The purpose of this study was to evaluate whether the serum level of interleukin 6 (IL-6) could be used to identify the persistence of infection after the first stage of a two-stage revision for periprosthetic joint infection.

Between 2010 and 2011, we prospectively studied 55 patients (23 men, 32 women; mean age 69.5 years; 36 to 86) with a periprosthetic joint infection. Bacteria were identified in two intra-operative tissue samples during re-implantation in 16 patients. These cases were classified as representing persistent infection.

To calculate a precise cut-off value which could be used in everyday clinical practice, a 3 x 2 contingency table was constructed and manually defined.

We found that a serum IL-6 ≥ 13 pg/mL can be regarded as indicating infection: its positive-predictive value is 90.9%. A serum IL-6 ≤ 8 pg/mL can be regarded as indicating an absence of infection: its negative predictive value is 92.1%.

The serum IL-6 level seems to be a reasonable marker for identifying persistent infection after the first stage of a revision joint arthroplasty and before attempting re-implantation.

Cite this article: Bone Joint J 2015;97-B:71–5.

Objective

Mortality rates reported by the National Joint Registry for England and Wales (NJR) were higher following cemented total knee replacement (TKR) compared with uncemented procedures. The aim of this study is to examine and compare the effects of cemented and uncemented TKR on the activation of selected markers of inflammation, endothelium, and coagulation, and on the activation of selected cytokines involved in the various aspects of the systemic response following surgery.

We examined the usefulness of neutrophil CD64 expression in detecting local musculoskeletal infection and the impact of antibiotics on its expression. Of 141 patients suspected of musculoskeletal infection, 46 were confirmed by microbiological culture to be infected and 95 had infection excluded. The median CD64 count of patients with localised infection was 2230 molecules per cell (interquartile range (IQR) 918 to 4592) and that of the patients without infection was 937 molecules per cell (IQR 648 to 1309) (p < 0.001). The level of CD64 correlated with the CRP level in patients with infection, but not in those without infection (r = 0.59, p < 0.01). Receiver operator characteristic curve analysis revealed that CD64 was a good predictor of local infection. When the patients were subdivided into two groups based on the administration of antibiotics at the time of CD64 sampling, the sensitivity for detecting infection was better in those who had not received antibiotics.

These results suggest that measurement of CD64 expression is a useful marker for local musculoskeletal infection.

It is known that wide variability exists among patients in the susceptibility to and outcome from infection. Polymorphisms in genes coding for proteins involved in the response to bacterial pathogens as tumor necrosis factor-alpha(TNF-a), interleukin (IL)-1alpha, IL-1beta, IL-1 receptor agonist, IL-6, IL-10 can influence the amount or function of the protein produced in response to bacterial stimuli. These genetic polymorphisms may influence the susceptibility to and outcome from infection. The aim of the study was to investigate whether genetic variation in genes coding for components of the innate immune response might be a critical determinant of the inflammatory response and the risk for and outcome from severe bacterial infection in individuals with musculoskeletal infections. The relationship between single nucleotide polymorphisms (SNPs) in the above mentioned genes and susceptibility to infection was evaluated. Forty patients with musculoskeletal infections hospitalised at the Orthopaedic Clinic of University Hospital of Larissa, as well as 80 healthy controls were included in the study. Genomic DNA was isolated from peripheral blood from all cases and controls and was extracted according to standard procedures. The following genes with their polymorphic positions were studied: IL 1α (IL 1α promoter −889), IL 1β (IL 1β promoter −511, pos. +3962), IL 1R (IL 1R pos. pst1 1970), IL 1RA (IL 1RA pos. mspa1 11100), IL 4Rα (IL 4Rα pos. +1902), IL 12 (IL 12 promoter −1188), TGF-β (TGF-β exon 1 codon 10, codon 25), TNF-α (TNF-α promoter −308, −238), IL 2 (IL 2 promoter −330, pos. +166), IL 4 (IL 4 promoter −1098, −590, −33), IL 6 (IL 6 promoter −174, pos. +nt 565) and IL 10 (IL 10 promoter −1082, −819, −592). Genotype distribution and allele frequencies in patients and controls were evaluated. There was a significant difference in genotype and allele frequency of IL-1a (T/C −889) p=0.000 (CC, TC) between patients and the control group. Moreover, 2 SNPs of interleukin 4 [IL-4 (T/G −1098) p=0.000 (GG, GT) p=0.009 (TT) and IL-4 (T/C-590) p=0.000 (CC, CT) p=0.006 (TT)] showed significant genotypic and allelic differences between the two groups. Finally, 2 SNPs of interleukin 6 [IL-6 (G/C-174) p=0.000 (CC) p=0.014 (GG), IL-6 G/A nt565) p=0.000 (AA,GA,GG)] and TNF-a [(G/A-308) p=0.034 (AG)] showed significant differences in genotype and allele frequencies between patients and the control group. We observed, for the first time, significant differences in genotype and allele frequencies of TNF-a (G/A-308), IL-1a (T/C -889), IL-4 (T/G -1098), IL-4 (T/C-590), IL-6 (G/C-174) and IL-6 G/A (nt565) in patients with musculoskeletal infections, a fact which points towards the involvement of cytokine gene polymorphisms in the pathogenesis of infection