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The NextStep Arthropedix Total Knee System is indicated in knee arthroplasty for reduction or relief of pain and/or improved knee function in skeletally mature patients with severe knee pain and disability due to rheumatoid arthritis, osteoarthritis, primary and secondary traumatic arthritis, polyarthritis, collagen disorders, avascular necrosis of the femoral condyle or pseudogout, posttraumatic loss of joint configuration, particularly when there is patellofemoral erosion, dysfunction or prior patellectomy, moderate valgus, varus, or flexion deformities.

The NextStep Arthropedix Total Knee System may also be indicated in the salvage of previously failed surgical attempts if the knee can be satisfactorily balanced and stabilized at the time of surgery.

The NextStep Arthropedix Total Knee System is designed for cemented use only.

The subject device submission includes a combination of devices based on previously cleared devices (K142649 and K150783) and devices with new designs. This submission will include several identical devices reviewed in K142649 and K150783, new devices not yet reviewed by FDA, and new cleaning, packaging, and sterilization validations for all implants. The subject device submission includes 2 system options for total knee replacement:

• Option 1 – Posterior Stabilized (PS), Cruciate Retaining (CR), and Ultra Congruent Cruciate Retaining (UC-CR) patellofemorotibial total knee replacement system that is based on the Progressive Orthopedic Total Knee System cleared in K142694 and K150783

  • Includes additional femoral component sizes, additional vitamin E UHMWPE material option for the symmetrical tibial inserts, and manufacturing patellar components from vitamin E UHMWPE only.

• Option 2 – Medial Pivot Total Knee System, including cruciate retaining (MP-CR) and cruciate substituting (MP-CS) tibiofemoral articulation

The provided FDA 510(k) clearance letter describes a medical device, the NextStep Arthropedix Total Knee System, but it is not a software device or an AI/ML device.

The document primarily focuses on the mechanical and material properties of a knee implant system, comparing it to predicate devices. There is no mention of "acceptance criteria" related to an algorithm's performance, nor is there a "study" involving data sets, expert ground truth, or statistical measures like sensitivity, specificity, or AUC, which are typical for AI/ML device evaluations.

Therefore, I cannot provide the requested information regarding acceptance criteria and studies for an AI/ML device from this document. The concepts of "test set," "data provenance," "number of experts," "adjudication method," "MRMC study," "standalone performance," "ground truth type," and "training set" are not applicable to the information provided in this 510(k) summary for a physical knee implant.

The "Non-Clinical and/or Clinical Tests Summary" section lists mechanical tests performed for the physical device, such as fatigue performance, interlock mechanism strength, and wear testing. These are physical tests, not evaluations of an AI algorithm's computational performance.

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The ROSA® Knee System for use with the ROSA® RECON platform is indicated as a stereotaxic instrumentation system for total knee replacement (TKA) surgery. It is to assist the surgeon in providing software-defined spatial boundaries for orientation and reference information to identifiable anatomical structures for the accurate placement of knee implant components.

The robotic arm placement is performed relative to anatomical landmarks as recorded using the system intraoperatively, and based on a surgical plan optionally determined pre-operatively using compatible X-ray or MRI based surgical planning tools.

It includes a robotic arm, an optical tracking system and accessories, software system, surgical instruments and accessories.

The ROSA® Knee System is designed for use on skeletally mature patient population. The targeted population has the same characteristics as the population that is suitable for the implants compatible with the ROSA Knee System.

The ROSA® Knee System is to be used with the following fixed bearing knee replacement systems in accordance with their indications and contraindications: NexGen CR, NexGen CR-Flex Gender, NexGen CR-Flex Gender, NexGen LPS, NexGen LPS-Flex, NexGen LPS-Flex Gender, Persona® CR, Persona Ti-Nidium® CR, Persona Ti-Nidium PS, Persona IQ®, Vanguard® CR, and Vanguard PS.

The ROSA® Knee System for use with ROSA® RECON Platform is used to assist surgeons in performing Total Knee Arthroplasty (TKA) with features to assist with the bone resections as well as assessing the state of the soft tissues to facilitate implant positioning intra-operatively.

The ROSA® Knee System uses a Non-Device Medical Device Data System (Non-Device-MDDS) called the Zimmer Biomet Drive Portal which manages the creation and tracking of surgical cases. The cases reside on the portal until they are uploaded to the ROSA® Knee System before surgeries.

If the case is image-based, a 3D virtual bone model is generated pre-operatively by the PSI systems (X-PSI Knee System or CAS PSI Knee System) to create a model of the patient's femur/tibia and allows for the preparation of a pre-operative surgical plan. An imageless option is also available where landmarks taken intra-operatively on the patient's bony anatomy are used to create the surgical plan. Accuracy of resections, knee state evaluation, and soft tissue assessment are the same between image-based and imageless options as they are always based on intraoperative landmarks.

