Prognostic value of the synovial fluid peroxidation indicators to determine the risk of implant instability in patients with gonarthrosis accompaniedby articular surface defects

Introduction The number of knee arthroplasties continues to increase in the recent years. Poor quality of implants, technical mistakes, excessive load, injury and osteoporosis are among the causes of their instability that have been most cited in the literature. Mechanical causes of instability may be associated with the changes in the peroxydation processes. Purpose To identify peroxidation products and study the activity of catalase, the main antioxidant enzyme, in the synovial fluid of the knee joint harvested prior to arthroplasty and investigate them as possible prognostic criteria of implant instability in primary arthroplasty Materials and methods Samples of the synovial fluid from 270 patients with gonarthrosis accompanied by defects of the articular surface (stage 3) during the operation of primary knee arthroplasty were harvested. Material of this prospective study was synovial fluid components of 70 patients from this cohort assigned progressively to two groups according to similar age, implant used and stability. Group 1 were patients (n = 35, mean age 67.4 ± 3.1 years) with implant instability developed within 3 years postoperatively. Group 2 patients (n = 35, mean age 69.4 ± 2.8 years) had stable implants. Control group 3 (cadaver material) was without any articular pathology that was recorded by an expert (n = 30, age of 68.4 ± 1.92 years). For a predictive value of the research, biochemical tests of the synovial fluid components were studied. Results Changes in the synovial fluid components in groups 1 and 2 that diverged in different directions were in the products of lipid peroxidation (malondialdehyde) and the activity of catalase. In patients of group 1, catalase activity was increased almost 2-fold, and in patients of group 2 it was reduced by 30% relative the control group. The content of malonic dialdehyde was increased only in group 2. Conclusions The parameters of lipid peroxidation products and the activity of the antioxidant enzyme system in the synovial fluid seem to be possible criteria for predicting instability after knee arthroplasty.