ARTHROPLASTY
Elevation of circulating HLA DR(+) CD8(+) T-cells and correlation with chromium and cobalt concentrations 6 years after metal-on-metal hip arthroplasty
OrthoEvidence Journal (OE Journal) - ACE Report
OE Journal. 2025;13(20):1 Acta Orthop. 2011 Feb;82(1):6-12. Epub 2010 Dec 2985 patients undergoing total hip arthroplasty (THA) were randomized to receive either a metal-on-metal bearing or a metal-on-polyethylene bearing. The primary outcome was elevation of circulating HLA DR+ CD8+ T-cells and correlation with chromium and cobalt concentrations. Results indicated that metal-on-metal THA increased chromium and cobalt concentrations which resulted in a correlation with immunological reactions. This was associated with the increase in HLA DR+CD8+ T-cells and a decrease in B-cells.
Was the allocation sequence adequately generated?
Was allocation adequately concealed?
Blinding Treatment Providers: Was knowledge of the allocated interventions adequately prevented?
Blinding Outcome Assessors: Was knowledge of the allocated interventions adequately prevented?
Blinding Patients: Was knowledge of the allocated interventions adequately prevented?
Was loss to follow-up (missing outcome data) infrequent?
Are reports of the study free of suggestion of selective outcome reporting?
Were outcomes objective, patient-important and assessed in a manner to limit bias (ie. duplicate assessors, Independent assessors)?
Was the sample size sufficiently large to assure a balance of prognosis and sufficiently large number of outcome events?
Was investigator expertise/experience with both treatment and control techniques likely the same (ie.were criteria for surgeon participation/expertise provided)?
Sì = 1
Incerto = 0,5
Non rilevante = 0
No = 0
La valutazione dei criteri di segnalazione valuta la trasparenza con cui gli autori riportano le caratteristiche metodologiche e sperimentali dello studio all'interno della pubblicazione. La valutazione è suddivisa in cinque categorie che vengono presentate di seguito.
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Randomization
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Outcome Measurements
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Inclusion / Exclusion
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Therapy Description
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Statistics
Detsky AS, Naylor CD, O'Rourke K, McGeer AJ, L'Abbé KA. J Clin Epidemiol. 1992;45:255-65
L'Indice di Fragilità è uno strumento che aiuta l'interpretazione dei risultati significativi, fornendo una misura della forza di un risultato. L'Indice di Fragilità rappresenta il numero di eventi consecutivi che devono essere aggiunti a un risultato dicotomico per rendere il risultato non più significativo. Un numero piccolo rappresenta un risultato più debole, mentre un numero grande rappresenta un risultato più forte.
Perché questo studio era necessario ora?
Elevated metal ion concentrations from metal-on-metal arthroplasties have been associated with immunological reactions. It is hypothesized that an increased concentration of metal ions causes changes in the lymphocyte sub-populations. This study examines the change in concentration of HLA DR+ CD8+ T-cells and the correlation with chromium and cobalt concentrations in patients undergoing metal-on-metal or metal-on-polyethylene total hip arthroplasty (THA).
Qual era la domanda di ricerca principale?
What are the outcomes in HLA DR+ CD8+ T-cell elevation and its correlation with chromium and cobalt concentrations in patients, 6 years after undergoing metal-on-metal total hip arthroplasty (THA) compared to metal-on-polyethylene THA?
Quali erano i risultati importanti?
- Serum concentrations of chromium and cobalt were higher in patients who received the metal-on-metal total hip arthroplasty (THA) compared to patients who underwent metal-on-polyethylene THA when examined at follow-up. (Chromium: 1.05 vs. 0.36 ug/L; p<0.001; Cobalt: 0.86 vs. 0.24 ug/L; p<0.001)
- The metal-on-metal group had a higher percentage of HLA DR+ CD8+ T-cells. (10.6 vs. 6.7%; p=0.03) This had a positive correlation with cobalt and chromium concentrations in patient blood (Pearson's correlation coefficient for cobalt: 0.36, p=0.03; Chromium: 0.39, p=0.02).
- The metal-on-metal group had a lower percentage of B-cells.(9.3% compared to 12.9% in the metal-on-polyethylene group) (p=0.01)
- Comparable immunoglobulin concentrations and Harris hip scores were seen between the two groups. No radiographic signs of loosening, wear or periprosthetic osteolysis were seen with either group at follow-up.
- Both groups of patients had similar concentrations of immunoglobulins IgG (and subgroups 1-4), IgM, and IgA.
Che cosa devo ricordare di più?
Metal-on-metal THA increases cobalt and chromium concentrations at 6-years and produces immunological alterations. There is also a positive correlation with HLA DR+ CD8+ T-cells and chromium and cobalt concentrations. Finally, the metal-on-metal group had a reduction in the percentage of B-cells.
Come influenzerà l'assistenza ai miei pazienti?
There is still a lack of evidence that the increase in HLA DR+ CD8+ T-cells, associated with metal-on-metal THA, causes allergic reactions, aseptic loosening, or periprosthetic pseudotumors. Further studies with a larger population are required to examine these potential associations.
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