(26 days)
The OrthAlign Plus® System is a computer-controlled system intended to assist the surgeon in determining reference alignment axes in relation to anatomical and instructures during stereotactic orthopedic surgical procedures. The OrthAlign Plus® System facilitates the accurate positioning of implants, relative to these alignment axes. The system aids the surgeon in controlling leg length and offset discrepancies in Total Hip Arthroplasty.
Example orthopedic surgical procedures include but are not limited to:
- Total Knee Arthroplasty
- · Total Hip Arthroplasty: Anterior/Posterior
- · Unicompartmental Knee Arthroplasty: Tibial transverse resection
The OrthAlign Plus® System is a non-invasive computer assisted surgical navigation system for use in knee and hip arthroplasty procedures. The OrthAlign Plus® System is configured to detect, measure, and display angular and positional measurement changes in a triaxial format. The OrthAlign Plus® System 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.
The OrthAlign Plus® System comprises a single use computer module and reusable instrumentation.
Here's a breakdown of the acceptance criteria and study information for the OrthAlign Plus System, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state quantitative acceptance criteria (e.g., "accuracy must be within X degrees"). Instead, it describes performance testing that "confirms that the OrthAlign Plus® System can be used according to its intended use" and "meets design input requirements." The performance is reported in terms of general accuracy and reliability.
| Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|
| Integrity of software code and functionality | Software verification and validation ensured integrity, functionality, and reliability. |
| System meets design input requirements (clinical utility) | Customer requirements validated with an advising surgeon. |
| Accuracy of leg length and offset measurement | Bench testing with mechanical fixtures and foam models verified leg length and offset measurement accuracy. |
| Accuracy of scale reader measurement | Bench testing with mechanical fixtures and foam models verified updated scale reader measurement accuracy. |
2. Sample Size Used for the Test Set and Data Provenance
The document does not provide specific sample sizes for the test set used in the performance studies. It mentions "bench testing with mechanical fixtures and foam models," which implies in-vitro testing rather than human subject data.
- Sample Size (Test Set): Not specified (implied to be an unspecified number of mechanical fixtures and foam models).
- Data Provenance: In-vitro (bench testing). No country of origin is specified, but the applicant is US-based. The testing is retrospective in the sense that it's performed on existing models, not prospective patient studies.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document mentions "Customer requirements validation with an advising surgeon," implying at least one expert was involved in validating clinical utility. However, it does not specify the number of experts for establishing ground truth for the accuracy tests (leg length/offset, scale reader). For the bench tests, the "ground truth" would be the known, precisely measured values of the mechanical fixtures and foam models, rather than expert consensus on anatomical structures.
- Number of Experts: At least one "advising surgeon" for customer requirements validation.
- Qualifications of Experts: "Advising surgeon" (specific qualifications like years of experience or subspecialty are not provided).
4. Adjudication Method for the Test Set
The document does not describe an adjudication method for the performance testing. For bench testing with mechanical fixtures, adjudication in the sense of reconciling differing expert opinions on a common case would not be applicable, as the expected values are mechanically determined. For the customer requirements validation, it's likely a qualitative assessment of whether the system met the surgeon's expectations.
- Adjudication Method: Not applicable for accuracy testing; not specified for customer requirements validation.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was done
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not explicitly mentioned or described. The performance data focuses on system accuracy and validation against design requirements, not on the improvement of human readers (surgeons) with or without AI assistance.
- MRMC Study Done: No.
- Effect Size with AI vs. Without AI Assistance: Not applicable, as no MRMC study was performed.
6. If a Standalone (i.e. algorithm only without human-in-the loop performance) was done
The performance testing described, particularly the "System accuracy testing: bench testing with mechanical fixtures and foam models to verify leg length and offset and updated scale reader measurement accuracy," represents a form of standalone testing of the algorithm's output against a known physical ground truth. While the overall system is "computer-assisted surgical navigation" (implying human-in-the-loop during actual surgery), the accuracy verification of its measurements on models is essentially a standalone evaluation of its core calculation capabilities.
- Standalone Performance Done: Yes (accuracy testing on mechanical fixtures and foam models).
7. The Type of Ground Truth Used
- Ground Truth Type:
- Mechanically determined values: For the "system accuracy testing" of leg length, offset, and scale reader measurements, the ground truth was derived from the precisely known measurements of mechanical fixtures and foam models.
- Design input requirements/Clinical utility: For "customer requirements validation," the ground truth was the satisfaction of predefined design input requirements and the system's utility as assessed by an advising surgeon.
8. The Sample Size for the Training Set
The document primarily describes a device modification (Special 510(k)) and performance testing for that modification. It does not provide information about a "training set" for the algorithms. Given the nature of the device as a "computer-assisted surgical navigation system" that detects, measures, and displays angular and positional changes using inertial sensors, microcontrollers, and digital signal processors, it's less likely to involve a large-scale machine learning training dataset in the same way an image-based AI diagnostic device would. Its "algorithms" convert raw sensor outputs into spatial coordinates.
- Sample Size (Training Set): Not specified.
9. How the Ground Truth for the Training Set Was Established
As no training set is explicitly mentioned or described, the method for establishing its ground truth is also not provided. The system's operation appears to be based on physical principles and sensor data processing rather than learning from a large, annotated dataset.
§ 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).