(271 days)
Smith & Nephew's Patient Matched Cutting Blocks are intended to be used as patient-specific surgical instrumentation to assist in the positioning of total knee replacement components intra-operatively and in guiding the marking of bone before cutting provided that anatomic landmarks necessary for alignment and positioning of the implant are identifiable on patient imaging scans.
The Patient Matched Cutting Blocks are intended for use with the following existing Smith & Nephew, Inc. knee systems and their cleared indications for use:
- · Genesis II Knee System
- · Legion Knee System
- · Journey BCS Knee System
- · Journey II Knee System
The Patient Matched Cutting Blocks are intended for single use only.
The Patient Matched Cutting Blocks were previously cleared for market via premarket notification K082358. Subject of this premarket notification are modifications to the software components used to design and manufacture the Patient Matched Cutting Blocks. The Patient Matched Cutting Blocks are designed and manufactured from patient imaging data (MRJ, X-Ray).
Here's a breakdown of the requested information based on the provided text:
Acceptance Criteria and Device Performance Study
1. Table of Acceptance Criteria and Reported Device Performance
| Performance Metric | Acceptance Criteria (Stated or Implied) | Reported Device Performance |
|---|---|---|
| Resection Depth | Equivalent to conventional instrumentation OR within clinically acceptable parameters. | The patient-matched cutting blocks designed using the case processing applications perform equivalent to conventional instrumentation or within clinically acceptable parameters. |
| Coronal Alignment (Varus/Valgus) | Equivalent to conventional instrumentation OR within clinically acceptable parameters. | The patient-matched cutting blocks designed using the case processing applications perform equivalent to conventional instrumentation or within clinically acceptable parameters. |
| Rotation | Equivalent to conventional instrumentation OR within clinically acceptable parameters. | The patient-matched cutting blocks designed using the case processing applications perform equivalent to conventional instrumentation or within clinically acceptable parameters. |
| Tibial Posterior Slope | Equivalent to conventional instrumentation OR within clinically acceptable parameters. | The patient-matched cutting blocks designed using the case processing applications perform equivalent to conventional instrumentation or within clinically acceptable parameters. |
| Software Performance | Perform as intended, with no new issues related to safety and effectiveness. | A review of software verification and validation testing demonstrated that there are no new issues related to the safety and effectiveness of the subject device and the software will perform as intended. |
2. Sample Size Used for the Test Set and Data Provenance
The provided text states that a cadaveric assessment was conducted. However, it does not specify the sample size (i.e., number of cadavers or knees tested) for this assessment.
Regarding data provenance, the test data comes from a cadaveric study. The country of origin of the data is not explicitly stated, but the submitting company is Smith & Nephew, Inc., located in Memphis, Tennessee, USA, suggesting the study was likely conducted in the US. The study is prospective in nature, as it involves physical testing of the device.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Their Qualifications
The document does not specify the number of experts used or their qualifications for establishing ground truth in the cadaveric assessment. It only mentions the "cadaveric assessment" and its results.
4. Adjudication Method for the Test Set
The document does not describe any adjudication method for the test set. Given the nature of a cadaveric assessment for physical measurements (resection depth, alignment, rotation, slope), it's possible that measurements were taken directly by researchers or using precise instruments, rather than relying on expert consensus and adjudication in the typical sense applied to image interpretation.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size
No. The document does not mention a Multi-Reader Multi-Case (MRMC) comparative effectiveness study. The study conducted was a cadaveric assessment comparing the patient-matched cutting blocks to conventional instrumentation. Therefore, there is no reported effect size of how much human readers improve with AI vs. without AI assistance. The device in question is a physical cutting block, not an AI for image interpretation.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
The device itself is a physical patient-matched cutting block, which inherently requires human-in-the-loop for its application during surgery. The software components used to design these blocks were verified and validated. While this software operates "standalone" in its design function, the overall device performance (the cutting blocks) is evaluated in the context of their use by a surgeon. The cadaveric assessment tests the performance of the cutting blocks themselves, not just the underlying design software in isolation from their physical use. Hence, a standalone algorithmic performance of the cutting block itself is not applicable in the same way it would be for an AI diagnostic tool. However, the software validation for the design process demonstrates its standalone functionality in generating the block designs.
7. The Type of Ground Truth Used
For the cadaveric assessment, the ground truth was likely established through direct physical measurement of the resections, alignments, rotations, and slopes achieved by using the cutting blocks, and comparison to the known expected values or to the results from conventional instrumentation. This would fall under objective physical measurements rather than pathology or expert consensus on interpretation.
8. The Sample Size for the Training Set
The document states that the Patient Matched Cutting Blocks are designed and manufactured from "patient imaging data (MRJ, X-Ray)." This indicates that patient imaging data is used to design each individual cutting block for each patient. This is not a "training set" in the machine learning sense, but rather the input data for the design process.
If we interpret "training set" as the data used to develop and refine the software components that design these blocks, the document does not provide a specific sample size for such a development or training set. It only mentions that software verification and validation testing was completed.
9. How the Ground Truth for the Training Set Was Established
Given that the "training set" refers to patient-specific imaging data used for design rather than a dataset for machine learning algorithm training, the concept of "ground truth" for this data is inherent in the patient's anatomy as captured by the imaging. The software uses these images to identify "anatomic landmarks necessary for alignment and positioning of the implant." Therefore, the "ground truth" for the input data is the patient's anatomical features as depicted in the imaging scans (MRJ, X-Ray). The accuracy of these images and the subsequent identification of landmarks by the software determine the "ground truth" for the design process. The document does not detail how the accuracy of landmark identification from these images was established or verified during the software development process, beyond general software validation.
§ 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.