(84 days)
The KneeAlign™ System with Reference Sensor is a computer controlled system intended to assist the surgeon in determining reference alignment axes in relation to anatomical structures during stereotactic orthopedic surgical procedures. The KneeAlign™ System with Reference Sensor facilitates the accurate positioning of implants and instrumentation, relative to these alignment axes. Example orthopedic surgical procedures include but are not limited to: Total Knee Arthroplasty.
The KneeAlign System with Reference Sensor is an innovative non-invasive computer assisted surgical navigation system for use in knee arthroplasty procedures. The KneeAlign System is configured to detect, measure, and display angular measurement changes in a triaxial format. The KneeAlign System with Reference Sensor utilizes a palm-sized computer module and reference sensor to generate positional information in orthopedic procedures providing a sequence of steps for registration of anatomical landmarks, calculation of mechanical axes, and positioning of instruments relative to the mechanical axes. In knee arthroplasty procedures, the device assists the surgeon in establishing the mechanical axis of the tibia, determining the varus/valgus angle and the posterior slope angle of the cutting block relative to tibia. The KneeAlign System with Reference Sensor comprises a single use computer module and reusable instrumentation. The KneeAlign™ System with Reference Sensor comprises a single use computer module, a reusable reference sensor, and reusable tibial jig. The device utilizes algorithms to convert sensor outputs into spatial coordinates, providing graphical representation of instruments and anatomy on the user display screen.
The provided 510(k) summary for the KneeAlign™ System indicates that its acceptance criteria and the study proving it meets these criteria are primarily based on demonstrating substantial equivalence to predicate devices through various performance tests. However, the document does not explicitly state specific numerical acceptance criteria for accuracy or performance metrics, nor does it provide a direct table of acceptance criteria versus reported device performance.
Instead, the submission focuses on a comparative approach, asserting that if the device performs comparably to the legally marketed predicate devices, it is considered safe and effective.
Here's a breakdown of the information available and what is not explicitly stated:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Implied) | Reported Device Performance (Implied) |
|---|---|
| Functional Equivalence: Device performs its intended function (measuring and displaying angular changes/positional information for total knee arthroplasty) | "Simulated use testing confirms that the KneeAlign System with Reference Sensor can be used according to its intended use." The system is "configured to detect, measure, and display angular measurement changes in a triaxial format." It assists in "establishing the mechanical axis of the tibia, determining the varus/valgus angle and the posterior slope angle of the cutting block relative to tibia." |
| Accuracy: Device provides accurate positional information and alignment axes. | "System accuracy testing" was performed. The device "facilitates the accurate positioning of implants and instrumentation." While specifics are not provided, the claim of substantial equivalence implies that its accuracy is comparable to predicate devices. |
| Safety: Device is safe for its intended use, without posing undue risks to patients or users. | "Safety and performance...validated to insure it meets its intended use." This included: Bench Testing (system accuracy, performance, laser), Software Validation, Cleaning and Sterilization Validation, Biocompatibility Assessment, Electrical Safety and Electromagnetic Compatibility Testing (IEC 60601-1, IEC 60601-1-2), and Simulated Use/Cadaver Testing. |
| Substantial Equivalence: Device is as safe and effective as predicate devices. | "This testing regime demonstrates that the subject device is substantially equivalent to the legally marketed predicate devices, for its intended use." "The information provided by OrthAlign in this 510(k) application was found to be substantially equivalent to predicate devices..." "A technological comparison and bench, and cadaver testing demonstrate the substantial equivalence of the KneeAlign System with Reference Sensor to the predicate devices." |
| Compliance with Standards: Device meets relevant medical device standards. | Electrical Safety and Electromagnetic Compatibility Testing against "Safety Requirements for Medical Electrical Equipment (IEC 60601-1)" and "Electromagnetic Compatibility (EMC) Requirements (IEC 60601-1-2)." |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: Not explicitly stated. The document mentions "Simulated Use/Cadaver Testing," implying a test set was used, but the number of cadavers or simulated scenarios is not provided.
- Data Provenance: Not explicitly stated. The document doesn't mention the country of origin or whether the data was retrospective or prospective. Given it involves cadaver testing, it would be prospective data collection for the study itself.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
- This information is not provided in the document. Ground truth for cadaver studies typically involves direct measurement by a clinician or engineer, potentially verified by multiple individuals, but no details are given here.
4. Adjudication Method for the Test Set
- This information is not provided in the document.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
- No, a MRMC comparative effectiveness study was not done as described (human readers improving with AI vs. without AI assistance). This device is a surgical navigation system, not an AI diagnostic tool primarily evaluated by human readers interpreting images. Its "assistance" is for the surgeon during the procedure, not a post-hoc diagnostic interpretation by multiple readers.
- The comparison focuses on the device's performance against predicate devices and the standard of care (visual observation and tactile feedback or existing computer-assisted surgery devices), rather than quantifying human reader improvement with or without the device in an MRMC study setup.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
- Yes, implicitly. The "System accuracy testing" and other bench tests would constitute standalone performance evaluations of the device's algorithms and hardware without a human actively operating it in a surgical scenario. The "Simulated Use/Cadaver Testing" would then involve a human-in-the-loop, but the initial accuracy tests would be standalone.
7. The Type of Ground Truth Used
- For "System accuracy testing" and "Simulated Use/Cadaver Testing," the ground truth would likely be established through direct, precise measurements using highly accurate instruments (e.g., optical trackers, mechanical goniometers, or other measurement tools) independent of the device being tested. In cadaver studies, this often involves disarticulation and direct measurement of bone axes or angles after the device's measurements are recorded.
- The document does not explicitly state the methodology for establishing this ground truth.
8. The Sample Size for the Training Set
- This device is a rule-based or sensor-based system that applies algorithms to convert sensor outputs into spatial coordinates. This is generally not a machine learning/AI system that requires a "training set" in the common sense of supervised learning. Therefore, a training set in the context of machine learning is not applicable or discussed. The algorithms are likely pre-programmed and validated, not trained on a large dataset.
9. How the Ground Truth for the Training Set Was Established
- As noted above, a training set (in the machine learning sense) is not applicable here as the device operates on established biomechanical principles and sensor data processing rather than learning from data. The accuracy of the underlying algorithms would be validated through engineering principles and possibly through bench testing with known inputs and expected outputs.
§ 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).