(388 days)
The Symmetric™ Total Knee Augments consist of single use components intended for attachment to the Symmetric Total Knee implants during total knee arthroplasty with the following indications.
- Osteoarthritis
- Rheumatoid Arthritis
- Traumatic Arthritis or correction of posttraumatic joint deformity
- Where the use of a more conservative procedure has failed or is unacceptable.
All components are for cemented use.
Additional indications for use:
Whenever a cone is used, a revision stem is to be used as well.
The Symmetric™ Total Knee Augments are intended to complement the Symmetric Total Knee System. The system consists of metallic wedges, stems, cones, sleeves, and offset trunnions that can be used with the Symmetric Total Knee System to provide increased bone contact and support during total knee arthroplasty when more conservative methods have failed.
The FEMORAL WEDGES are designed to fill voids remaining in the peripheral bone stock after the removal of diseased and damaged bone, and to provide indirect bone support for the femoral component. These wedges are made of Titanium 6Al-4V and have grit blasted surfaces where they are designed to be cemented to Symmetric Total Knee femoral implants and titanium plasma sprayed surfaces to provide good cemented fixation to bone. The components are available for the distal and posterior surfaces individually or combined. These wedges are symmetric so they will work on the medial or lateral side of either knee.
The TIBIAL WEDGES are designed to fill voids remaining in the peripheral bone stock after the removal of diseased and damaged bone, and to provide indirect bone support for the tibial component. These wedges are made of Titanium 6A1-4V and are designed for cemented fixation to Symmetric Total Knee tibial implants. The titanium plasma sprayed surfaces provide increased fixation for bone cement. The components are available in flat and wedged designs, and are able to be used on the medial or lateral side of the symmetric trays.
The TIBIAL and FEMORAL Cones are designed to fill voids remaining in the central bone stock after the removal of diseased and damaged bone, and to provide indirect bone support for the femoral or tibial component. These cones are symmetrically designed components designed for cemented fixation around the trunnion or revision stem of a Symmetric total knee implant. The cones are made of Titanium 6Al-4V and are internally grit blasted for cement fixation against the implant and externally plasma sprayed to provide increased cemented fixation to bone.
The OFFSET TRUNNIONS are designed to be attached to the trunnion of the femoral or tibial component utilizing a Morse Taper, and then has a Morse Taper of its own to receive a revision stem. The offset stems are made of Titanium 6A1-4V, and are designed to provide adjustments in stem position with respect to the primary implants trunnion, allowing the stem to line up with the patient's medullary canal more effectively.
The COATED AND PARTIALLY COATED REVISION STEMS are designed to be attached to the trunnion of the femoral or tibial component utilizing the Morse Taper. The stems are made of Titanium 6Al-4V and are titanium plasma sprayed to provide increased fixation.
The RECTANGULAR REVISION STEMS are designed to be attached to the trunnion of the femoral or tibial component utilizing the Morse Taper. The stems are made of Titanium 6AI-4V and are available in non-coated and titanium plasma spray coated styles. The rectangular shape is designed to provide cortical bone support while reducing cancellous bone loss.
Here's an analysis of the provided text regarding the Symmetric™ Total Knee Augments and its associated study, structured according to your requested points:
The provided text describes a 510(k) premarket notification for the Symmetric™ Total Knee Augments, a medical device. It focuses on demonstrating substantial equivalence to predicate devices, rather than directly proving the device meets an explicit set of acceptance criteria through a specific performance study in the way a diagnostic AI might. The "performance" here refers to the physical and material characteristics of the implants and their intended use.
1. A table of acceptance criteria and the reported device performance
The concept of "acceptance criteria" and "reported device performance" as typically applied to AI or diagnostic devices (e.g., sensitivity, specificity, accuracy thresholds) is not directly applicable here. This document is a 510(k) summary for a medical implant, which demonstrates substantial equivalence to existing devices rather than meeting a specific performance metric against a gold standard in a clinical study.
Instead, the "acceptance criteria" are implied by the similarities to predicate devices and the successful completion of non-clinical (mechanical) testing as outlined to the FDA for regulatory clearance. The "device performance" is therefore the demonstration of these similarities and the satisfactory results of the engineering tests.
| Acceptance Criteria (Implied by Predicate & Standards) | Reported Device Performance (Symmetric Total Knee Augments) |
|---|---|
| Intended Use: Cemented application in total knee arthroplasty for osteoarthritis, rheumatoid arthritis, traumatic arthritis, or post-traumatic deformity where conservative methods failed. Whenever a cone is used, a revision stem is also used. | Meets: Same intended use as predicate devices. All components for cemented use. |
| Material Composition (e.g., Femoral Wedges): Titanium 6Al-4V, Titanium Plasma Spray coating. | Meets: Titanium 6Al-4V, Titanium Plasma Spray (ASTM F1580) for coatings. |
| Fixation Method (e.g., Femoral Wedges): Cemented to implant. | Meets: Cemented to implant. |
| Dimensional Characteristics (e.g., Femoral Wedges Thickness): Similar to predicate devices (e.g., 5-10mm posterior, 5-15mm distal). | Meets: Thickness characteristics are comparable to predicate devices. |
| Mechanical Performance: Withstand compressive fatigue, static, and torsional loads; proper assembly/disassembly. | Meets: Non-clinical testing included compressive fatigue and static testing, torsional testing, and assembly/disassembly testing of the offset trunnion with a tray and stem. Results stated to be "substantially equivalent to or better than those of at least one predicate device." |
| Compliance with Material Standards: ASTM F1472 (Titanium), ASTM F1580 (Plasma Spray Coating). | Meets: All components listed comply with ASTM F1472 and ASTM F1580 where applicable. |
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
- Test Set Sample Size: Not applicable in the context of a clinical test set as for diagnostic devices. The "testing" refers to mechanical and material characterization. The document does not specify sample sizes (e.g., how many wedges were fatigue-tested) but refers to "a writeup of the testing completed for this 510(k) is included in Section 18."
- Data Provenance: The testing is non-clinical, likely conducted in a laboratory setting, not geographically specific patient data.
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)
Not applicable. This device is a mechanical implant. Ground truth is established through engineering design specifications, material standards (ASTM), and mechanical testing protocols, not expert consensus on medical images or patient outcomes.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
Not applicable. Adjudication methods like 2+1 or 3+1 are used for establishing ground truth in clinical or diagnostic studies. This is a non-clinical, engineering-focused 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
Not applicable. This is a knee implant, not an AI or diagnostic tool that assists human readers.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Not applicable. This is a knee implant.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
The "ground truth" for this type of device is material specifications (ASTM standards), engineering design principles, and mechanical test results that demonstrate structural integrity and performance equivalent to or better than predicate devices. There is no "ground truth" in the clinical sense (e.g., pathology, outcomes data) for this 510(k) process as "No clinical data was utilized for the basis of substantial equivalence."
8. The sample size for the training set
Not applicable. This device does not involve a training set as it is not an AI or machine learning model.
9. How the ground truth for the training set was established
Not applicable. This device does not involve a training set.
§ 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.