Abstract
Objectives This study aims to evaluate the biodegradability and biocompatibility of an alloy
of iron and manganese (Fe30Mn) in a bone model in vivo.
Methods Resorption of a Fe30Mn wire was compared with traditional permanent 316L stainless
steel (SS) wire after bilateral transcondylar femoral implantation in 12 rats. Evaluation
of biodegradation over 6 months was performed using radiography, post-mortem histology
and microscopic implant surface analysis.
Results Corrosion and resorption of the novel iron-manganese implant with formation of an
iron oxide corrosion layer was noted on all post-mortem histological sections and
macroscopic specimens (corrosion fraction of 0.84 and 0 for Fe30Mn and 316L SS, respectively).
Increased bone ongrowth was observed at the wire-bone interface (bone ongrowth fraction
of 0.61 and 0.34 for Fe30Mn and 316L SS, respectively). Occasionally, poorly stained
newly formed bone and necrotic bone in contact with corrosion was seen. In bone marrow,
Fe30Mn alloy was scored as a mild local irritant compared with 316L SS (biocompatibility
score of 8.8 and 5.3, respectively). There was no evidence of systemic adverse reaction.
Clinical Significance Resorbable iron-manganese alloys may offer a promising alternative to permanent metallic
implants. Further in vivo studies to control implant resorption at a rate suitable
for fracture healing and to confirm the biocompatibility and biosafety of the resorbable
Fe30Mn metallic implant are necessary prior to use in clinical settings.
Keywords
bioabsorbable metals - iron-manganese alloys - corrosion - biocompatibility
