Crevice Corrosion Degrades Metaphyseal Sleeves Following Total Knee Arthroplasty: A Retrieval Study

Abstract

Background Surgeons use metaphyseal sleeves in revision total knee arthroplasty (TKA) to compensate for bone loss and improve stability. However, a clinical case series documented corrosion on these devices and associated the subsequent metal release with adverse local tissue reactions. In this study, we investigated corrosion at the mixed-alloy, metaphyseal sleeve–implant interface. We asked the following: (1) How common is corrosion? (2) Does more damage occur at the femoral cobalt chrome alloy (CoCrMo) taper? (3) What damage modes occur? Methods We analyzed 17 femoral and 15 tibial implant-sleeve components following revision surgery. First, corrosion was classified using the Goldberg score and quantified using the axial corrosion (ΔCmax) on CoCrMo implants. Then, moderately and severely corroded devices were imaged using scanning electron microscopy and energy dispersive X-ray spectroscopy. Differences in corrosion on CoCrMo tibial and femoral implants were assessed using nonparametric statistics. Results We observed corrosion on 82% of femoral adapters, 100% of femoral sleeves, 73% of tibial trays, and 86% of tibial sleeves. On CoCrMo femoral adapters, we measured more axial corrosion than on CoCrMo tibial trays ( P = 0.04). The predominant damage modes on femoral adapters included pitting, etching, and oxide debris. On titanium alloy femoral sleeves, we documented a burnishing effect, revealing the underlying microstructure. Conclusions Our findings indicate that mechanically assisted crevice corrosion promotes metaphyseal implant degradation. Should surgeons encounter patients who have metaphyseal sleeves and unexplained pain or suspected metal release, consider measuring metal concentrations after rigorous rule out of competing diagnoses.