Alendronate in the Prevention of Collapse of Femoral Head in Non-Traumatic Osteonecrosis

Alendronate in the Prevention of Collapse of Femoral Head in Non-Traumatic Osteonecrosis

To determine the cumulative incidence of total hip replacement, time to event after treatment with Fosamax or placebo during the study peroid

To determine the cumulative incidence of total hip replacement and collpase of femoral head, time to event after treatment with Fosamax or placebo during the study peroid

Inclusion Criteria:

• osteonecrosis of femoral head
• be able to provide singed informed consent

Exclusion Criteria:

• prior bisphosphonate use
• pregnant or lactating woman
• bilateral hip replacement