(121 days)
The CAS PSI Knee System is indicated as an orthopedic instrument system to assist in the positioning of knee replacement components. It involves surgical planning software used pre-operatively to plan the surgical placement of the components on the basis of provided patient radiological images with identifiable placement anatomical landmarks, and surgical instrument components that include patient specific or customized guides fabricated on the basis of the surgical plan to precisely reference the placement of the implant components intra-operatively per the surgical plan.
The CAS PSI Knee System is to be used with the following fixed bearing knee replacement systems in accordance with their indications and contraindications: NexGen CR, NexGen CR-Flex, Nexgen CR-Flex Gender, Nexgen LPS, Nexgen LPS-Flex, Nexgen LPS-Flex Gender, Persona CR, and Persona PS.
The patient specific guide components are intended for single-use only.
The CAS PSI Knee is an orthopedic instrument system indicated to assist in the positioning of knee replacement components. It involves surgical planning software used pre-operatively, and surgical instrument components that include patient specific guides to precisely align and position the implant components intra-operatively relative to each patient's anatomical features per the surgical plan. The surgical planning software allows the review of patient joint models determined from radiological images upon which the surgical placement of the implant components is adjusted per anatomical landmarks. The patient specific guides are fabricated per the patient models to fit each patient's anatomy with features that set the relative placement of the implant components per the surgical plan. The system is compatible with given implant systems per its indications for use.
The provided document describes the CAS PSI Knee System, an orthopedic instrument system designed to assist in the positioning of knee replacement components. It includes surgical planning software and patient-specific guides.
Here's an analysis of the acceptance criteria and study information:
1. Table of Acceptance Criteria and Reported Device Performance:
The document does not explicitly state quantitative acceptance criteria (e.g., "accuracy must be within X mm" or "reproducibility must be within Y degrees"). Instead, it broadly describes the types of tests conducted and concludes with a statement of satisfactory performance for its intended use.
| Acceptance Criteria Category | Specific Criteria (Implicit/General) | Reported Device Performance |
|---|---|---|
| Software System Tests | No hazardous anomalies present. | "Performed to ensure that no hazardous anomalies were present in the system software components. They consisted of testing software features and functionalities in correspondence to software design requirements." (Implies requirements were met.) |
| Software Performance Tests | Reproducibility and accuracy of algorithms (model meshing, segmentation, landmark assignment, planning, jig creation). | "Tests were performed to verify the reproducibility and accuracy of the software system algorithms. These included the accuracy and reproducibility of the software tools, the model meshing and segmentation methods, the assignment of surgical landmarks, the planning method, and the jig creation algorithms." (Implies verification of both reproducibility and accuracy.) |
| Guide Mechanical Resistance Tests | Mechanical performance (resistance to use/drop breakage, debris generation, aging stability, sterilization, extreme shipping). | "Tests were performed to verify the mechanical performance of the guides including resistance to use or drop breakage, debris generation, aging stability, sterilization, and extreme shipping conditions." (Implies successful verification of these mechanical properties.) |
| Full System Validation Tests | Overall system performance in terms of usage and instrument ergonomics. | "Full use simulations tests using cadaver specimens or sawbones were performed by multiple surgeons to verify and validate the overall system performance in terms of system usage and instrument ergonomics. The results demonstrated satisfactory performance per the intended use." (Indicates satisfactory performance as judged by multiple surgeons during simulations.) |
The overall conclusion is that "The information and data provided ... established that the CAS PSI Knee System is substantially equivalent to the predicates." This is the ultimate "acceptance" for 510(k) clearance, rather than meeting specific quantitative performance thresholds.
2. Sample Size for the Test Set and Data Provenance:
The document mentions "full use simulations tests using cadaver specimens or sawbones."
- Sample Size: The exact number of "cadaver specimens or sawbones" is not specified. It refers to generic plural forms.
- Data Provenance: The document does not specify the country of origin. The data is presented as prospective simulation tests conducted for validation.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications:
- Number of Experts: "multiple surgeons." The exact number is not specified.
- Qualifications of Experts: They are described as "surgeons," implying medical doctors specializing in surgery, likely orthopedic surgeons given the context of knee replacement. No specific experience level (e.g., "10 years of experience") is provided.
4. Adjudication Method for the Test Set:
The document mentions "Full use simulations tests... were performed by multiple surgeons to verify and validate the overall system performance..." It states that "The results demonstrated satisfactory performance per the intended use." This suggests a consensus-based or qualitative evaluation by the surgeons, but no specific adjudication method (e.g., 2+1, 3+1, none) is detailed. The assessment of "satisfactory performance" is the reported outcome.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done:
- No, an MRMC comparative effectiveness study was NOT explicitly stated or described in the provided text. The "full system validation tests" involved "multiple surgeons" but focused on verifying the system's performance and ergonomics, rather than comparing human reader performance with and without AI assistance or quantifying an effect size of improvement.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Yes, standalone performance was assessed for the software components. The "Software Performance Tests" specifically focused on verifying "the reproducibility and accuracy of the software system algorithms. These included the accuracy and reproducibility of the software tools, the model meshing and segmentation methods, the assignment of surgical landmarks, the planning method, and the jig creation algorithms." This refers to the algorithm's performance without direct human intervention in the execution of the plan.
7. The Type of Ground Truth Used:
- For the "Software Performance Tests," the ground truth likely involved pre-defined anatomical landmarks and surgical plans against which the algorithm's output (meshing, segmentation, landmark assignment, planning, jig creation) was compared for accuracy and reproducibility.
- For the "Full System Validation Tests," the ground truth was effectively expert assessment/consensus ("satisfactory performance per the intended use") by multiple surgeons observing the system's usage and instrument ergonomics in simulation. It's an assessment of whether the system achieved the intended surgical outcome or allowed surgeons to achieve it.
8. The Sample Size for the Training Set:
The document does not provide information on the sample size used for the training set of the software. The software's capabilities are described (modeling patient anatomy from MRI scans, identifying landmarks, planning implant placement), but not the data used to develop or train these capabilities.
9. How the Ground Truth for the Training Set Was Established:
The document does not provide information on how the ground truth for the training set was established.
§ 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.