Osteonecrosis or avascular osteonecrosis (AVN) of the femoral head is a devastating multifactorial disease that affects 20 000 persons each year in the United States. The purpose of this systematic review was to determine the efficacy and safety of alendronate for adult AVN during short- and long-term follow-up. Electronic databases were searched for randomized or nonrandomized clinical trials, cohort, case-control studies, and series of cases in which alendronate was used for treatment of adult AVN of the femoral head. Relevant articles with adequate data on reduction of pain, improvement of articular function, slowing of bone collapse progression, or need for total hip arthroplasty (THA) were included after applying inclusion and exclusion criteria. Eight articles involving 788 hips with evidence level 1b to 3b were included in this systematic review. Most studies suggested a positive short-term efficacy of alendronate treatment in reducing pain, improving articular function, slowing of bone collapse progression, and delaying the need for THA for adult AVN patients. The favorable long-term results were also presented in those treated patients after 10-year follow-up. In addition, there were no severe adverse effects associated with alendronate treatment observed during short- and long-term follow-up, and most of the included studies suggested use of alendronate in early AVN with small necrotic lesion to achieve better outcomes. The findings support consideration of alendronate use for adult AVN, particularly with early stage and small necrotic size. The lack of large-scale, randomized, and double-blind studies justifies new studies to demonstrate the detailed indication and the optimized strategy of alendronate treatment. Level of evidence: Level 3a.

Keywords: Adolescent, Alendronate - therapeutic use, Demography, Femur Head Necrosis - drug therapy, Time Factors, young adult