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510(k) Data Aggregation
(51 days)
The Stryker VariAx 2 Wrist Fusion System is indicated for wrist arthrodesis and fixation of fractures in patients with wrist arthritis or fractures of other small bones of the carpus. Specific indications include:
- Post-traumatic arthritis of the joints of the wrist .
- Rheumatoid wrist deformities requiring restoration ●
- Complex carpal instability ●
- Post-septic arthritis of the wrist ●
- Severe unremitting wrist pain related to motion
- Brachial plexus nerve palsies
- o Tumor resection
- Spastic deformities
VariAx 2 Wrist Fusion System is a fixation device that consists of plates with different design (standard bend, short bend, and straight) manufactured from Commercially Pure Titanium Grade 2 (ASTM F67). The plates will be available sterile and non-sterile. VariAx 2 Wrist Fusion System will be used with locking and non-locking screws (2.3mm, 2.7 and 3.5mm) previously cleared in K040022 (Stryker® Leibinger Universal Distal Radius System), K073527 (VariAx™ Elbow System), K080667 (VariAx™ Distal Radius Torx Screws), and K140769 (VariAx 2 System). VariAx 2 Wrist Fusion System will be used with new and existing instruments previously cleared in K101056 (VariAx Elbow System), K130009 (VariAx 2 Compression Plating System), and K140769 (VariAx 2 System).
This document describes a 510(k) premarket notification for the Stryker VariAx 2 Wrist Fusion System, a metallic bone fixation appliance. The FDA determined the device is substantially equivalent to legally marketed predicate devices.
Here's an analysis based on your requested information:
1. A table of acceptance criteria and the reported device performance
Since this is a 510(k) submission based on substantial equivalence, the "acceptance criteria" are implied by the performance of the predicate device. The goal is to demonstrate that the new device is as safe and effective as the predicate.
| Acceptance Criteria (Implied by Predicate) | Reported Device Performance (VariAx 2 Wrist Fusion System) |
|---|---|
| Mechanical performance, specifically fatigue strength (as per ASTM F382-14) | Demonstrated to be equivalent in mechanical performance to the predicate device, the Synthes Wrist Fusion Plates (K000558). Testing included Dynamic Cantilever Bending Testing (fatigue strength). |
| Intended Use | The Stryker VariAx 2 Wrist Fusion System has the same intended use as the predicate device: indicated for wrist arthrodesis and fixation of fractures in patients with wrist arthritis or fractures of other small bones of the carpus. Specific indications are also listed and are consistent with similar devices. |
| Material | The plates are manufactured from Commercially Pure Titanium Grade 2 (ASTM F67), which is a common material for bone implants and likely consistent with the predicate or other similar devices. |
| Design | The device consists of plates with different designs (standard bend, short bend, and straight) and is used with locking and non-locking screws (2.3mm, 2.7mm, and 3.5mm) and new and existing instruments. Device comparison demonstrated substantial equivalence to the Synthes Wrist Fusion Plates (K000558) in regards to design. |
| Operational Principles | Device comparison demonstrated substantial equivalence to the Synthes Wrist Fusion Plates (K000558) in regards to operational principles. |
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
The document states: "Non-clinical laboratory testing was performed on the worst case subject plates to determine substantial equivalence."
- Sample Size: The exact sample size for the mechanical testing is not specified in this document. It refers to "worst case subject plates," implying a representative selection, but the number is not given.
- Data Provenance: The testing was "non-clinical laboratory testing." The country of origin of the data is not specified, but the sponsor is Stryker Trauma AG, located in Switzerland, and the contact person is in Germany. The testing itself would likely have occurred in a laboratory setting associated with the manufacturer or a contracted testing facility. It is prospective in nature, as it's testing performed specifically for this submission.
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)
This device is a mechanical implant, not an AI/diagnostic device. As such, "ground truth" in the context of expert consensus for diagnostic interpretation is not applicable. The "ground truth" for the non-clinical testing is established by the ASTM F382-14 standard for metallic bone plates, which defines the acceptable mechanical properties. The "experts" in this context would be the engineers and technicians performing and interpreting the mechanical tests according to the standard. Their qualifications are not specified but would be in mechanical engineering or materials science.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
Adjudication methods like 2+1 or 3+1 are typically for clinical studies involving human interpretation or subjective endpoints. For non-clinical mechanical testing, there is no adjudication method mentioned or typically required in the same sense. The results are quantitative measurements against an established standard (ASTM F382-14). Discrepancies would be handled through repeat testing or calibration, not expert consensus.
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
No MRMC study was done. This is a hardware implant device, not an AI or diagnostic software.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Not applicable. This section is for AI/software devices. The device is a physical bone fixation system.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
For the non-clinical mechanical testing, the "ground truth" for evaluating the device's performance is:
- Compliance with the ASTM F382-14 'Standard specification and test method for metallic bone plates'. This standard defines the acceptable mechanical properties, such as fatigue strength.
8. The sample size for the training set
Not applicable. This device is a hardware implant and does not involve AI or machine learning algorithms that require a "training set."
