Bihlet AR, Byrjalsen I, Bay-Jensen A, et al. - Baseline data of two randomized clinical trials in patients with radiographic OA and presence of pain were investigated post hoc in order to examine the relationship between OA knee joints at various radiographic stages and pain classes with levels of uCTX-II and biomarkers of bone resorption and formation. Levels of uCTX-II were independently correlated with the radiographic severity of OA and pain intensity. CTX-II was related to weight-bearing pain, though not with non-weight-bearing pain, independent of covariates. According to the radiographic severity of single joints, Bilateral OA knee joints seemed to contribute to uCTX-II levels in an incremental manner. Thus, the data imply that biomarker variations between genders should be considered when assessing these markers in the context of structural features of OA.