When this test applies
Required for devices that contact or are anchored in bone, under ISO 10993-1:2025. The bone route exists because the osseous response is a different biology from soft tissue: what matters is new bone formation against the implant, resorption at the interface, and whether a fibrous membrane forms between the two. A soft-tissue implantation result does not predict any of that. At two weeks the bone site is still in the reactive phase — surgical trauma is resolving, woven bone is forming and the interface has not organised. This timepoint characterises the acute osseous response, and it is where a frankly cytotoxic or particulate-shedding material declares itself.
When to run it
Late, and only once the material, the surface finish and the manufacturing process are locked — surface topography drives the osseous response as much as chemistry does, so a finishing change after the implants go in means starting over. Your biological evaluation plan should settle which timepoints the device category requires before any of them are commissioned.
What a pass tells you
That the histological response at the test sites, scored against the control sites per ISO 10993-6 Annex E, produced an irritation ranking of 2.9 or less — classed as a non-irritant in bone over a 2 weeks implantation period.
What it does not tell you
A clean two-week bone result says nothing about whether the interface goes on to remodel into organised lamellar bone or into a fibrous membrane — that divergence appears at thirteen weeks and later, which is why the longer bone studies exist. It also says nothing about systemic effects, genotoxicity or sensitization, each of which is a separate endpoint.
Method
Testing per ISO 10993-6:2016 in the rabbit. Solid samples are implanted directly — there is no extraction step — with sample geometry prepared to the dimensions ISO 10993-6 specifies for the bone route, and placed in prepared cortical sites alongside control implants in the contralateral position. After 2 weeks the sites are explanted and processed for bone histology, then reviewed by a pathologist and scored to derive an irritation ranking per Annex E.
Where it runs
This method is internationally sourced. The laboratory is ISO/IEC 17025 accredited and GLP certified, and the report is issued under Groenakker cover, in Groenakker’s report template or in your document template on request at no extra cost.
Usually ordered alongside
The thirteen- and twenty-six-week bone timepoints, which answer the remodelling question this one cannot. Cytotoxicity, sensitization and irritation as the baseline battery, and the intramuscular or subcutaneous studies where the device also contacts soft tissue.
