The role of the serum RANKL/OPG ratio in the healing of intertrochanteric fractures in elderly patients

Intertrochanteric fractures occur most commonly in elderly patients. Osteoblasts and osteoclasts have been reported to be regulated by the receptor activator of NF-kappa B ligand (RANKL) and osteoprotegerin (OPG), during bone modeling and remodeling, respectively. Based on these observations, we hypothesized that the serum levels of RANKL, OPG and the RANKL/OPG ratio are important in the healing of intertrochanteric fractures in elderly patients. Enzyme-linked immunosorbent assays were used to measure the serum concentrations of RANKL and OPG in 36 elderly patients with intertrochanteric fractures and 30 age-matched healthy control subjects, at baseline and 4, 8 and 12 weeks following injury. The RANKL/OPG ratio in the two groups was also evaluated. Similar trends in RANKL and OPG levels were detected during the fracture healing process. The serum levels of RANKL and OPG were higher in the fracture group than in the controls, and were significantly higher at baseline and 4 weeks following injury (P < 0.05). Notably, although the RANKL/OPG ratio gradually increased during healing, it was lower in the fracture group than in the control group. The RANKL/OPG ratio was significantly lower immediately after and 4 weeks after injury in the fracture group (P < 0.05). Our data suggest a close correlation between higher serum levels of RANKL and OPG and the fracture healing process, indicating that RANKL and OPG are involved in fracture healing. The serum RANKL/OPG ratio also appears to be significant in the healing of intertrochanteric fractures in elderly patients.