The intraoperative workflow and surgical concepts implemented in the system remain close to the conventional TKA workflow. As such, at the time of the surgery and based on the surgical plan, the system mainly assists the surgeon for in (1) determining reference alignment axes in relation to anatomical landmarks, (2) planning the orthopedic implants location based on these reference alignment axes and orthopedic implant geometry (planning optionally based on a pre-operative plan using pre-operative imaging), and (3), and precisely positioning the cut guide relative to the planned orthopedic implant location by using a robotic arm.

This document is a 510(k) premarket notification from Orthosoft, Inc. (d/b/a Zimmer CAS) for their ROSA® Knee System. The purpose of this submission is to add an additional compatible FDA-cleared knee implant system (Persona Personalized Knee System) to the device's labeling.

Based on the provided text, the ROSA® Knee System is a stereotaxic instrumentation system used to assist surgeons in Total Knee Arthroplasty (TKA) surgery. It provides software-defined spatial boundaries for orientation and reference information for accurate knee implant component placement.

Here's an analysis of the acceptance criteria and study information, keeping in mind that this document describes an update (to include a new compatible implant) to an already cleared device, not an initial clearance. Therefore, the performance data presented is focused on demonstrating that this change does not negatively impact the existing safety and effectiveness.

1. A table of acceptance criteria and the reported device performance

The document does not provide a table of acceptance criteria with specific numerical performance metrics for the device itself (e.g., accuracy in mm or degrees). This is because the submission is for a modification to an already cleared device (K221928), and the performance testing is framed as demonstrating that the modification (adding a new compatible implant) does not negatively impact the performance previously established.

Instead, the "Summary of Performance Data (Nonclinical and/or Clinical)" section states:

2. Sample size used for the test set and the data provenance

The document does not specify the sample size for any test set in terms of patient data or clinical trials. The "performance testing" mentioned is "non-clinical," meaning it likely involved bench testing, simulations, or phantom studies rather than patient data.

• Sample Size: Not specified for non-clinical testing.
• Data Provenance: Not specified (e.g., country of origin). The testing is described as "non-clinical," implying laboratory or bench testing rather than patient data collection. The company is based in Canada.
• Retrospective/Prospective: Not applicable as it's non-clinical testing.

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

Not applicable. As the testing was "non-clinical," it would not involve expert human review of medical images or patient outcomes to establish ground truth in the traditional sense of an AI/human reader study. The ground truth would be based on engineering specifications and measurement tolerances.

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

Not applicable. There is no mention of human readers or an adjudication process for a test set, as the performance testing described is non-clinical.

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

No. An MRMC comparative effectiveness study was not done according to the provided text. The device is a stereotaxic instrumentation system, a robotic assistance system, not an AI imaging diagnostic aid designed to be interpreted by human readers. The purpose of this submission is to add a compatible implant, not to evaluate human reader performance with or without the system.

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

This is implicitly addressed by the "non-clinical performance testing." The device itself (the robotic system) has standalone performance metrics (e.g., accuracy of cuts, placement of guides). The document states that the analysis demonstrated that the subject device did not impact these existing performance characteristics. However, the specific metrics and results of such standalone performance are not detailed in this 510(k) summary, as it refers back to the original predicate device's clearance.

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

For a robotic surgical system, the ground truth for non-clinical testing would typically involve:

• Engineering Specifications: Pre-defined accuracy and precision targets (e.g., millimetric deviation for bone resections, rotational accuracy).
• Physical Measurements: Using metrology equipment to measure the actual cuts or placements on phantoms or cadaveric models against the planned surgical targets.
• Simulations: Computational models to predict performance based on design parameters.

The document does not explicitly state the specific type of ground truth but refers to "similar test methods and acceptance criteria to those used for the predicate device," which for this type of device would primarily be based on objective physical measurements against established engineering tolerances.

8. The sample size for the training set

Not applicable. The ROSA® Knee System is a robotic surgical assistance system, not an AI/Machine Learning diagnostic algorithm that requires a "training set" of data in the typical sense. Its functionality is based on established engineering principles, sensor data processing, and pre-programmed surgical workflows, not pattern recognition learned from a large dataset.

9. How the ground truth for the training set was established

Not applicable, as there is no "training set" in the context of an AI/ML algorithm. The "ground truth" for the device's development would be derived from anatomical studies, surgical principles, biomechanical modeling, and expert surgical input to define the desired outcomes and parameters for knee replacement.

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