(42 days)
The iTotal® CR Knee Replacement System (iTotal CR 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 CR Knee Replacement System (hereafter referred to as the "iTotal CR KRS") is a patient specific tricompartmental faceted posterior cruciate liqament (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.
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. The polyethylene inserts may be manufactured from UHMWPE or from a highly cross-linked Vitamin E infused polyethylene (iPoly XE™). The patellar component is also manufactured from UHMWPE or from a highly cross-linked Vitamin E infused polyethylene (iPoly XE).
For user convenience, and similar to the predicate iTotal CR KRS, accessory orthopedic manual surqical 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 intraoperatively and quiding the cutting of bone.
The function and general design features of the patient specific ancillary instruments remain similar to those described in the predicate 510ks i.e. K120316 and K122870.
The provided document is a 510(k) summary for the ConforMIS iTotal® CR Knee Replacement System. It describes the device, its intended use, and the testing performed to demonstrate substantial equivalence to a predicate device. However, it does not contain the specific information requested about acceptance criteria for device performance, a study proving the device meets these criteria, or details regarding sample sizes, data provenance, expert ground truth, adjudication methods, MRMC studies, or training set information.
Instead, the document focuses on:
- Device Description: The iTotal CR Knee Replacement System is a patient-specific tricompartmental faceted PCL-retaining knee replacement system.
- Indications for Use: Detailed conditions for which the device is intended.
- Substantial Equivalence: The primary goal of the 510(k) submission, by comparing the modified device to previously cleared predicate devices (K120316 and K122870).
- Nonclinical Testing: A list of types of nonclinical laboratory testing performed (Tibial interlock assembly and disassembly testing, Contact area/contact stress testing, Constraint testing, Cadaveric testing) to demonstrate safety and substantial equivalence.
Therefore, many of your requested fields cannot be filled from the provided text. The document explicitly states: "Clinical data is not necessary to demonstrate substantial equivalence." This means a clinical study, as you might expect for many of the questions asked, was not performed and is not detailed here.
Here's a breakdown of what can be extracted and what cannot:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Not specified in the document. The document details types of nonclinical tests performed (e.g., "Tibial interlock assembly and disassembly testing," "Contact area/contact stress testing," "Constraint testing," "Cadaveric testing") but does not provide specific quantitative acceptance criteria or the numerical results of these tests. Instead, it concludes that based on these tests, the modified device is "substantially equivalent" to predicate devices. |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set: Not specified. The document mentions "Cadaveric testing" as one of the nonclinical tests, implying biological samples were used, but no numbers are provided.
- Data Provenance: Not specified for the nonclinical tests. As it's nonclinical (laboratory/cadaveric), geographical provenance is less relevant than for patient data. It is not retrospective or prospective in the sense of a clinical trial.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
- Not applicable/Not specified. The testing described is nonclinical (mechanical/cadaveric), and therefore, the concept of "experts establishing ground truth" in the diagnostic or clinical outcome sense does not apply. The tests likely followed established engineering or biomechanical testing standards.
4. Adjudication Method for the Test Set
- Not applicable/Not specified. Adjudication methods (like 2+1 or 3+1) are typically used for clinical interpretation tasks involving expert consensus, which is not described here.
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 MRMC study was done. This device is a knee implant system and associated surgical instrumentation, not an AI-assisted diagnostic tool. 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 the device uses "a combination of proprietary and off-the-shelf software" for patient-specific implant design based on patient imaging (CT or MR scans), the document does not describe standalone algorithm performance for diagnostic or analytical tasks. The software is part of the design process for the physical implant, not a standalone diagnostic or interpretative algorithm. Therefore, typical standalone performance metrics (e.g., sensitivity, specificity, AUC) are not relevant or provided.
7. The Type of Ground Truth Used
- Type of Ground Truth: For the nonclinical tests, the "ground truth" would be based on engineering specifications, biomechanical principles, and established test standards (e.g., for contact area/stress, constraint, interlock functionality). For "cadaveric testing," the ground truth would be the direct observation and measurement of the implant's behavior within the cadaveric model according to predefined experimental protocols. It is not expert consensus, pathology, or outcomes data in the clinical sense.
8. The Sample Size for the Training Set
- Not applicable/Not specified. The document does not describe an AI or machine learning model that would require a "training set" in the traditional sense for diagnostic or predictive tasks. The software develops patient-specific designs based on individual patient imaging, not by "training" on a large dataset to learn patterns for diagnosis.
9. How the Ground Truth for the Training Set Was Established
- Not applicable/Not specified, as no training set for a machine learning model is described. The "ground truth" for the design software would be derived from anatomical principles, biomechanical models, and engineering specifications used to program the design algorithms.
§ 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.