Abstract
(1) Background: The objective of the present study was to review the clinical and radiological results of a small-head, MoM bearing in primary THA and to determine blood metal ion levels at long-term follow-up. (2) Methods: We retrospectively evaluated the clinical and radiological results of 284 small-diameter, MoM 28-mm Metasul THA at a mean follow-up of 14.5 years, and measured blood metal ion concentrations in 174 of these patients. (3) Results: After 14 years, survival free for revision due to any reason was 94%. Proximal femoral osteolysis was seen in 23% of hips, and MRI demonstrated ARMD in 27 of the 66 investigated hips (41%). Mean cobalt, chromium, and titanium ion concentrations were 0.82 µg/L (range 0.22–4.45), 1.51 µg/L (0.04–22.69), and 2.68 µg/L (0.26–19.56) in patients with unilateral THA, and 2.59 µg/L (0.43–24.75), 2.50 µg/L (0.26–16.75), and 3.76 µg/L (0.67–19.77), respectively in patients with bilateral THA. Twenty-nine percent of patients showed cobalt or chromium ion levels > 2 µg/L. (4) Conclusions: Despite good clinical long-term results, increased blood metal ion levels (cobalt or chromium > 2 µg/L) were found in approximately one-third of asymptomatic patients, and proximal femoral osteolysis and ARMD were frequently seen in this cohort. Blood metal ion analysis appears helpful in the long-term follow-up of these patients in order to identify individuals at risk. In accordance with contemporary consensus statements, symptomatic patients with elevated metal ion levels and/or progressive osteolysis should be considered for additional CT or MARS MRI to determine the extent of soft tissue affection prior to revision surgery. Further studies are necessary to investigate the clinical relevance of ARMD in asymptomatic patients with small-head, MoM THA.
Highlights
Second-generation, small-head, metal-on-metal (MoM) total hip replacements were reintroduced in 1988 by Weber [1], and initiated the rise of metal-on-metal hip arthroplasties at the beginning of thisMaterials 2020, 13, 557; doi:10.3390/ma13030557 www.mdpi.com/journal/materialsMaterials 2020, 13, 557 century
Logistic regression analysis showed no association between the presence of periprosthetic osteolysis and blood metal ion levels of cobalt, chromium (OR, 1.01; 95% confidence interval (CI), 0.85–1.21; p = 0.905), or titanium (OR, 0.88; 95% CI, 0.66–1.16; p = 0.362)
The results of this study show that despite good clinical results, radiological findings of femoral osteolysis and adverse reaction to metal debris (ARMD) were frequently seen in this cohort of patients with well-functioning small-head, metal-on-metal total hip arthroplasties (THA), and 29% of patients demonstrated elevated cobalt or chromium ion levels, i.e., > 2 μg/L, at long term follow-up
Summary
Second-generation, small-head, metal-on-metal (MoM) total hip replacements were reintroduced in 1988 by Weber [1], and initiated the rise of metal-on-metal hip arthroplasties at the beginning of thisMaterials 2020, 13, 557; doi:10.3390/ma13030557 www.mdpi.com/journal/materialsMaterials 2020, 13, 557 century. Especially in large-diameter, metal-on-metal total hip arthroplasties (THA), and the growing incidence of adverse local tissue reactions related to metal wear, led to a swift decrease in the use of those implants in the subsequent years [3,4,5,6]. MoM bearings are rarely used nowadays, the systematic follow-up of these patients will continue to be of clinical importance due to the large number of metal-on-metal articulations that were implanted in past decades, especially in younger patients [7]. Some authors have recently raised concerns about the late onset of ARMD associated with increased metal wear of small-diameter, MoM implants [11,12,13], the results of metal ion analyses in the long-term follow-up of these patients are not clear
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
