(100 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, 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.
- 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.
The iTotal PS 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 compartments, such as a unicondylar, patellofemoral or bicompartmental prosthesis.
The Indications for Use include:
- Painful joint disease due to osteoarthritis, traumatic arthritis, rheumatoid arthritis, polyarthritis or osteonecrosis of the knee.
- Post traumatic loss of joint function.
- Moderate varus, valgus or flexion deformity.
- Failed osteotomies, hemiarthroplasties, and unicondylar, patellofemoral or bicompartmental implants.
- 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.
The iTotal® Knee Replacement Systems (hereafter referred to as the "iTotal® KRS") are patient specific tricompartmental faceted knee replacement systems. The iTotal® KRS are semi-constrained, cemented knee implants which consist of femoral, tibial, and patellar components.
Using patient imaging 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 (CR only) polyethylene inserts. The polyethylene inserts may be manufactured from either UHMWPE, or for iTotal CR KRS, a highly cross-linked Vitamin E infused polyethylene (iPoly XETM) The patellar component is also manufactured from either UHMWPE or from a highly cross-linked Vitamin E infused polyethylene (iPoly XETM).
For user convenience, and similar to the predicate iTotal KRS, accessory orthopedic manual surgical instruments designed for use with the modified iTotal® 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 the cutting of bone.
The function and general design features of the patient specific implants and ancillary instruments remain similar to those described in the predicate 510(k)'s K140423 and K140833.
The provided text describes a 510(k) premarket notification for the ConforMIS iTotal Cruciate Retaining Knee Replacement System (iTotal CR KRS) and ConforMIS iTotal Posterior Stabilized Knee Replacement System (iTotal PS KRS). It is a submission to establish "substantial equivalence" to legally marketed predicate devices, rather than a study demonstrating a novel device's performance against specific acceptance criteria.
Therefore, many of the requested elements about acceptance criteria, device performance metrics, sample sizes for test and training sets, expert qualifications, and adjudication methods are not applicable or explicitly stated in this type of regulatory document. The focus here is on demonstrating that the modified device is as safe and effective as a previously cleared device, rather than proving performance against new, quantitative acceptance criteria.
However, I can extract information related to the changes made and the testing performed to demonstrate substantial equivalence.
Here's a breakdown of the information available in the document, framed to address your questions where possible:
1. Table of Acceptance Criteria and Reported Device Performance
This document does not specify "acceptance criteria" in the sense of quantitative performance metrics for the device itself (e.g., accuracy, sensitivity, specificity). Instead, it aims to demonstrate "substantial equivalence" to a predicate device. The "performance" being evaluated is that the modified device, particularly its manufacturing software, retains the same functionality and characteristics as the predicate.
| Criterion Type (Implicit) | Acceptance Standard (Implicit, for Substantial Equivalence) | Reported Device "Performance" (Comparison to Predicate) |
|---|---|---|
| Design Changes | No changes that alter fundamental design. | Designs remain similar to K140423 and K140833. |
| Material Changes | No changes to materials. | No changes to materials. |
| Manufacturing Methods | No changes to manufacturing methods (beyond efficiency). | No changes to manufacturing methods (beyond efficiency). |
| Packaging | No changes to packaging. | No changes to packaging. |
| Sterilization | No changes to sterilization. | No changes to sterilization. |
| Software Functionality | Proprietary software modules (SegSurf, iTotal FemJigs, iTotalTib, iTotal TibJigs, iTotal iView) continue to perform as intended and support a device substantially equivalent to the predicate. | Software verification and validation testing performed for SegSurf (v3.0), iTotal FemJigs (v3.0), iTotalTib (v3.0), iTotal TibJigs (v2.0), and iTotal iView (v3.0). These are updated versions from the predicate. The document states these modifications primarily focus on increasing automation of the CAD manufacturing process via the proprietary software modules, implying functional equivalence. |
2. Sample Size for the Test Set and Data Provenance
- Test Set Sample Size: Not applicable. This submission focuses on demonstrating substantial equivalence through non-clinical testing, particularly software verification and validation, rather than a clinical test set of patients or anatomical data. The "test set" here refers to the software's internal testing of its CAD manufacturing process. No specific numbers of "cases" or "patients" are mentioned for this software testing.
- Data Provenance: Not applicable in the context of patient data. The "data" being evaluated is the software's output and internal workings.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications of those Experts
- Number of Experts: Not applicable. This document is about software updates for a medical device's manufacturing process, not expert review of medical images or patient outcomes.
- Qualifications of Experts: Not applicable.
4. Adjudication Method for the Test Set
- Adjudication Method: Not applicable. As there are no human readers or diagnostic interpretations being evaluated, there is no need for an adjudication method.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- MRMC Study Done: No. This is a 510(k) submission for a knee replacement system, specifically focusing on updates to its proprietary software for manufacturing. MRMC studies are typically used for evaluating diagnostic imaging systems or AI-assisted diagnostic tools by comparing human reader performance.
6. Standalone (i.e., algorithm only without human-in-the-loop performance) Study
- Standalone Study Done: Yes, in a sense, as the software's performance is evaluated independently of a human operator during the manufacturing process. The "non-clinical testing" involves "Software verification and validation testing of proprietary software" (SegSurf, iTotal FemJigs, iTotalTib, iTotal TibJigs, iTotal iView). This evaluates the algorithm's functional output (e.g., consistency of design generation) for its intended purpose in manufacturing. However, this is not a "standalone performance" in the context of, for example, an AI algorithm diagnosing disease from images.
7. Type of Ground Truth Used
- Type of Ground Truth: For the software verification and validation, the "ground truth" would be the expected and validated outputs of the software based on engineering specifications and existing design principles for knee replacement systems. This is an internal engineering "ground truth" rather than a clinical ground truth like pathology or patient outcomes. The software is expected to accurately translate patient imaging data into a patient-specific implant design that meets established anatomical and design requirements.
8. Sample Size for the Training Set
- Training Set Sample Size: Not explicitly stated, nor is the concept of a "training set" directly applicable in the same way it would be for an AI algorithm that learns from data. The software mentioned (SegSurf, iTotal FemJigs, etc.) appears to be rule-based or algorithmic software for CAD manufacturing, rather than a machine learning model that undergoes "training" on a dataset.
9. How the Ground Truth for the Training Set Was Established
- Ground Truth for Training Set: Not applicable in the context of an AI training set. If the software involves any machine learning components (which is not explicitly stated but implied by "proprietary software modules" being updated for "increasing automation"), the "ground truth" for its development would be based on expertly defined anatomical landmarks, surgical principles, and biomechanical requirements of knee replacement design. This would be established by engineers, orthopedic surgeons, and domain experts during the software's initial development and refinement.
§ 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.