Development of a novel biodegradable porous iron-based implant for bone replacement

Abstract

Bone replacement and osteosynthesis require materials which can at least temporarily bear high mechanical loads. ideally, these materials would eventually degrade and would be replaced by bone deposited from the host organism. to date several metals, notably iron and iron-based alloys have been identified as suitable materials because they combine high strength at medium corrosion rates. However, currently, these materials do not degrade within an appropriate amount of time. therefore, the aim of the present study is the development of an iron-based degradable sponge-like (i.e. cellular) implant for bone replacement with biomechanically tailored properties. We used a metal powder sintering approach to manufacture a cylindrical cellular implant which in addition contains phosphor as an alloying element. No corrosion inhibiting effects of phosphorus have been found, the degradation rate was not altered. implant prototypes were tested in an animal model. Bone reaction was investigated at the bone-implant-interface and inside the cellular spaces of the implant. newly formed bone was growing into the cellular spaces of the implant after 12 months. Signs of implant degradation were detected but after 12 months, no complete degradation could be observed. In conclusion, ironbased open-porous cellular biomaterials seem promising candidates for the development of selfdegrading and high load bearing bone replacement materials.

Local and systemic inflammation after implantation of a novel iron based porous degradable bone replacement material in sheep model

“…In previously published parts of this study, we were able to show that degradation occurs in clinical animal experiments but does not reach the desired level for open porous implants made of iron with 0.6 wt.% of phosphorus 29 . This finding is in accordance with those by Kraus et al who implanted pins made of Fe-10Mn-1Pd and Fe-21Mn-0.7C-1Pd into the femoral mid-diaphyseal region of rats 30 .…”

“…In our own previous work, a degradable metal implant was developed 28 , 29 . The material is an open cell metal foam with a nominal cell size of 45 pores per inch, porosities of 82% and 87% and has been manufactured by means of a powder metallurgical replication method.…”

“…In the last step, slightly conical implants ( Ø bottom = 10 mm, Ø top = 10.2 mm, h = 15 mm) were cut by waterjet cutting. To eliminate oxides caused by the water cutting process the implants were finally reduced in pure hydrogen at 800 °C 29 . The final fabricated implant and its surgical implantation is shown in Fig.…”

Local and Systemic Inflammation After Implantation of a Novel Iron Based Porous Degradable Bone Replacement Material in Sheep Model

“…The wound was closed by stitches. Under pain control with Buprenorphin-HCl 0.324 mg (Temgesic, Essex Pharma, Munich, Germany) the animals started weighting the implantation site at the second day after surgery without limping or other signs of pain [23].…”

Clinical translation and challenges of biodegradable magnesium-based interference screws in ACL reconstruction

“…In addition, great attention should be paid to the Zn toxicity after degradation of Zn-based implants [ 22 ]. The approach of using iron (Fe) or its alloys has been also studied by increasing researchers in orthopaedic field because of their excellent biocompatibility and desirable mechanical properties [ 23 ]. As the magnetic nature of Fe and the production of iron oxide degradation by-products, there are still challenges for the further clinical use of Fe-based orthopaedic implants [ 24 ].…”