(85 days)
The iTotal® CR Knee Replacement System is intended for use as a total knee replacement in patients with knee joint pain and disability whose conditions cannot be solely addressed by the use of a prosthetic device that treats only one or two of the three knee compartments, such as a unicondylar, patellofemoral or bicompartmental prosthesis. The Indications for Use include: Painful joint disease due to osteoarthritis, traumatic arthritis, rheumatoid arthritis or osteonecrosis of the knee. Post traumatic loss of joint function. Moderate varus, valgus or flexion deformity in which the ligamentous structures can be returned to adequate function and stability. Failed osteotomies, hemiarthroplasties, and unicondylar, patellofemoral or bicompartmental implants. The implant is intended for cemented use only.
The iTotal CR Knee Replacement System (hereafter referred to as the "iTotal CR KRS") is a patient-specific tricompartmental faceted posterior cruciate ligament (PCL) retaining knee replacement system. The iTotal CR KRS is a semi-constrained cemented knee implant which consists of a femoral, tibial, and patellar component. The product design 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 CT or MR scans) and a combination of proprietary and off the shelf software a patientspecific implant and related instrumentation are designed, that best meet the geometric and anatomic requirements of the specific patient. The femoral component is manufactured from cobalt chromium molybdenum ("CoCrMo") alloy. The tibial component includes a metal tray manufactured from CoCrMo alloy and either one or two polyethylene inserts manufactured from UHMWPE of identical configuration. The patellar component is manufactured from UHMWPE For user convenience, and similar to the predicate iTotal CR KRS, accessory orthopedic manual surgical instruments designed for use with the modified iTotal CR KRS are provided to assist with implantation. The ancillary instruments are provided sterile and for single-use only. These patient-specific instruments are provided to assist in the positioning of total knee replacement components intra-operatively and in guiding of the cutting of bone.
Here's an analysis of the provided text regarding the acceptance criteria and supporting study for the ConforMIS iTotal CR Knee Replacement System:
1. Table of Acceptance Criteria and Reported Device Performance:
The provided document does not explicitly state numerical acceptance criteria for the device's performance in a clinical or analytical study. Instead, the submission focuses on demonstrating substantial equivalence to existing predicate devices.
The "acceptance criteria" here are implicitly that the modified device performs similarly to or no worse than the predicate devices across various characteristics. The "reported device performance" is a confirmation that these characteristics are maintained or improved.
| Characteristic / Acceptance Criteria | Reported Device Performance (Modified Device vs. Predicate) |
|---|---|
| Indications for Use: Identical to predicate. | Identical to predicate. |
| Intended for Cement Use Only: Yes | Yes |
| Product Classification: Identical to predicate (21 CFR 888.3560 (JWH)). | Identical to predicate. |
| Components: Identical (Femoral, Metal Backed Tibial, Patellar). | Identical. |
| Materials: Identical (Femoral: CoCrMo; Tibial Tray: CoCrMo; Tibial Inserts: UHMWPE; Patellar: UHMWPE). | Identical. |
| Design: Identical (Knee joint patellofemorotibial semi-constrained cemented prosthesis). | Identical. |
| Principle of Operation: Identical (Cemented Use fixed Bearing Design). | Identical. |
| Patient Matched: Yes | Yes |
| Posterior Cruciate Ligament (PCL) Sparing: Yes | Yes |
| Instrumentation: Identical (Patient-specific Nylon jigs). | Identical. |
| Proprietary Software for Femoral Components: Upgrade from v3.0 to v4.0. | iTotalWorks version 4.0 |
| Proprietary Software for Tibial Components: Introduction of iTotalTib v1.0 (previously manual). | iTotalTib version 1.0 or manual process |
| Software Functionality: Software verification and validation testing for iTotalWorks v4.0 and iTotalTib v1.0. | Testing performed, demonstrating safety and substantial equivalence. |
| Non-clinical Laboratory Testing: Demonstrates safety and substantial equivalence. | Testing performed, demonstrating safety and substantial equivalence. |
2. Sample Size Used for the Test Set and Data Provenance:
- The submission does not mention a traditional "test set" in the context of clinical or analytical performance data from patient samples. The substantial equivalence is primarily based on device description, materials, design, and software verification/validation.
- Data Provenance: Not applicable in the sense of clinical patient data, as the study relies on software testing and device characteristic comparison.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications:
- Not applicable. This submission focuses on validating software and demonstrating equivalent physical/design characteristics to a predicate device, rather than assessing a device's diagnostic or clinical performance against expert-established ground truth from patient data.
4. Adjudication Method for the Test Set:
- Not applicable. No clinical test set requiring expert adjudication is described in the provided text.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done:
- No, an MRMC comparative effectiveness study was not done. The document explicitly states: "Clinical data is not necessary to demonstrate substantial equivalence."
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- While not a standalone clinical performance study, the submission does refer to "Software verification and validation testing of proprietary software iTotalWorks" and "Software verification and validation testing of proprietary software iTotalTib." This testing confirms the functionality and accuracy of the algorithms as they relate to the design and manufacturing of the patient-specific implants and instruments. This can be considered a form of standalone software validation, demonstrating the algorithm's performance in its specific intended function (designing the implant and instrumentation based on patient imaging).
7. The Type of Ground Truth Used:
- For the software verification and validation, the ground truth would have been established through design specifications, requirements documents, and potentially comparison to known good outputs or established engineering principles and measurements. For example, the software would be validated to ensure it accurately translates imaging data into the geometric specifications for the patient-specific implants and instruments within specified tolerances.
8. The Sample Size for the Training Set:
- Not applicable. The document does not describe a machine learning model that would require a "training set" in the typical sense of AI/ML-based diagnostic devices. The proprietary software mentioned (iTotalWorks and iTotalTib) likely refers to CAD/CAM software used for design and manufacturing, which does not typically undergo "training" with patient data in the same way an AI diagnostic algorithm would.
9. How the Ground Truth for the Training Set was Established:
- Not applicable. (See point 8).
§ 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.