Bone quality and bone strength: benefits of the bone-forming approach.

The ability of bone to resist fracture depends on the intrinsic properties of the materials that comprise the bone matrix mineralization, the amount of bone (i.e. mass), and the spatial distribution of the bone mass (i.e. microarchitecture). Antiresorptive agents may prevent the decay of cancellous bone and cortical thinning, with no improvement of bone microstructure, leading to a partial correction of the principal bone quality defect in osteoporosis, the disruption of trabecular microarchitecture. Anabolic agents promote bone formation at both trabecular and endocortical surfaces, resulting in an increase of cancellous bone volume and cortical thickness. The improvement of cortical bone strength may be limited by an increase in cortical porosity. strontium ranelate improves trabecular network and cortical thickness that will contribute to anti-fracture efficacy at both vertebral and non-vertebral sites. The results of clinical and experimental studies are consistent with the mode of action of strontium involving dissociation between bone formation and resorption leading to a stimulation both trabecular and cortical bone formation without increasing cortical porosity.

Osteoporosis drugs in real-world clinical practice: an analysis of persistence.

The aim of our retrospective cohort study is to analyze the persistence rates in relation to antiosteoporotic drugs using administrative databases in the Campania Region. Patients, aged ≥40 years, were included if at least one prescription for any antiosteoporotic drugs had been filled in between January 1, 2009 and December 31, 2009. Overall, 37,594 patients were incident users of antiosteoporotic drugs. Among them, 15,978 patients had undergone spot-therapies. A total of 2,618 (14.1%) were classified as switchers. Switching rates were highest for patients taking Alendronate 18.9 or Strontium Ranelate 15.0 and lower for patients taking Ibandronate 12.8 or Risedronate 10.8. In the overall population, 33.5% of subjects were still on therapy after 6 months. At 1 year, persistence rates were: Ibandronate 21.6%, Risedronate 15.8%, Alendronate + Vitamin D 15.7%, Raloxifene 14.3%, Alendronate 12.6% and Strontium Ranelate 5.0%.

Periprosthetic bone density as outcome of therapeutic response.

The bone surrounding a prosthetic implant normally experiences a progressive quantitative reduction as a result of stress shielding and wear debris production, that can lead to the aseptic loosening of the implant. Dual-energy X-ray absorptiometry (DXA), using software algorithms, can ensure a surrogate measure of load redistribution after the implant of the prosthetic components and can be a valid tool to evaluate the efficacy of pharmacological therapy to reduce the periprosthetic bone loss. In several animal and human studies DXA has been able to quantify antiresorptive action of bisphosphonates in the periprosthetic area.