Class II Non-Spinal Metallic Bone Screws and Washers - Safety and Performance Based Pathway
This guidance covers Class II non-spinal metallic bone screws and washers intended for orthopedic fracture fixation, osteotomy, or small joint fusion/arthrodesis. It specifically applies to devices made from specific metallic materials (titanium alloys, stainless steel, cobalt-chromium alloys) and excludes mandibular, maxillofacial, cranial, orbital, and spinal applications, as well as devices with complex geometries or unique technological characteristics.
Recommended Actions
- Determine if device falls within scope of guidance
- Select appropriate material conforming to specified ASTM standards
- Conduct mechanical testing (torsional strength, driving torque, axial pullout)
- Perform biocompatibility evaluation or provide rationale for waiver
- Complete sterilization/reprocessing validation as applicable
- Prepare documentation demonstrating conformance to performance criteria
- Consider Pre-Submission if additional testing beyond guidance is needed
- Submit 510(k) using Safety and Performance Based Pathway with required test results and documentation
Key Considerations
Non-clinical testing
- Mechanical bench testing required:
- Torsional strength testing per ASTM F543
- Driving torque testing per ASTM F543
- Axial pullout strength evaluation through engineering analysis
- Specific performance criteria provided for different screw diameters
- Minimum of 5 samples required for testing
Biocompatibility
- Evaluation required for implanted devices with prolonged/permanent contact
- Testing endpoints include cytotoxicity, sensitization, irritation, systemic toxicity, pyrogenicity, genotoxicity, implantation, chronic toxicity, and carcinogenicity
- Testing may be waived if using identical materials and processes as predicate device
Safety
- Sterilization validation required for sterile devices
- Reprocessing validation required for end-user sterilized devices
- Must demonstrate sterility assurance level of 10-6
Other considerations
- Device design must comply with dimensional specifications
- Inner diameter of washers must be larger than screw thread diameter but smaller than screw head
- Material selection must conform to specified ASTM standards
Relevant Guidances
- Safety and Performance Based Pathway for 510k Substantial Equivalence Demonstration
- Use of ISO 10993-1 for Biological Evaluation and Testing of Medical Devices
- Reprocessing Instructions for Reusable Medical Devices and Non-Sterile Single-Use Devices - Development and Validation
- Submission Requirements for Terminally Sterilized Medical Devices
Related references and norms
- ASTM F543: Standard Specification and Test Methods for Metallic Medical Bone Screws
- ISO 17665: Sterilization of health care products – Moist heat
- ISO 11135: Sterilization of health care products – Ethylene oxide
- ISO 11137-1/2/3/4: Sterilization of health care products - Radiation
- ISO 11607-1/2: Packaging for terminally sterilized medical devices
- ISO 10993-1: Biological evaluation of medical devices
- ASTM F136: Standard Specification for Wrought Titanium-6Aluminum-4Vanadium ELI Alloy
- ASTM F1472: Standard Specification for Wrought Titanium-6Aluminum-4Vanadium Alloy
- ASTM F138: Standard Specification for Wrought 18Chromium-14Nickel-2.5Molybdenum Stainless Steel
Original guidance
This post is licensed under CC BY 4.0 by the author.