9. How the ground truth for the training set was established
Not applicable. See point 8.
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(75 days)
The Stryker VariAx 2 System is intended for internal bone fixation in adult patients.
The Stryker VariAx 2 System screws, when used in conjunction with VariAx Plating Systems; or used independently in a lag screw technique, are indicated for:
- Internal fracture fixation;
- Osteotomies:
- Revision procedures such as non-unions or mal-unions;
In addition, the following indications are specific to the devices listed below:
- T8 2.4mm Screws & T8 2.0mm Locking Peg: For use in small bones, primarily including the Distal Radius, in the treatment of:
- Compression fractures:
- Intra-articular and extra-articular fractures;
- Displaced fractures;
- Reconstruction procedures;
- T8 2.7mm Screws: For use in small bones, including the Distal Radius as well as the fore, midand hind Foot and Ankle, in the treatment of:
- Intra-articular and extra-articular fractures of the Distal Radius,
- Displaced and compression fractures of the Distal Radius;
- Replantation, joint fusions or arthrodesis and corrective osteotomies in the Foot & Ankle;
- Reconstruction procedures in the Foot & Ankle and Distal Radius:
- T10 3.5mm and T10 2.7mm Screws: For use in the Radius, Ulna, Clavicle, Humerus, Foot and Ankle, Distal Tibia and Fibula, in the treatment of:
- Intra-articular and extra-articular fractures of the Distal Humerus and Proximal Ulna:
- Single, segmental and comminuted fractures;
- Replantation, joint fusions or arthrodesis and corrective osteotomies in the Foot & Ankle:
- Normal bone density or osteopenic bone.
The VariAx 2 System is an internal fixation device consisting of screws and instrumentation that will be used in conjunction with previously cleared VariAx Plating Systems to treat a number of different types of fractures in the radius, ulna, humerus, clavicle, foot, and fibula. These screws can be used in conjunction with said plating systems, or in the case of non-locking screws, may also be used independently using a lag screw technique. The subject components will be available sterile and non-sterile.
The VariAx 2 System is a medical device designed for internal bone fixation. Its acceptance was determined through non-clinical laboratory testing, demonstrating substantial equivalence to previously cleared predicate devices.
1. Acceptance Criteria and Reported Device Performance:
| Test Performed | Acceptance Criteria | Reported Device Performance |
|---|---|---|
| Screw Pull-Out Testing | Performance comparable to predicate devices | Substantially equivalent to predicate devices |
| Screw Shear-Off Testing | Performance comparable to predicate devices | Substantially equivalent to predicate devices |
| Screw Insertion Torque Testing | Performance comparable to predicate devices | Substantially equivalent to predicate devices |
| Static Cantilever Bending of Locking Mechanism | Performance comparable to predicate devices | Substantially equivalent to predicate devices |
| Dynamic Fatigue Plate-Screw Construct Testing | Performance comparable to predicate devices | Substantially equivalent to predicate devices |
Note: The document does not provide specific numerical values for the acceptance criteria or reported performance. The "acceptance criteria" and "reported device performance" are inferred from the statement "Testing demonstrated that the VariAx 2 System is substantially equivalent to the predicate devices currently cleared for marketing."
2. Sample Size and Data Provenance for Test Set:
- Sample Size: The document does not specify the sample size used for each non-clinical test.
- Data Provenance: Not applicable as the testing was non-clinical laboratory testing. The country of origin for the sponsor, Stryker Trauma AG, is Switzerland.
3. Number and Qualifications of Experts for Ground Truth:
Not applicable. The regulatory pathway for this device (510(k)) focuses on substantial equivalence through non-clinical testing for fracture fixation systems, not on human expert assessment for image interpretation or diagnosis. Therefore, no experts were used to establish ground truth in the context of image interpretation.
4. Adjudication Method for Test Set:
Not applicable. This was a non-clinical device testing study, not a clinical study involving human judgment or interpretation requiring adjudication.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
No, a multi-reader multi-case (MRMC) comparative effectiveness study was not performed. The submission explicitly states, "Clinical testing was not required for this submission."
6. Standalone Performance Study:
Yes, in a way. The non-clinical laboratory tests assess the performance of the device components (screws and plate-screw constructs) in isolation, under controlled laboratory conditions, to determine their mechanical properties and functional equivalence to predicate devices. This represents an "algorithm only without human-in-the-loop performance" in the context of a physical device's mechanical integrity.
7. Type of Ground Truth Used:
The ground truth used for proving the device meets acceptance criteria was based on engineering and mechanical performance benchmarks established by predicate devices and recognized industry standards for bone fixation appliances. These benchmarks are inherently quantitative and objective, derived from physical testing.
8. Sample Size for the Training Set:
Not applicable. This device is a physical bone fixation system, not an AI/ML algorithm. Therefore, there is no "training set" in the context of machine learning.
9. How the Ground Truth for the Training Set Was Established:
Not applicable, as there is no training set for this type of medical device submission.
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