostic imaging AI tools.

5. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:

   • Not applicable. This is a physical medical device (a knee implant), not an algorithm or AI system.

6. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):

   • The "ground truth" for the device's acceptable performance is primarily derived from the established performance and safety of the predicate device (NexGen Porous, Uncemented Tibial Baseplates), coupled with laboratory mechanical testing results proving equivalence. No clinical outcomes data for this specific device were needed for clearance.

7. The sample size for the training set:

   • Not applicable. This is a physical medical device, not a machine learning model, so there is no "training set."

8. How the ground truth for the training set was established:

   • Not applicable. As above, there is no training set for this type of device. The mechanical testing results serve as evidence to support the claim of substantial equivalence to the predicate device, whose "ground truth" efficacy and safety would have been established through its own clearance process (likely involving mechanical testing and potentially clinical data if it were a novel device at the time).

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