Joint biomarkers in idiopathic femoral head osteonecrosis: Comparison with hip osteoarthritis

Objective. To compare concentrations of joint biomarkers in synovial fluid (SF) between idiopathic osteonecrosis of the femoral head (ION) and osteoarthritis (OA) of the hip joint. Methods. Levels of the joint biomarkers cartilage oligomeric matrix protein (COMP), antigenic keratan sulfate (AgKS), and hyaluronan (HA) in SF samples from 21 cases of ION and their relationship to disease stage and history of steroid use were assessed and compared to the result of 29 cases of hip OA. Results. In both the ION and hip OA groups, levels of COMP and AgKS in SF showed a significant positive correlation. The ION group had significantly higher levels of AgKS in SF than the hip OA group. In the ION group, stage II patients had significantly higher SF levels of both COMP and AgKS than those in stage III patients. No difference in level of HA in hip joint SF was found between steroid and non-steroid treated ION patients or between the stage II and III subgroups. Conclusion. SF levels of COMP and AgKS may serve as useful joint biomarkers that reflect cartilage metabolism not only in hip OA but also in ION.