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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), and moderate valgus, varus, or flexion deformities. The salvage of previously failed surgical attempts if the knee can be satisfactorily balanced and stabilized at the time of surgery. This device is intended for cemented use only Specific uses with CR-Flex femorals: Provides increased flexion capability for patients who have both the flexibility and desire to increase their flexion range. The CR-Flex femoral 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 NexGen CR-Flex femoral components 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. Except for modifications to allow flexion to 155 degrees, CR-Flex femoral components are identical to the predicate device. The modifications do not change the intended use or the fundamental scientific technology. The device is packaged and sterilized using the same materials and processes

Here's an analysis of the provided text, focusing on the acceptance criteria and study information:

Acceptance Criteria and Device Performance

The provided document describes a device modification for the NexGen® Complete Knee Solution Cruciate Retaining (CR)-Flex Femoral Components. As such, the acceptance criteria are primarily focused on demonstrating substantial equivalence to existing predicate devices rather than establishing new independent performance benchmarks.

Study Details

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

   • Test Set Sample Size: Not explicitly stated for a clinical test set. The document indicates "Performance testing completed as part of the design assurance procedure," which implies an engineering/bench test. There is no mention of a patient-based test set or its size.
   • Data Provenance: The document does not specify a country of origin for any data. The study is non-clinical (bench testing), so the concept of retrospective or prospective data from patients does not apply.

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

   • Not applicable. This was a non-clinical performance study.

3. Adjudication method for the test set:

   • Not applicable. This was a non-clinical performance study.

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 is a medical device (knee implant), not an AI diagnostic tool.

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

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

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

   • The "ground truth" for this device modification was based on engineering performance specifications and design principles to ensure "safe and effective and substantially equivalent" performance to the predicate devices. This would involve mechanical testing for attributes like wear, strength, and range of motion, rather than clinical ground truth from patients.

7. The sample size for the training set:

   • Not applicable. This is a medical device for which the submission relies on non-clinical performance testing and substantial equivalence to predicate devices, not machine learning model training.

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

   • Not applicable. See point 7.

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