Imbalanced bone turnover markers and low bone mineral density in patients with osteonecrosis of the femoral head

Purpose: There have been few studies investigating the cumulative effect of individual factors related to bone metabolism on the systemic balance between bone formation and resorption in patients with osteonecrosis of the femoral head (ONFH). We investigated bone mineral density (BMD) of lumbar spine and bone turnover markers that reflect systemic bone metabolism. Methods: Two-hundred twenty patients with ONFH were matched to 220 healthy subjects according to age, gender, and body mass index. ONFH patients were divided into steroid-induced (18%), alcoholic (21%), and idiopathic ONFH (61%) and subgroup analysis was performed to exclude the effect of steroid and malnutrition on bone metabolism. We compared lumbar spine bone mineral density (BMD) between groups and measured serum bone-specific alkaline phosphatase (BALP) and urinary deoxypyridinoline/creatinine (Dpd/Cr) ratio. Results: Logistic regression analysis revealed low spine BMD was significantly associated with each subgroup of ONFH when compared with that of the control group (odds ratio of 2.27, 4.24, and 1.86 in alcoholic, steroid, and idiopathic ONFH, respectively). The mean value of serum BALP (27.02 U/L) was within the normal reference range while average urine Dpd/Cr ratio (6.24 nM/mM) increased in ONFH group when compared with respective reference range. Conclusion: Spine BMD decreased and urinary Dpd/Cr ratio increased in patients with non-traumatic ONFH. Further studies will be necessary to identify whether non-traumatic ONFH is merely a regional disease confined to the femoral head or may affect systemic bone metabolism.