(104 days)
The ConforMIS Unicondylar Knee Replacement System (iUni) is intended for use in one compartment of the osteoarthritic knee to replace the damaged area of the articular surface in patients with evidence of adequate healthy bone sufficient for support of the implanted components.
Candidates for unicondylar knee replacement include those with:
- joint impairment due to osteoarthritis or traumatic arthritis of the knee .
- previous femoral condyle or tibial plateau fracture, creating loss of function .
- valgus or varus deformity of the knee .
- o revision procedures provided that anatomic landmarks necessary for alignment and positioning of the implant are identifiable on patient imaging scans
This implant is intended for cemented use only.
ConforMIS iUni Unicondylar Knee Replacement System ("iUni KRS") is a patient-specific unicompartmental knee replacement system. The iUni KRS is comprised of a set of implants designed from patient images. The implant system consists of: 1 Femoral Implant t . 1 Tibial Component (all-polyethylene or metal backed) The implants of the iUni KRS consists of individually packaged femoral and tibial components and are provided with ancillary instrumentation to assist in the implantation procedure. The patient-specific femoral implant is made of Cobalt Chrome Molybdenum alloy (CoCrMo) and is personalized to match a patient's anatomy. The all poly tibial component is made from UHMWPE. The metal backed tibial component consists of a CoCrMo tibial tray and with an Ultra High Molecular Weight Polyethylene (UHMWPE) tibial insert. Multiple inserts of varying thicknesses may be provided to accommodate surgeon preferences. The outline, the bone contacting surfaces, and the articular surfaces of the femoral component as well as the outline of both tibial components are personalized to match the patient's femoral and tibial anatomy. The design of the implant is derived from an analysis, using proprietary software, of images obtained by MRI or CT scan. Disposable, patient-specific instrumentation is provided to assist in the implantation of the iUni Unicondylar Knee Replacement System.
Here's an analysis of the provided text regarding the acceptance criteria and the study that proves the device meets them:
1. Table of Acceptance Criteria and Reported Device Performance
The provided text does not explicitly state specific acceptance criteria in terms of numerical performance metrics (e.g., accuracy, precision, sensitivity, specificity) for the software. Instead, it describes a process of "software verification and validation testing of proprietary software" to demonstrate substantial equivalence to a predicate device.
The "performance" reported is that the device, after software modifications, is substantially equivalent to the previous versions. This determination is based on the conducted non-clinical laboratory testing.
| Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|
| Software functions as intended and meets design specifications. | Detailed software description and software verification and validation testing of proprietary software SegSurf v3.0, iUniWorks v4.0, and iUni FemJigs v2.0 were performed. |
| Device maintains safety and effectiveness after software update. | Non-clinical laboratory testing was performed demonstrating that the device is safe and can be considered substantially equivalent to the predicate device for the intended use. Clinical data was not deemed necessary to demonstrate substantial equivalence. |
| Substantial Equivalence to Predicate Devices (K121974 & K111916). | "Based on the testing conducted it is concluded that the iUni Unicondylar Knee Replacement System with the use of SegSurf v3.0, iUniWorks v4.0, and iUni FemJigs v2.0 production software modules is substantially equivalent to the iUni Unicondylar Knee Replacement System" (predicate devices). |
2. Sample Size Used for the Test Set and Data Provenance
The document does not specify a sample size for a test set in the context of typical machine learning or algorithm validation. The testing described is "software verification and validation testing," which usually involves testing the software's functionality, compliance with requirements, and performance against defined specifications, rather than a clinical dataset.
The data provenance is not mentioned. Since this is a software update for a pre-existing medical device, the "data" being processed by the software would be patient imaging scans (MRI or CT) used to design the patient-specific implants. However, the origin and nature of any specific dataset used for the "verification and validation" of the software itself are not detailed.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Their Qualifications
Given that the study is a "software verification and validation testing" for substantial equivalence, and not a clinical efficacy or performance study involving human interpretation of imaging, there is no mention of experts being used to establish ground truth for a test set in the traditional sense of medical image analysis (e.g., radiologists marking lesions). The "ground truth" for software validation would typically relate to the accuracy of the software's output compared to its specified design or known correct outputs (e.g., if a measurement is supposed to be X, the software calculates X). The document does not detail this aspect.
4. Adjudication Method for the Test Set
As there is no mention of a test set requiring expert interpretation or labeling, there is no adjudication method described.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size
No MRMC comparative effectiveness study was done or reported. The submission focuses on demonstrating substantial equivalence of the modified software to a predicate device through non-clinical software testing, not on comparing human reader performance with or without AI assistance.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
The testing performed was standalone software verification and validation of SegSurf v3.0, iUniWorks v4.0, and iUni FemJigs v2.0. These software modules are proprietary and are used for "analysis... of images obtained by MRI or CT scan" to design patient-specific implants. This constitutes standalone algorithm testing, as it doesn't involve human interpretation of the algorithm's output in a diagnostic setting, but rather the internal validation of the software's calculations and functionalities.
7. The Type of Ground Truth Used
The ground truth for the "software verification and validation testing" would be the expected and correct outputs/behaviors of the software modules based on their design specifications and computational requirements. This is typically established through:
- Design specifications: What the software is designed to calculate or segment.
- Reference data/models: Using known inputs with manually calculated or established correct outputs to compare against the software's results.
- Mathematical correctness: Ensuring algorithms perform calculations accurately.
The document does not elaborate on the specific type of ground truth beyond stating "software verification and validation testing."
8. The Sample Size for the Training Set
The document does not provide information on the sample size for a training set. The described software (SegSurf, iUniWorks, iUni FemJigs) is for custom implant design based on individual patient imaging data. While these systems are likely built on underlying algorithms that may have been developed and trained using various datasets, the submission focuses on the validation of an updated version of these proprietary software modules. The training details of the original or updated algorithms are not part of this 510(k) summary.
9. How the Ground Truth for the Training Set Was Established
Since no information is provided about a training set, the method for establishing its ground truth is also not mentioned.
§ 888.3520 Knee joint femorotibial metal/polymer non-constrained cemented prosthesis.
(a)
Identification. A knee joint femorotibial metal/polymer non-constrained cemented prosthesis is a device intended to be implanted to replace part of a knee joint. The device limits minimally (less than normal anatomic constraints) translation in one or more planes. It has no linkage across-the-joint. This generic type of device includes prostheses that have a femoral condylar resurfacing component or components made of alloys, such as cobalt-chromium-molybdenum, and a tibial component or components made of ultra-high molecular weight polyethylene and are intended for use with bone cement (§ 888.3027).(b)
Classification. Class II.