(337 days)
The ConforMIS Tri-compartmental Resurfacing Device (tCR)is a minimally invasive, bone preserving primary total knee system intended for use in patients with severe knee joint pain and disability. The indications for use include restoring joint function and relief of pain due to:
- Painful joint disease due to osteoarthritis, traumatic arthritis, rheumatoid . arthritis of the knee
- Post traumatic loss of joint function .
- Mild to moderate valgus or varus deformity of the knee .
The ConforMIS Tri-compartmental Resurfacing (tCR) Device is intended only for use with bone cement.
The ConforMIS, Inc., Tri-Compartmental Resurfacing (tCR) Device is a tricompartmental semi-constrained total knee implant. The design of the product incorporates a bone preserving approach, with minimal bone resection of the tibia and femur, for the treatment of severe pain and/or disability of a knee damaged by osteoarthritis or trauma. Using patient imaging (either MRI or CT scans) a patient specific implant is designed that best meets the geometric and anatomic requirements of the specific patient. The treatment allows for the placement of a cemented metallic device designed from the patient's natural bone geometry. The femoral component is manufactured from cobalt chromium molybdenum alloy (ASTM-F-1537) from specific design drawings created from data obtained from images of the patient's individual geometry obtained using either MRI or CT scans. ConforMIS, Inc., implant Software is used to remove surface defects to produce a working design image of a smooth surface. Off the Shelf (OTS) software is utilized to produce the surface design. Subsequently, Solid Works OTS software is used to create the ConforMIS, Inc. Implant Engineering Drawing. The implant is manufactured using multiple SLA and standard casting techniques. The tibial component is manufactured from UHMWPE (ASTM-F-648) from a drawing produced in a similar manner to the femoral component. It is individualized on its footprint to match the patient's tibial anatomy. The articular surface is designed to be flat in the periphery and slightly concave in the femoral contact area. The all polyethelene (UHMWPE) component is designed for use with bone cement and central cement retention features will be incorporated on the undersurface of the implant. The circumferential size and shape of the tibial component are designed to be 1-3mm within the articulating surface borders of the tibia at the cut bone depth. The minimal polv thickness is 7mm and the component is designed to replace a bone cut of 2-6mm (measured distally from the lowest point of the bony surface of the affected condyle). The patellar component is also manufactured from UHMWPE.
The provided 510(k) summary for the ConforMIS Tri-Compartmental Resurfacing (tCR) Device does not contain information about acceptance criteria or a specific study proving the device meets said criteria in the format typically used for AI/ML device evaluations (e.g., sensitivity, specificity, accuracy against a defined ground truth).
The document focuses on demonstrating substantial equivalence to existing predicate devices based on design, materials, manufacturing process, equipment, and indications for use. The evaluation methodology described is primarily biomechanical testing rather than performance against a clinical ground truth.
Here's an analysis of the available information:
1. Table of Acceptance Criteria and Reported Device Performance:
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Substantial Equivalence to Predicate Devices | - Technological Characteristics: The ConforMIS tCR Device is stated to be "substantially equivalent to those of the cited predicate orthopedic devices" (ConforMIS Knee Interpositional Device K033242, ConforMIS Unicompartmental K043570) in terms of design process, materials, production process, and equipment. The image analysis for patient-specific implant design is identical to that used for the predicate ConforMIS devices. |
| - Indications for Use: Substantial equivalence is supported by the predicate devices (Biomet Anatomic Total Knee Prosthesis K000978, Advance® Total Knee system K974328, Alaron Surgical Active Knee® System K021740) for treating osteoarthritic knees where total knee replacement is warranted. | |
| Device Design Evaluation | - Standardized Biomechanical Testing: "The device design was evaluated using standardized fatigue, constraint and contact area biomechanical testing." |
| Safety and Effectiveness | - "The ConforMIS, Inc. Tri-Compartmental Resurfacing (tCR) Device raises no new safety or effectiveness issues." (This is a conclusion based on the substantial equivalence argument and testing). |
2. Sample Size Used for the Test Set and Data Provenance:
- Not Applicable in the traditional sense for AI/ML. The document describes biomechanical testing and comparison to predicate devices, not an evaluation against a clinical test set of patient data with a defined ground truth for performance metrics.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:
- Not Applicable. Ground truth, in the context of clinical expert consensus for AI/ML device evaluation, is not mentioned as the evaluation method. The primary "ground truth" for the biomechanical testing would be established engineering standards and physical measurements.
4. Adjudication Method for the Test Set:
- Not Applicable. No expert adjudication method is described, as the evaluation is based on biomechanical tests and comparison to predicate devices.
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 study was not done. This type of study focuses on improving human reader performance with AI assistance, which is not the evaluation method described for this knee implant device.
6. If a Standalone (i.e., algorithm-only without human-in-the-loop performance) was done:
- Not Applicable in the context of clinical performance evaluation. The device itself is a physical implant. While there is "ConforMIS, Inc., implant Software" used to process imaging data for custom implant design, the document states "The image analysis is identical with that used for the ConforMIS interpositional device (iPD) and the ConforMIS unicondylar implant." This implies the software component was previously evaluated or deemed substantially equivalent based on its use in prior cleared devices, rather than a standalone clinical performance study specifically for this tCR device's software. The document focuses on the end-device's substantial equivalence.
7. The Type of Ground Truth Used:
- For the biomechanical testing: Engineering standards and physical measurements (e.g., fatigue limits, constraint forces, contact area measurements).
- For the overall substantial equivalence claim: Performance and safety of legally marketed predicate devices.
8. The Sample Size for the Training Set:
- Not Applicable in the context of AI/ML model training on clinical data. The "design" or "training" data refers to patient imaging (MRI or CT scans) used for individual patient-specific implant design. It's not a "training set" for a generalizable AI model in the typical sense. Each implant design uses data from a single patient.
9. How the Ground Truth for the Training Set was Established:
- Not Applicable. For the patient-specific implant design, the "ground truth" is the patient's own anatomy as captured by MRI or CT scans. The "ConforMIS, Inc., implant Software" processes this anatomical data, and "Off the Shelf (OTS) software is utilized to produce the surface design." The "ground truth" for the software's accuracy in capturing anatomy would likely have been established during the development and clearance of the earlier ConforMIS interpositional and unicondylar devices, but specific details are not provided in this document.
In summary: This 510(k) summary is for a physical medical device (knee implant) and demonstrates substantial equivalence through comparison to predicate devices and biomechanical testing, rather than through clinical performance studies against defined ground truth as would be typical for an AI/ML diagnostic or prognostic device. The software mentioned is for patient-specific design, and its performance is referenced by its prior use in predicate devices.
§ 888.3560 Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis.
(a)
Identification. A knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace a knee joint. The device limits translation and rotation in one or more planes via the geometry of its articulating surfaces. It has no linkage across-the-joint. This generic type of device includes prostheses that have a femoral component made of alloys, such as cobalt-chromium-molybdenum, and a tibial component or components and a retropatellar resurfacing component made of ultra-high molecular weight polyethylene. This generic type of device is limited to those prostheses intended for use with bone cement (§ 888.3027).(b)
Classification. Class II.