(90 days)
The subject Legion Stems with Holes are intended to be used with femoral and tibial components of the Legion Revision Knee System.
The Revision Knee System Components are indicated for:
- Rheumatoid arthritis.
- Post-traumatic arthritis, osteoarthritis, or degenerative arthritis in older patients whose age, weight, and activity levels are compatible with an adequate long-term result.
- Failed osteotomies, unicompartmental replacement, or total knee replacement.
- The constrained knee systems are designed for use in patients in primary and revision surgery, where the posterior cruciate ligament and one on both of the collateral ligaments (i.e. medial collateral and/or lateral collateral ligament) are absent or incompetent.
The subject stems are revision stems manufactured from titanium alloy which feature distal fixation holes. The stems will be available in a variety of lengths and diameters, and they will be used in conjunction with currently marketed femoral and tibial components of the Legion Revision Knee System.
The provided text is a 510(k) summary for the Smith & Nephew Legion Stems with Holes. This document focuses on demonstrating substantial equivalence to predicate devices for a knee prosthesis component, not on presenting a study with acceptance criteria for device performance as would be expected for an AI/ML medical device.
Therefore, the information required for your request, such as a table of acceptance criteria, device performance, sample sizes, expert qualifications, ground truth establishment, or specific study types like MRMC or standalone performance, is not present in the provided text.
The closest information available that might relate to "acceptance criteria" is the Indications for Use, which defines the patient populations and conditions for which the device is intended. The device's "performance" in this context is implicitly considered acceptable through its substantial equivalence to existing, legally marketed devices.
Here's how I can address your request based only on the provided text, highlighting what is missing:
1. A table of acceptance criteria and the reported device performance
| Acceptance Criteria (Implied) | Reported Device Performance (Implied) |
|---|---|
| Substantial equivalence to predicate devices in Indications for Use, material, method of manufacture, and basic design principles. | The device is substantially equivalent to the predicate devices (Smith & Nephew Legion Press-Fit Stem and TriGen Knee Nail) in the specified aspects. |
| Distal fixation mechanism is substantially equivalent to the TriGen Knee Nail. | The distal fixation mechanism is substantially equivalent to the TriGen Knee Nail. |
- Missing: Specific numerical performance metrics (e.g., accuracy, sensitivity, specificity, mechanical strength tolerances) that would be common for AI/ML or other performance-based device studies are not available in this document. The "performance" here is regulatory compliance through substantial equivalence.
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
- Missing: The document does not describe a "test set" in the context of device performance evaluation (e.g., clinical study data). The substantial equivalence determination is based on comparative analysis of device characteristics and intended use, not clinical trial data with a test set.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
- Missing: Not applicable for this type of submission. There is no "test set" in the sense of clinical images or patient data requiring expert ground truth.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
- Missing: Not applicable for this type of submission.
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
- Missing: Not applicable. This is not an AI/ML device, and no MRMC study is mentioned.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Missing: Not applicable. This is not an AI/ML device.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
- Missing: Not applicable. The "ground truth" for this submission is regulatory compliance based on the documented characteristics of the device and its predicate.
8. The sample size for the training set
- Missing: Not applicable. This is not an AI/ML device, and no "training set" is mentioned.
9. How the ground truth for the training set was established
- Missing: Not applicable. This is not an AI/ML device, and no training set is mentioned.
Summary based on the provided text:
The 510(k) submission for the Legion Stems with Holes primarily relies on demonstrating substantial equivalence to predicate devices (Smith & Nephew Legion Press-Fit Stem and TriGen Knee Nail) rather than presenting data from a clinical performance study with acceptance criteria. The "proof" is the detailed comparison of the new device's features (such as indications for use, material, method of manufacture, and basic design principles, including the distal fixation mechanism) to those of the already-marketed predicate devices. The FDA's issuance of the 510(k) clearance signifies agreement with this claim of substantial equivalence.
§ 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.