In premenopausal women, bone mineral density and the biomarkers of joint metabolism are linked with early osteoarthritis of the knee. 

This assessment aimed to explore the association of joint metabolism biomarkers and BMD with early knee osteoarthritis in men and premenopausal women below the age of fifty years.

The study recruited 189 subjects (age below 50 years) with early knee osteoarthritis and 152 healthy subjects. Evaluation of the levels of bone biomarkers (procollagen type I N-terminal propeptide [PINP], osteocalcin, and C-terminal telopeptide of type 1 collagen [CTX-I]) and cartilage biomarkers (N-propeptide of collagen IIA [PIIANP], cartilage oligomeric matrix protein [COMP], CTX-II, and matrix metalloproteinase-3 [MMP-3]) was done.

BMD was estimated at the hip, lumbar, and femoral neck. For determining the association between biomarkers, BMD, and early knee osteoarthritis, multivariate regression analyses were carried out.

In comparison with the control group, a rise in serum COMP, urine CTX-II and BMD at the femoral neck and hip were noted while a decline in serum PINP and osteocalcin was noted in the premenopausal women.

The serum PINP demonstrated a negative link with premenopausal early knee osteoarthritis, while  urine CTX-II, serum COMP, and BMD at femoral neck and hip demonstrated a positive link. But, in male participants, only serum COMP was noted to be greater than control and no link of biomarkers or BMD was reported with early knee osteoarthritis.

BMD and the biomarkers demonstrated multiple links with early knee osteoarthritis in premenopausal women, but not in men aged below fifty years. Sex differences should be considered when assessing cartilage and bone metabolism in early osteoarthritis of the knee.