(89 days)
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 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, 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 Posterior Stabilized Retaining Knee Replacement System (hereafter referred to as the "iTotal PS KRS") is a patient specific tricompartmental faceted, cruciate sacrificing knee replacement system. The iTotal PS KRS is a semi-constrained cemented knee implant which consists of a femoral, tibial and patellar component.
The system is intended to treat patients who are candidates for total knee arthroplasty where the collateral ligaments are intact. Use of the iTotal PS KRS is usually based on surgeon preference, but it may be also used when total knee replacement is indicated and the posterior cruciate ligament is compromised, absent, or surgically excised.
Using patient imaging (CT scan) 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 a polyethylene insert that is manufactured from ultra-high molecular weight polyethylene (UHMWPE). The patellar component is manufactured from either UHMWPE or from a highly cross-linked Vitamin E infused polyethylene (iPoly XE™).
For user convenience, and similar to the predicate (iTotal CR KRS), ancillary orthopedic manual surgical instruments designed for use with the iTotal PS 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 intended use and function of the patient specific ancillary instruments remain similar to those described in the predicate 510ks i.e. K131467 & K131019. There are only a few differences such as the addition of jigs to guide the bone cutting for the femoral box, the introduction of a full thickness flexion spacer to help assess joint space, and the insert trials that are made to match the tibial insert with the spine feature.
The provided text describes the 510(k) summary for the ConforMIS iTotal Posterior Stabilized Knee Replacement System (iTotal PS KRS). It details the device, its intended use, and the studies conducted to establish its substantial equivalence to predicate devices.
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria for the iTotal PS KRS were not explicitly provided as numerical targets. Instead, the study's goal was to demonstrate substantial equivalence to predicate devices through functional testing. The "reported device performance" is the conclusion that the device's performance in these non-clinical tests was comparable to the predicate devices, thereby meeting the implicit acceptance criteria of being "safe and substantially equivalent."
| Acceptance Criteria (Implicit) | Reported Device Performance |
|---|---|
| Functional equivalence to predicate devices in mechanical and performance tests. | All non-clinical laboratory tests demonstrated that the device is substantially equivalent to the predicate devices and is safe for its intended use. |
2. Sample Size Used for the Test Set and Data Provenance
The document details non-clinical laboratory tests, meaning physical and mechanical tests performed on the device components, not on human patients. Therefore, terms like "test set," "country of origin," and "retrospective or prospective" do not directly apply in the typical medical device AI/software context.
- Sample Size for Test Set: Not explicitly stated as a number of "samples" in a clinical sense. The tests involve multiple specimens of the device components (e.g., femoral components, tibial trays, inserts) subjected to various mechanical loads and conditions. The specific number of specimens per test is not provided in this summary.
- Data Provenance: N/A, as these are non-clinical, laboratory-based tests of physical components, not patient data.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications of Those Experts
N/A. This information is relevant for studies involving human assessment or interpretation (e.g., image review by radiologists). For the mechanical and functional testing described, "experts" in establishing ground truth would refer to engineers and technicians conducting the tests and interpreting the results according to established engineering and regulatory standards, not clinical experts.
4. Adjudication Method for the Test Set
N/A. Adjudication methods (like 2+1, 3+1) are used to resolve disagreements among human reviewers (e.g., radiologists) when establishing ground truth from patient data. This is not applicable to the non-clinical laboratory testing described.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No. An MRMC comparative effectiveness study involves human readers assessing cases with and without AI assistance to measure the AI's impact on human performance. The studies mentioned here are entirely non-clinical laboratory tests to determine physical and mechanical equivalence, not human-in-the-loop performance studies.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
The device is a physical knee replacement system and patient-specific surgical instruments, not an AI algorithm. Therefore, "standalone algorithm performance" (without human-in-the-loop) is not applicable.
The closest analogy to "standalone performance" in this context would be the "Software verification and validation testing" mentioned, which assesses the performance of the software used to design the patient-specific implants. However, no details are provided about the outcome or methodology of this software testing other than its inclusion in the list of non-clinical tests.
7. The Type of Ground Truth Used
The "ground truth" for the non-clinical tests would be the established engineering and biomechanical properties, performance characteristics, and material specifications required by the FDA guidance document and by existing predicate devices.
- Type of Ground Truth: Engineering and biomechanical standards, material specifications, and performance characteristics (e.g., fatigue life, contact stress, constraint) of predicate devices as set forth in "The FDA Guidance Class II Special Controls Guidance Document: Knee Joint Patellofemorotibial and Femorotibial Metal/Polymer Porous-Coated Uncemented Prostheses; Guidance for Industry and FDA, issued January 16, 2003."
8. The Sample Size for the Training Set
N/A. This concept is for machine learning models. The device is a physical implant system, not an AI model trained on data. The software used to design the patient-specific implants would likely be developed and validated rather than "trained" in the machine learning sense. The summary provides no information on the development or validation of this software, or any "training set."
9. How the Ground Truth for the Training Set Was Established
N/A, for the reasons mentioned in 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.