(30 days)
Knee+ is a stereotaxic system including an intraoperative software as a medical device and surgical instruments. Knee+ is intended for primary Total Knee Replacement, to assist the surgeon in determining reference alignment axes in relation to anatomical landmarks, in order to position the cutting computed mechanical axis. The Knee+ includes smart glasses as a Head Mounted Device (HMD) for displaying information to the user intraoperatively. The smart glasses should not be relied upon solely and should always be used in conjunction with traditional methods.
The main purpose of Knee+ is to assist the surgeon during the primary Total Knee Replacement (TKR) intervention. Knee+ includes software and surgical instruments.
Knee+ provides information to help locate and orientate the main femoral and tibial cutting planes as required in knee replacement surgery. Knee+ allows the surgeon to adjust the cutting plane orientation and the resection level. This includes means for the surgeon to collect anatomical references during the TKR intervention using the surgical instruments. The software locates in a 3D reference frame the instruments which include markers. All collected coordinates are treated by software algorithms to provide the surgeon with relevant orientation of the tracked cutting guide. Knee+ software is installed on a wearable Head Mounted Device (HMD) which includes a camera and displays intraoperative information to the user. A near-eye display allows the surgeon to look at the HMD screen or the field of view when needed.
The provided text is a 510(k) summary for the medical device Knee+, documenting its substantial equivalence to a previously cleared version (K220104). The primary change in the subject device is the addition of an external camera to the Head-Mounted Device (HMD) for use under surgical helmets.
The document does not contain the detailed acceptance criteria or a comprehensive study report outlining the acceptance criteria and the performance data that proves the device meets those criteria in the format requested. While it refers to "performance data" and "acceptance criteria" from previous submissions, and mentions specific tests like ASTM F2554, it does not provide the specific numerical acceptance thresholds or the measured device performance against those thresholds in tabular format.
Therefore, I cannot fully answer your request by extracting the information directly from the provided text. The document states that "The same methods, protocols and acceptance criteria used to support the previously cleared K220104 were applied to evaluate the change." This implies that the specific details you're looking for would be in the K220104 submission, not in this K230789 summary.
However, I can extract and present the available relevant information regarding the study and testing performed to demonstrate substantial equivalence for the modifications in K230789:
Acceptance Criteria and Device Performance (Based on available information for K230789 modifications):
The document states that the same performance is still achieved with the modifications, and that "All performance testing demonstrates that Knee+ performs according to its specifications and functions as intended." While specific numerical criteria and reported performance values are not provided in this summary, the general areas of assessment and the type of criteria implicitly met are:
| Acceptance Criterion (Implicit/General) | Reported Device Performance (as stated in summary) |
|---|---|
| Repeatability (per ASTM F2554) | "Demonstrate that Knee+ performs according to its requirements and specifications when installed on the Head Mounted Device under a surgical helmet... repeatability was tested according to ASTM F2554." (Results deemed satisfactory as per conclusion of substantial equivalence) |
| Accuracy (per ASTM F2554) | "Demonstrate that Knee+ performs according to its requirements and specifications when installed on the Head Mounted Device under a surgical helmet... accuracy were tested according to ASTM F2554." (Results deemed satisfactory as per conclusion of substantial equivalence) |
| User Needs Validation (per IEC 62366-1) | "The system was validated in accordance with IEC 62366-1 by the intended users to ensure that the installation of the modified Head-Mounted Device and the user underneath surgical helmets do not raise new issues of safety or effectiveness." |
| Software Verification and Validation (per IEC 62304 & FDA Guidance) | "Software verification and validation testing were conducted as required by IEC 62304 and documentation was provided as recommended by FDA Guidance 'Content of Premarket Submissions for Software Contained in Medical Devices'." (Results deemed satisfactory towards safety and effectiveness) |
| Overall Safety and Effectiveness | "Performance data demonstrated that Knee+ is as safe and effective as its previous version... Thus, the Knee+ is substantially equivalent to the legally marketed predicate device." |
Study Details for K230789 (Focused on the modifications):
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Sample size used for the test set and the data provenance:
- Sample Size: Not explicitly stated in terms of number of cases or subjects. For bench testing (ASTM F2554), it would typically involve multiple measurements or runs. For user needs validation, it would involve a group of "intended users." The exact number is not provided.
- Data Provenance: The studies were performance bench testing and user validation studies conducted by the manufacturer, Pixee Medical. The text doesn't specify the country of origin of the data beyond "Besançon, FRANCE" as the submitter's address. The studies were likely prospective for the purpose of validating the new modification.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Number of Experts: Not specified.
- Qualifications of Experts: For the "User needs validation," the validation was performed by "intended users." While their specific qualifications (e.g., orthopedic surgeons) are not explicitly stated, it can be inferred that they are medical professionals who would use the device (i.e., surgeons). For bench testing, the "ground truth" would be established by the highly accurate measurement tools and methods used within the testing lab.
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Adjudication method for the test set:
- Not specified. Given the nature of bench testing and user needs validation in 510(k) submissions for modifications, formal multi-reader adjudication methods (like 2+1 or 3+1 often seen in diagnostic AI studies) are not typically described in this context for performance of the device's measurement capabilities. User needs validation would involve assessing user feedback and observations.
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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 explicitly stated or implied for this 510(k) submission. This submission focuses on demonstrating that the modified device maintains its previous performance and does not introduce new safety or effectiveness concerns, specifically regarding the addition of an external camera and use under surgical helmets. The device's primary function is to assist in surgical navigation, providing information, and the study did not aim to measure human reader improvement with AI assistance.
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If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- The document implies that standalone performance was assessed for the tracking system technology and accuracy of cut orientation and resection level through "Bench testing." This type of testing evaluates the algorithm's performance and the system's accuracy independent of a complex human interaction scenario, although it's within a controlled test environment.
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The type of ground truth used:
- For accuracy and repeatability (bench testing): The ground truth would be established by highly precise measurement instruments and reference standards (e.g., calibrated optical tracking systems, mechanical fixtures) that are part of the ASTM F2554 testing methodology.
- For user needs validation: The ground truth is the qualitative assessment of safety, effectiveness, and usability by the intended users in simulated or actual usage scenarios.
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The sample size for the training set:
- Not applicable / Not provided. The document describes a 510(k) submission for a modification to an already cleared device. It does not contain information about the training set size for the underlying algorithms, as this would have been established during the development and clearance of the original (K220104) or even earlier versions. The current submission focuses on verifying that the modification does not negatively impact existing performance.
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How the ground truth for the training set was established:
- Not applicable / Not provided. As mentioned above, this information pertains to the original algorithm's development, not the current modification's validation.
§ 882.4560 Stereotaxic instrument.
(a)
Identification. A stereotaxic instrument is a device consisting of a rigid frame with a calibrated guide mechanism for precisely positioning probes or other devices within a patient's brain, spinal cord, or other part of the nervous system.(b)
Classification. Class II (performance standards).