Backgrounds: The purpose of this study was to investigate clinical relevance of preoperative screening for metal sensitivity (MS), and to assess whether there is any difference in the MS after total knee arthroplasty (TKA) between oxidized zirconium (OxZr) and cobalt-chrome (Co-Cr) implants.
Methods: A total of 48 subjects referred for TKA were enrolled the study with no history of metal allergy. After preoperative screening, we prospectively evaluated subjects, who were received either of 2 components, by comparing values of skin patch test, lymphocyte stimulation test (LST), and serum ion sampling.
Results: Preoperatively, positive rates to Co, Ni, Cr were 2.1, 6.3, 0 (%, patch test), and were 6.3, 29.2, 16.7 (%, lymphocyte stimulation test (LST)), respectively. Postoperatively, 1 subject (4%) newly tested positive to Va in the Co-Cr group, and positive rates of LST to Co, Ni, and Cr were higher in the Co-Cr group. As the result of serum ion sampling, there was a slight increase of Co and Ni levels in the Co-Cr group. However, none of the subjects has developed cutaneous signs attributable to metal sensitization, and no evidence of the implant loosening was confirmed at the latest examination.
Conclusions: The finding of our study suggested that the past history alone was insufficient for identifying subjects with MS, and preoperative screening might be useful for subjects with no history of allergy. However, we could not conclude the benefit of the OxZr implant during short post-operative period.
Keywords: Metal sensitivity, total knee arthroplasty, oxidized zirconium, allergy