In situ degradation of metal-alloy implants is undesirable for two reasons: the degradation process may decrease the structural integrity of the implant, and the release of degradation products may elicit an adverse biological reaction in the host Degradation may result from electrochemical dissolution phenomena, wear, or a synergistic combination of the two Electrochemical processes may include generalized corrosion, uniformly affecting the entire surface of the implant, and localized corrosion, affecting either regions of the device that are shielded from the tissue fluids (crevice corrosion) or seemingly random sites on the surface (pitting corrosion) Electrochemical and mechanical processes (for example, stress corrosion cracking, corrosion fatigue, and fretting corrosion) may interact, causing premature structural failure and accelerated release of metal particles and ions

The clinical importance of degradation of metal implants is evidenced by particulate corrosion and wear products in tissue surrounding the implant, which may ultimately result in a cascade of events leading to periprosthetic bone loss Furthermore, many authors have reported increased concentrations of local and systemic trace metal in association with metal implants1,4,5,9-11,14,18,25,26,28,29,47,49-55,58,71,72,75-77,87,90,108-110 There also is a low but finite prevalence of corrosion-related fracture of the implant

This review focuses on electrochemical corrosion phenomena in alloys used for orthopaedic implants A summary of basic electrochemistry is followed by a discussion of retrieval studies of the response of the implant to the host environment and the response of local tissue to implant corrosion products The systemic implications of the release of metal particles also are presented Finally, future directions in biomaterials research and development …

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Corrosion of metal orthopaedic implants.

The present invention relates generally to systems and methods for measuring an analyte in a host. More particularly, the present invention relates to systems and methods for transcutaneous measurement of glucose in a host.

Transcutaneous analyte sensor

Validation of corrosion rates measured by the Tafel extrapolation method

Systems and methods for applying time-dependent algorithmic compensation functions to data output from a continuous analyte sensor. Some embodiments determine a time since sensor implantation and/or whether a newly initialized sensor has been used previously.

Systems and methods for processing analyte sensor data

Application of porous ceramics for the attachment of load bearing internal orthopedic applications

Orthopedic appliances of type 316 (SMO) stainless steel were examined in detail after being removed from human subjects. Techniques included conventional microscopy with various lighting methods, together with electron microscope fractography. Corrosion, fatigue failure, and manufacturing defects were identified and statistically tabulated. Corrosion damage occurred on 91% of all multicomponent devices and the overall incidence of fracture failure was 9%. These results indicate an urgent ueed for stronger, more corrosion-resistant implant alloys.

Corrosion and fracture of type 316 SMO orthopedic implants.

Corrosion properties of iron and steel

Corrosion resistance is particularly important in medical treatments requiring implantation of metallic objects in the human body. Unfortunately, weight loss measurements and other conventional corrosion testing techniques are insufficiently sensitive and difficult to adapt to in vivo environments. The linear polarization technique can be used to remotely meaure the corrosion rates of metals implanted in tissue using needle probes. The principles of this technique are reviewed and the results of tests performed on steel, cobalt, and molybdenum implanted in experimental animals are discussed.

N.D. Greene

Papers

Corrosion and fracture of type 316 SMO orthopedic implants.

Corrosion properties of iron and steel

Corrosion rate measurements in vivo.

Electrochemical properties of Fe and steel.

Comparison of the in vivo and in vitro corrosion of 18-8 stainless steel and titanium.