Multi-component Zr based biocompatible alloys with modulus ≤50 GPa and density ~2.8 gm/cm3 for biomedical application

Abstract

Orthopaedic implants are manufactured to replace damaged bone or joint. These implants are intended to treat the skeletal deformities and restore the normal skeletal function. The demand for orthopaedic implants has been increased tremendously, for the ageing population, with the increasing risk of osteoporosis, osteoarthritis. The Major segments in implant dominants are the knee, spine, hip, dental and trauma incidents. According to Allied market research, a UK based company (https://www.alliedmarketresearch.com/business-and-market-research) had revealed the orthopaedic implants market was around $45,901 million in 2017 and is expected to reach $66,636 million by 2025. In India, Hospaccx Healthcare Business Consultancy is one of the leading Healthcare and Hospital Consultancy (https://hhbc.in/orthopaedic-market-scenario-of-india/ ) has published that Indian Orthopedic market is around USD 450 million in 2018 and the market is growing at over 30% per year which is considered to be the most dynamic sector in India. In recent years the Government of India has implemented several policy measures to address the challenges of medical devices industry. Among them, R&D related important point is ‘Make in India’ initiative for promoting indigenous manufacturing where medical devices are one of the categories. ‘Swastha Bharat’ is for health mission. Similarly, different R&D funding agencies of Government of India like Department of Bio-Technology (DBT) has chosen its thrust area as ‘Biomedical Engineering’, Department of Science and Technology (DST) has introduced Biomedical Device and Technology Development Program (BDTD). CSIR in its R&D activities has marked healthcare research as one of the niche areas. Indian Government has also implemented a plan to reduce the price of surgery and now with the policy standard and widely used implants such as (i) cobalt-chromium (Co-Cr) in knee replacement surgery which is costing Rs 54,720 against the earlier cost of Rs 1,58,324 (ii) The price of special metals like titanium and oxidised zirconium (Oxinum) has been slashed by almost 70%, to Rs 76,600 from Rs 2.49 lakhs. (iii) In this plan it keeps a provision for revised knee replacement, if the primary replacement fails, prices of next implants will be cut by 59%. Here, it can be referred that Co-Cr alloy contains nickel as an alloying element and nickel has a carcinogenic effect. The Co-Cr, Steel 316L, Ti and Ti-alloys which are generally used as common implant materials have very high mechanical properties. The modulus of elasticity lies in the range of (100-260) GPa while in comparison cortical bone is in the range of (10-30) GPa. The dissimilarity in mechanical property between bone and implant creates a stress shielding effect which spoils the bone in and around the periphery of the implant and sometimes further implants replacement is required. Therefore, the proposed project deals with Zr-Ti-Ca-Si-Fe alloy system having a targeted modulus of elasticity near to that of bone and will be made with biocompatible constituent alloying elements to avoid any carcinogenic effect in the human body.