Analysis of Corrosion Deposit on Hip Explant

A concerned customer sent us a hip implant displaying visible signs of corrosion. To investigate the issue, we utilized XPS (X-ray Photoelectron Spectroscopy) to analyze the light green and off-white corrosion deposit on the CoCrMo alloy hip implant, located precisely on the femoral stem just below the taper fitted to the head. The results of our analysis unveiled a complex chemical composition. The deposit was predominantly a combination of chromium phosphate and chromium oxide, interspersed with bone minerals and polypeptides. Additionally, various other compounds involving chromium, molybdenum, and cobalt were also identified within the deposit.

Chromium oxide concentrations typically provide robust corrosion resistance in most environments; however, chromium proves to be less resistant to phosphate attacks. Intriguingly, both cobalt and molybdenum, components of the CoCrMo alloy, are prone to forming phosphates as well. Notably, the phosphates of cobalt and molybdenum exhibit lower solubility compared to those of chromium. Consequently, the corrosion deposit accumulating around the hip implant tends to be richer in chromium content than cobalt or molybdenum. This nuanced understanding underscores the intricate chemical reactions transpiring on the implant’s surface, emphasizing the critical need to comprehend these corrosion mechanisms thoroughly. Such understanding is pivotal for enhancing the longevity and performance of CoCrMo alloy implants.

At our facility, we specialize in addressing material-related issues like the corrosion deposit problem described. Customers frequently approach us for troubleshooting and comprehensive analysis tailored to their specific situations. We offer personalized suggestions to tackle these challenges effectively. If you’re facing corrosion-related concerns, please don’t hesitate to contact us. We are here to discuss and address your corrosion materials analysis needs comprehensively.