Alloys for Orthopaedic Implant Use

Abstract

The paper compares four alloys in orthopaedic implant use on the basis of their performance in laboratory tests. The alloys compared were cast Co–Cr–Mo, powder metallurgy (PM) Co–Cr–Mo, Ti 318 and Ti 550. Tensile, corrosion fatigue, and corrosion tests were carried out and the effect of heat treatment and of surface treatment was investigated. The corrosion fatigue tests ranked the alloys in the following order of merit (1) Co–Cr–Mo (PM), (2) Ti 550, (3) Ti 318, and (4) cast Co–Cr–Mo. The corrosion tests demonstrated for cast Co–Cr–Mo the effect of passivation, steam sterilization, and texturing, and for Ti 318 the effect of oxidizing, anodizing, and acid etch/shot peening. It was concluded that for joint replacement applications requiring the highest corrosion fatigue strength regardless of cost and neglecting the possible importance of elastic modulus, Co–Cr–Mo (PM) was best. For applications requiring ease of manufacture and allowing a lower corrosion fatigue strength, cast Co–Cr–Mo was the material of choice. For most other applications and in particular where high corrosion fatigue strength at a reasonable cost was required, the Ti alloys offered worthwhile advantages.

Temperature effects on the lattice constants and crystal structure of a Co-27Cr-5Mo low-carbon alloy

“…At each temperature considered, there are different V uc values as the calculated lattice parameters change with temperature (Eqs. [2] through [5]). …”

“…[1,2,3] In addition, the alloy properties can be further improved through proper heat treatments aimed at controlling the volume fraction of microstructural components, as well as grain size. [4] In Co-Cr-Mo-C alloys, two crystal structures can be developed, hexagonal-close-packed (hcp) and face-centered-cubic (fcc), with hcp being the thermodynamically stable phase at room temperature.…”

The effects of implant composition on extensor tenosynovitis in a canine distal radius fracture model

“…11,[13][14][15][16][17]19,22,24 This black peri-implant staining was thought to be benign. 30 Early studies of soft tissue supported the notion of minimal adverse response in blackened tissue areas, 17,26,31,32 but numerous reports found a marked tissue reaction in peri-implant tissue. [21][22][23][24][25]33 Locally irritating metallic debris results in abundance of histiocytes and giant cells in peri-implant softtissue specimens.…”