(26 days)
The Hoffmann® II Compact™ MRI components are intended to be used with the Half Pins or Transfixing Pins of the Hoffmann® External Fixation System and the components of the Hoffmann® II External Fixation System. It is intended to be used in the stabilization of open and/or unstable fractures and where soft tissue injury may preclude the use of other fracture treatments such as IM rodding, casting, and other means of internal fixation.
This Special 510(k) submission is intended to address modifications to the predicate Hoffmann® II Compact "External Fixation Systems to include MRI conditional components for use in Magnetic Resonance Imaging (MRI) procedures under predetermined conditions
The provided document is a 510(k) summary for the Hoffmann® II Compact™ MRI External Fixation System, which describes modifications to an existing device to include MRI conditional components. This type of regulatory filing focuses on demonstrating substantial equivalence to a predicate device, primarily through mechanical and MRI safety testing, rather than a clinical study evaluating diagnostic accuracy or reader performance with AI.
Therefore, many of the requested items (e.g., sample size for test/training sets, number of experts, adjudication methods, MRMC studies, standalone performance with AI, type of ground truth for diagnostic accuracy) are not applicable or cannot be extracted from this document as it pertains to a physical medical device (an external fixation system) and not a diagnostic AI algorithm.
However, I can extract information related to the acceptance criteria for the device's MRI compatibility and its demonstrated performance.
Acceptance Criteria and Device Performance for MRI Safety
| Acceptance Criteria Category | Acceptance Criteria | Reported Device Performance |
|---|---|---|
| Mechanical Properties (Substantial Equivalence) | The modified components must demonstrate comparable mechanical properties to the predicate Hoffmann® II Compact™ External Fixation System. | "Mechanical testing demonstrated comparable mechanical properties to the predicate components." (The document does not detail specific numerical targets or results for mechanical properties, only that they were comparable). |
| MRI Safety (Conditional Use) | The modified components must be demonstrated to be safely usable in MRI diagnostic procedures under predetermined conditions. This typically involves assessing: |
- Magnetic Field Interaction (MR Compatibility): Evaluation of attractive or torsional forces in the strong static magnetic field.
- RF-induced Heating: Assessment of temperature increase due to radiofrequency (RF) fields during MRI.
- Artifacts: Evaluation of image distortion caused by the device during MRI. | "testing in a Magnetic Resonance Environment established that the components could be safely used in MRI diagnostic procedures under predetermined conditions." (The document states that the components were found to be MRI conditional, meaning they can be used safely under specific conditions. It does not provide the specific numerical results of the phantom or in-vitro tests conducted to define these conditions, such as the exact static field strength, SAR limits, or temperature rise observed, but implies these were successfully quantified and met relevant standards for MRI-conditional labeling). |
Study Information (as applicable to a physical device modification for MRI compatibility):
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Sample size used for the test set and the data provenance:
- Test Set Sample Size: Not applicable in the context of diagnostic performance testing for an AI. For MRI compatibility testing, the "sample size" would refer to the number of device components tested. The document does not specify the exact number of components or systems tested, but it implies comprehensive testing was performed ("Mechanical testing demonstrated..." and "testing in a Magnetic Resonance Environment established...").
- Data Provenance: The testing was presumably conducted in a laboratory setting by the manufacturer (Howmedica Osteonics Corp.) to assess the device's physical properties and MRI interaction. This would be considered "prospective" testing from the perspective of regulatory submission, as it was performed specifically for this modification and submission. "Country of origin" for data is not explicitly mentioned but typically relates to the testing facilities which, for a US-based company, would likely be in the US or affiliated international labs.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts: Not applicable. This device is an external fixation system, not a diagnostic tool requiring expert interpretation of images or clinical outcomes for its primary function or MRI compatibility. The "ground truth" for MRI compatibility is established through standardized physical measurements in an MRI environment performed by qualified engineers and technicians.
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Adjudication method for the test set: Not applicable. This concept pertains to resolving discrepancies in expert interpretations, which is not relevant for physical device testing concerning mechanical properties or MRI safety.
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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 study type is for evaluating diagnostic AI, not an external fixation system.
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If a standalone (i.e. algorithm only without human-in-the-loop performance) was done: Not applicable. This concept is for diagnostic AI, not an external fixation system.
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The type of ground truth used:
- For mechanical properties, the ground truth is established through engineering standards and measurements (e.g., tensile strength, fatigue life) compared against the predicate device's known performance.
- For MRI safety, the ground truth is established through standardized phantom or in-vitro tests that measure force, torque, temperature rise, and artifact size in controlled MRI environments, adhering to standards like ASTM F2052, F2119, F2182 (or their equivalents at the time).
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The sample size for the training set: Not applicable. This notion applies to machine learning algorithms, not to physical device testing for regulatory clearance based on substantial equivalence.
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How the ground truth for the training set was established: Not applicable for the same reasons as above.
§ 888.3030 Single/multiple component metallic bone fixation appliances and accessories.
(a)
Identification. Single/multiple component metallic bone fixation appliances and accessories are devices intended to be implanted consisting of one or more metallic components and their metallic fasteners. The devices contain a plate, a nail/plate combination, or a blade/plate combination that are made of alloys, such as cobalt-chromium-molybdenum, stainless steel, and titanium, that are intended to be held in position with fasteners, such as screws and nails, or bolts, nuts, and washers. These devices are used for fixation of fractures of the proximal or distal end of long bones, such as intracapsular, intertrochanteric, intercervical, supracondylar, or condylar fractures of the femur; for fusion of a joint; or for surgical procedures that involve cutting a bone. The devices may be implanted or attached through the skin so that a pulling force (traction) may be applied to the skeletal system.(b)
Classification. Class II.