Gelsolin (GSN) is a protein whose function in the cytoplasm is to regulate intracellular actin assembly, while circulating plasma GSN has been implicated in the clearance of cellular byproducts via the body's scavenger system. In knee synovial fluid, GSN appears to be protective of inflammation as lower levels have been found in patients with rheumatoid arthritis while higher levels have been demonstrated in hypersensitivity reactions to metallic implants. The purpose of this study is to define the role of GSN in painful total knee arthroplasty (TKA) patients as a biomarker to distinguish septic from aseptic diagnoses. After Institutional Review Board (IRB) approval, 50 patients were enrolled in the study into two cohorts. 25 patients presented with a painful TKA and 25 patients had a painful native knee with primary osteoarthritis (OA). Synovial fluid was obtained from each patient's affected knee. Appropriate lab and culture data was also obtained from the painful TKA group. An ELISA was used to determine GSN levels and the groups were compared. Two tailed Student's t tests were used to compare means while Pearson's Correlation Coefficient and linear regression analyses were used to determine association between laboratory findings and GSN levels.Introduction
Methods
Since the recall of some metal on metal (MoM) THR bearings, surgeons have seen patients with pain, elevated Co and Cr levels and adverse local tissue reactions (ALTR). While many variables may contribute to THR MoM failures, many times these variables are not present in patients who present with symptoms. We investigate the possible genetic predilection of a group of patients who were revised after MoM THR surgery for pain, high Co/Cr levels and ALTR. IRB approval was obtained prior to our study. We have analyzed 19 control (asymptomatic MoM THR patients > 6 years after surgery) and 19 disease (revised MoM THR for high metal ions and ALTR). The 38 sample intensity files were subject to sample Quality Control (QC) using Contrast QC (< 0.4) with an Affymetrix Genotyping Console. The resulting 38 sample files with genotype calls were loaded and further analyzed using the Association Workflow in Partek Genomics Suite 6.6 (Partek, Missouri). Hardy-Weinberg equilibrium test was performed on the single nucleotide polymorphism (SNP) level. The difference between the observed and expected frequencies of each allele at each locus were tested by Fisher's exact test and χ2 test. To get the working SNP list, two filters were used: (1) a SNP no-call rate should be less than 5%, and (2) minor allele frequency of a SNP should be greater than 5%. After filtering, association analysis of the SNPS with disease was done using Chi2 Test. In this study, χ2 statistic was used to assess the difference in allele frequencies between the control and disease samples. The value of χ2 statistic, degrees of freedom, and the associated p-value for each SNP were calculated. Dot Plot was used to visualize the genotypes of all samples. To measure the non-random association of alleles at different loci, Linkage Disequilibrium analysis was performed using the neighborhood size of 20 and statistic r2. The resulting correlations show the value of r2 for SNPs. The r2 = 1 means that two SNPs are tightly associated.INTRODUCTION
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