Volume 3, Issue 3 (March 2006)
Survey of Orthopedic Implant Cleanliness Test Methods
In the past, orthopedic implant cleanliness assessment has largely relied on visual and microbiological evaluations; this may not be the case in the future. Test methods to quantity and identify manufacturing residues may need to be added to the cleanliness toolbox to verify that contact materials have been removed to acceptable levels. ASTM has begun exploring this new territory with the F04.15.17. Cleanliness Testing Committee. This paper addresses the need for test methods by reporting a few techniques that may be successful in assessing the cleanliness of metallic implants. The survey describes an extraction technique and several methods that quantify categories of typical contact materials, such as machining oils, coolants and detergents. The methods range from simple gravimetric measurements to employing analytical instrumentation, including Total Organic Analyzers, Inductively Coupled Plasma Spectrometers and Fourier Transform Infrared Spectrometers. The approach of classifying residues as particular categories of contact materials facilitates the application of the techniques across many products and manufacturing processes and allows for a greater degree of standardization, as opposed to identifying specific components of an individual material. The methods described may prompt discussions and provide guidance for future ASTM efforts to develop new standards for orthopedic implants.