(91 days)
The iTotal® CR Knee Replacement System (KRS) 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, patello-femoral or bi-compartmental 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, hemiarthoplasties, and unicondylar, patello-femoral or bi-compartmental implants.
The iTotal CR KRS 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 patient-specific implant is designed, that best meets 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.
Here's a summary of the acceptance criteria and study information for the ConforMIS iTotal® CR Knee Replacement System, based on the provided text:
Acceptance Criteria and Device Performance
| Acceptance Criterion | Reported Device Performance |
|---|---|
| Software Verification and Validation | Software verification and validation testing of proprietary software (SegSurf(T) version 2.0) was performed. |
| Substantial Equivalence to Predicate Device | The device was found to be substantially equivalent to the iTotal Cruciate Retaining Knee Replacement System (K094050 and K103117) based on non-clinical laboratory testing and a detailed device description. |
Study Details
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Sample sizes used for the test set and data provenance:
- Test Set Sample Size: Not specified. The document states "Nonclinical Testing: The determination of substantial equivalence for this device was based on a detailed device description. The following 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: Detailed software description and software verification and validation testing of proprietary software". This implies the "test set" primarily refers to the software itself rather than a patient cohort.
- Data Provenance: Not specified. The tests were "non-clinical laboratory testing" and focused on software and device characteristics.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts: Not applicable. The determination of substantial equivalence was based on software verification and validation and a detailed device description, not on expert-adjudicated patient data.
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Adjudication method (e.g., 2+1, 3+1, none) for the test set: Not applicable, as there was no expert adjudication of patient data for this submission.
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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: Not applicable. This submission concerns a physical knee replacement system and its associated software for patient-specific design, not an AI-assisted diagnostic or interpretative tool for human readers.
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If a standalone (i.e., algorithm only without human-in-the-loop performance) was done: Yes, in essence, a standalone evaluation of the algorithm (software) was performed through "Software verification and validation testing of proprietary software." The software (SegSurf(T) version 2.0) is described as using "patient imaging (either CT or MR scans) and a combination of proprietary and off the shelf software a patient-specific implant is designed, that best meets the geometric and anatomic requirements of the specific patient." This indicates the software operates independently to design the implant.
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The type of ground truth used (expert consensus, pathology, outcomes data, etc.): The "ground truth" for the software's performance would internally be defined by the accuracy and precision of its design functions against predetermined anatomical and mechanical specifications, likely derived from engineering principles and clinical requirements for knee implants. No external ground truth from patient pathology or outcomes data is mentioned for this specific submission's verification and validation process.
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The sample size for the training set: Not specified. The document refers to "proprietary and off the shelf software" for designing patient-specific implants using imaging data, but does not detail the training set used for any machine learning components within this software.
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How the ground truth for the training set was established: Not specified.
§ 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.