Association between urinary C-telopeptide fragments of type II collagen and knee structure in middle-aged women without clinical knee disease

SummaryObjectiveThere is evidence for an association between levels of urinary C-telopeptide fragments of type II collagen (uCTX-II) and risk of knee osteoarthritis (OA). The aim of this cohort study was to examine the association between uCTX-II levels and knee cartilage and bone changes in middle-aged women without clinical knee disease.Design140 women, aged 40–67 years, with no significant knee pain, knee injury or any forms of arthritis, underwent knee magnetic resonance imaging (MRI) at baseline and 2 years later. Cartilage volume, cartilage defects, tibial plateau bone area and bone marrow lesions (BMLs) were measured using validated methods. Baseline uCTX-II was measured using enzyme-linked immunosorbent assay (ELISA).ResultsFor every one unit (natural logarithm transformed) increase in baseline uCTX-II level, there was an increase in the prevalence of medial tibiofemoral cartilage defects (Odds ratio (OR) 4.36, 95% confidence interval (CI) 1.58–12.04), medial (80.2 mm2, 95% CI 9.3–151.1) and lateral (86.0 mm2, 95% CI 33.3–138.7) tibial plateau bone area, and the prevalence of lateral tibiofemoral BMLs (OR 10.62, 95% CI 1.82–61.85). Baseline uCTX-II levels were not significantly associated with baseline tibial cartilage volume or changes in knee cartilage volume or defects or bone area over 2 years, although there was a trend for the deterioration of medial tibiofemoral BMLs (P = 0.06).ConclusionIn middle-aged women without clinical knee disease, higher uCTX-II levels were associated with early detrimental structural changes at the knee (cartilage defects, tibial bone expansion and BMLs) at baseline but not over 2 years. Further work will be needed to determine its sensitivity to change and whether it predicts disease progression over longer time periods