ISO 6475:1989 defines mechanical requirements and associated test methods for specific metal bone screws used in surgical implants: screws with an asymmetrical thread and a spherical under-surface.
This standard is typically used to support design verification and QA/QC testing for osteosynthesis bone screws, where controlled mechanical measurements are needed to demonstrate consistent performance. If you need help matching your screw design and the cited edition to an appropriate test setup, you can contact our team.
ISO 6475:1989 — Implants for surgery — Metal bone screws with asymmetrical thread and spherical under-surface — Mechanical requirements and test methods
ISO 6475:1989 focuses on mechanical requirements and laboratory test methods for a defined bone-screw style (asymmetrical thread with spherical under-surface). It is commonly referenced alongside dimensional and material standards used in surgical implant manufacturing and verification.
The standard also includes important limitations: results from bench testing do not necessarily correlate directly to clinical application, so test intent and acceptance criteria should be interpreted in the context of the intended device design and risk management.
Quick Definition
Document type: Mechanical requirements with associated test methods (mixed requirements + test method content).
Applies to: Metal bone screws with asymmetrical thread and spherical under-surface used as surgical implants.
Common purpose: Design verification and routine quality checks using standardized mechanical test conditions.
What This Standard Covers
ISO 6475:1989 addresses mechanical requirements and test methods for the specified screw geometry, and it is built on related implant standards for screw dimensions and stainless-steel material.
Scope boundaries to keep in mind: The standard is not intended to cover all safety considerations for clinical use, and mechanical test results are not a direct predictor of in-body performance.
Why This Standard Matters in Testing
For medical device manufacturers and testing labs, ISO 6475:1989 provides a repeatable mechanical evaluation framework for a defined class of bone screws. Using standardized mechanical checks helps support consistent product release decisions, supplier controls, and design verification documentation.
Because ISO 6475:1989 ties into referenced dimensional and material standards, it is often used as part of a larger verification package rather than as a stand-alone test activity.
Common Materials, Product Types, or Applications Covered
Common product types: Orthopedic/trauma bone screws within the geometry described by the standard (asymmetrical thread; spherical under-surface).
Common materials: Stainless-steel bone screws are explicitly addressed through referenced stainless-steel implant material standards and the standard’s annex content.
Common application area: Internal fixation/osteosynthesis devices where bone screws are used with plates and corresponding surgical tools.
Common Test or Verification Workflow
Workflows using ISO 6475:1989 typically follow a controlled verification sequence that starts with confirming the screw type and dimensions covered, then selecting fixtures and measurement ranges aligned with the required mechanical checks.
Common workflow elements: Specimen identification and dimensional confirmation, mechanical testing using appropriate fixtures and load/torque measurement, and test reporting suitable for design verification files and/or routine QC release.
Equipment Commonly Used for This Standard
ISO 6475:1989 points to mechanical testing of relatively small implant components, so equipment selection is typically driven by measurement sensitivity, alignment control, and the ability to run repeatable screw-specific fixturing.
Common equipment: Electromechanical universal testing machines (for controlled loading with custom fixtures), torque/torque-angle test systems or torque transducers (for rotational mechanical checks), dedicated screw-holding fixtures, and calibrated measurement instrumentation for force, torque, and displacement/angle.
Because screw geometry and drive interface details influence fixturing, the practical requirement is often a custom fixture set matched to the specific screw family and the exact test defined in the cited edition. If you are selecting a frame, torque sensor capacity, or fixture concept, you can request a detailed quote for an equipment package aligned to your screw size range and test throughput.
How to Read This Designation or Revision
Designation format: ISO 6475:1989.
What the year means: The year identifies the published edition being cited. For regulated or customer-controlled verification, the specific dated edition can matter for acceptance criteria, fixture details, and reporting expectations.
Revision sensitivity: If a customer specification or submission file cites ISO 6475:1989, keep the test plan aligned to that exact edition unless the requirement owner explicitly approves an update.
Related Standards, Methods, or Frameworks
ISO 6475:1989 is commonly used with companion implant standards that define the dimensional baseline and the metallic material expectations for stainless-steel surgical implants.
Frequently paired references: ISO 5835 (metal bone screw dimensions) and ISO 5832-1 (wrought stainless steel for surgical implants). ISO’s catalog history also shows earlier part standards (ISO 6475-1 and ISO 6475-2) that were withdrawn when ISO 6475:1989 consolidated this topic.
Talk With Us About ISO 6475 Testing Setup
If you are building a verification or QC workflow around ISO 6475:1989 and need help aligning fixtures, torque/force measurement ranges, and calibration practices to your screw sizes, talk with our team about your application.