Knee osteoarthritis, knee joint pain and aging in relation to increasing serum hyaluronan level in the Japanese population

SummaryObjectiveTo investigate relationship between serum hyaluronan (HA) level and the presence and severity of radiographic knee osteoarthritis (OA) as well as degree of knee pain in Japanese population.DesignA total of 616 volunteers participated in this study. Based on the Kellgren–Lawrence (K–L) grade, participants were radiographically classified into three groups: Normal (K–L grade 0 or 1), Moderate (grade 2) and Severe (grade 3 or 4). The degree of knee pain was quantified by visual analogue scale (VAS) and Knee injury and Osteoarthritis Outcome Score (KOOS) Pain. Serum HA levels were compared among the Normal, Moderate and Severe groups, and the relationship between serum HA level and the severity of knee OA was analyzed after age, sex and body mass index (BMI) were adjusted. In addition, the correlation between serum HA level and the degree of knee pain was analyzed in each group.ResultsRegarding relationship between serum HA level and the severity of radiographic knee OA, serum HA levels of the Moderate and Severe groups were significantly higher than in the Normal group (P < 0.001). Furthermore, serum HA level correlated with the severity of radiographic knee OA (r = 0.289, P < 0.001) after adjusting for age, sex and BMI. Serum HA level correlated with VAS of knee pain and/or KOOS Pain in the Normal and Moderate groups.ConclusionSerum HA level has the potential to be useful for the diagnosis of the presence and severity of knee OA.