Testing and Characterization of Ultra-High Molecular Weight Polyethylene (UHMWPE) Used in Orthopedic Devices
This guidance applies to class II and class III orthopedic devices, including spinal devices, that contain UHMWPE (Ultra-High Molecular Weight Polyethylene). It provides recommendations for characterization and testing of different types of UHMWPE materials: conventional UHMWPE, highly crosslinked UHMWPE (HXLPE), antioxidant highly crosslinked UHMWPE (AO-HXLPE), and non-conventional UHMWPE.
What You Need to Know? 👇
What are the main types of UHMWPE materials used in orthopedic devices?
There are four main categories: conventional UHMWPE, highly crosslinked UHMWPE (HXLPE), antioxidant highly crosslinked UHMWPE (AO-HXLPE), and non-conventional UHMWPE. Each type has different processing methods and material properties that affect characterization requirements.
What key information must be provided for UHMWPE material characterization in FDA submissions?
You must provide starting resin type, resin consolidation method, terminal sterilization method, and specific material properties. For radiation sterilization, include radiation type, delivered dose, packaging details, and environment conditions during packaging.
How does highly crosslinked UHMWPE differ from conventional UHMWPE in testing requirements?
HXLPE requires additional characterization including radiation dose, crystallinity, melting temperature, trans-vinylene index, post-accelerated aging testing, crosslink density, fatigue resistance testing, free radical concentration, and thermal processing details beyond conventional UHMWPE requirements.
What special considerations apply to antioxidant-containing UHMWPE materials?
AO-HXLPE requires assessment of antioxidant concentration, stability, effect on wear mechanism, impact on material consolidation, and comprehensive biocompatibility evaluation. Wear testing under normal and abrasive conditions is particularly important for these materials.
What biocompatibility endpoints must be addressed for permanently implanted UHMWPE devices?
Ten endpoints must be addressed: cytotoxicity, sensitization, irritation/intracutaneous reactivity, acute systemic toxicity, material-mediated pyrogenicity, subchronic toxicity, genotoxicity (mutagenicity and clastogenicity), implantation, chronic toxicity, and carcinogenicity per ISO 10993-1.
What shelf life considerations are critical for UHMWPE-containing orthopedic devices?
Package integrity testing must validate sterility maintenance and shelf life claims. UHMWPE materials with unstable free radicals may degrade during storage, requiring stability assessment for the entire proposed shelf life using real-time or properly validated accelerated aging methods.
What You Need to Do 👇
Recommended Actions
- Determine the type of UHMWPE material being used (conventional, HXLPE, AO-HXLPE, or non-conventional)
- Perform material characterization testing based on UHMWPE type
- Conduct biocompatibility evaluation according to ISO 10993-1
- Validate package integrity and shelf life
- Submit Pre-Submission for non-conventional UHMWPE or when planning animal studies
- Prepare complete test reports following FDA’s recommended format
- Consider submitting a Pre-Submission to determine testing requirements for investigational devices
- Document all material processing steps and controls
- Validate sterilization process and package integrity
- Develop a comprehensive shelf-life testing program including both accelerated and real-time aging studies
Key Considerations
Non-clinical testing
- Material characterization testing based on UHMWPE type
- Mechanical properties testing (tensile, impact resistance, density)
- Chemical properties testing (crystallinity, melting temperature, oxidation index)
- Fatigue resistance testing
- Wear testing for articulating components
- Shelf-life testing
Labelling
- Shelf life and expiration date
- Sterilization method
- Storage conditions
Biocompatibility
- Cytotoxicity
- Sensitization
- Irritation
- Acute systemic toxicity
- Material-mediated pyrogenicity
- Subchronic toxicity
- Genotoxicity
- Implantation
- Chronic toxicity
- Carcinogenicity
Safety
- Package integrity testing
- Sterilization validation
- Stability testing during shelf life
Other considerations
- Starting resin identification
- Resin consolidation method
- Terminal sterilization method
- For AO-HXLPE: antioxidant concentration and stability
- For non-conventional UHMWPE: additional specific testing based on material properties
Relevant Guidances 🔗
- Use of ISO 10993-1 for Biological Evaluation and Testing of Medical Devices
- Recommended Format and Content for Non-Clinical Bench Performance Testing in Medical Device Premarket Submissions
- Shelf Life and Stability Testing for Medical Devices
- Q-Submission Program: Strategic Framework for FDA Interactions in Medical Device Development
Related references and norms 📂
- ASTM F648: Standard Specification for Ultra-High-Molecular-Weight Polyethylene Powder and Fabricated Form for Surgical Implants
- ASTM F2759: Standard Guide for Assessment of the Ultra High Molecular Weight Polyethylene Used in Orthopedic and Spinal Devices
- ASTM F2565: Standard Guide for Extensively Irradiation-Crosslinked Ultra-High Molecular Weight Polyethylene Fabricated Forms for Surgical Implant Applications
- ISO 11607-1: Packaging for terminally sterilized medical devices – Part 1: Requirements for materials, sterile barrier systems and packaging systems
- ISO 11607-2: Packaging for terminally sterilized medical devices – Part 2: Validation requirements for forming, sealing and assembly processes
- ASTM F1980: Standard Guide for Accelerated Aging of Sterile Barrier Systems for Medical Devices
Original guidance
- Testing and Characterization of Ultra-High Molecular Weight Polyethylene (UHMWPE) Used in Orthopedic Devices
- HTML / PDF
- Issue date: 2019-04-26
- Last changed date: 2019-04-24
- Status: FINAL
- Official FDA topics: Medical Devices, Investigational Device Exemption (IDE), Premarket Approval (PMA), 510(k), Orthopedic
- ReguVirta ID: eeb480b7d0328f4205af0ec82b115e5c