Pain perception in knees with circumscribed cartilage lesions is associated with intra-articular IGF-1 expression

Abstract

Background: Circumscribed cartilage defects are considered as prearthritic lesions and lead to differential intra-articular cytokine expression. Mechanisms of associated pain development and influence of smoking behavior are not yet fully understood in humans.Purpose: This study aimed to reveal relations between synovial cytokine levels in knees with circumscribed cartilage defects and pain sensation.Study Design: Descriptive laboratory study.Methods: In a clinical trial, knee lavage fluids of 42 patients with circumscribed cartilage lesions treated by either microfracturing (n = 19) or by autologous chondrocyte implantation (n = 23) and fluids of 5 healthy control individuals were prospectively collected. Preoperative knee pain was evaluated according to frequency and strength; subjective knee function was assessed using a visual analog scale and the International Knee Documentation Committee (IKDC) score. Synovial concentrations of aggrecan, insulin-like growth factor (IGF)-I, basic fibroblast growth factor (bFGF), interleukin (IL)-1β, bone morphogenetic protein (BMP)-2, and BMP-7 were determined by enzyme-linked immunosorbent assay.Results: Pain strength showed a highly significant association with intra-articular IGF-1 levels (ρ =.48, P