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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® 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.

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 polyethylene inserts. The polyethylene inserts may be manufactured from either UHMWPE or iPoly XE™ (a highly cross-linked vitamin E infused polyethylene) The patellar component is also manufactured from either UHMWPE or iPoly XE.

For user convenience, and similar to the predicate iTotal CR KRS, patient specific accessory orthopedic manual surgical instruments designed for use with the proposed iTotal CR KRS are provided to assist in the positioning of the total knee replacement components intraoperatively and in guiding the cutting of bone. In addition, reusable orthopedic manual surgical instruments are provided separately.

The function and general design features of the patient specific implants and ancillary instruments remain similar to those described in the predicate 510(k), K160025.

The provided document is a 510(k) summary for the ConforMIS iTotal® Cruciate Retaining (CR) Knee Replacement System (iTotal CR KRS). It focuses on establishing substantial equivalence to a predicate device, specifically for an additional sterilization method (Ethylene Oxide) for certain components.

The information requested, which typically relates to the acceptance criteria and study data for device performance in relation to its intended clinical use (e.g., accuracy, sensitivity, specificity, or effects on human readers for AI/diagnostic devices), is not present in this document. This submission primarily deals with changes in manufacturing (sterilization methods) and material properties, rather than clinical efficacy or diagnostic performance. Therefore, the requested information about device performance against acceptance criteria for a "study that proves the device meets the acceptance criteria" in a clinical/diagnostic sense cannot be extracted from this text.

However, I can provide information on the acceptance criteria and supporting "study" (validation testing) related to the sterilization process as outlined in the document:

Here's the information regarding the sterilization validation:

1. Table of Acceptance Criteria and Reported Device Performance (related to sterilization)

2. Sample size used for the test set and the data provenance

The document does not specify exact sample sizes for the sterilization validation tests (e.g., how many devices or components were tested for SAL, residuals, or material properties).
The data provenance is from ConforMIS, Incorporated, the manufacturer of the device, implying the testing was conducted internally or by a contracted lab as part of their regulatory submission for a premarket notification (510(k)). The studies are retrospective in the sense that they were performed to support a regulatory submission for a device already developed, not as a prospective clinical trial. There is no mention of country of origin for the data beyond the applicant's location (Bedford, Massachusetts).

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

This question is not applicable to the type of validation described. Sterilization validation and material property testing rely on standardized laboratory protocols and measurements, not expert consensus or ground truth derived from clinical experts.

4. Adjudication method for the test set

This question is not applicable. Adjudication methods (like 2+1, 3+1) are typically used for interpreting ambiguous clinical imaging or data by multiple experts. Such a process is not part of sterilization validation or material property testing.

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

This question is not applicable. The device described (ConforMIS iTotal CR KRS) is a knee replacement system, which is an implantable medical device, not an AI or diagnostic application. Therefore, MRMC studies involving human readers and AI assistance are irrelevant.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done

This question is not applicable, as the device is a physical knee implant, not an algorithm or AI system.

7. The type of ground truth used

For sterilization validation:

• Sterility: The "ground truth" for sterility is established by microbiological testing (e.g., bioburden, sterility testing) following international standards, demonstrating the inactivation of microbial populations to the specified SAL.
• EO Residuals: Chemical analysis (analytical chemistry methods) to measure residual levels against predefined safety limits.
• Material Properties: Standardized mechanical, chemical, and material characterization tests (e.g., tensile strength, wear resistance, chemical composition) to compare pre- and post-sterilization properties against specifications.
• Non-pyrogenicity: The LAL (Limulus Amebocyte Lysate) test method, which quantitatively measures endotoxin levels.

8. The sample size for the training set

This question is not applicable, as the device is not an AI/machine learning system that requires a training set.

9. How the ground truth for the training set was established

This question is not applicable.

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