Tag Archive | alendronate

Preventing Atypical Femoral Fractures Related to Bisphosphonates

Physicians worldwide frequently prescribe bisphosphonates such as alendronate (Fosamax) and ibandronate (Boniva) to treat osteoporosis and prevent fragility fractures. Unfortunately, long-term bisphosphonate use has been linked to an increased risk of atypical femoral fractures. In the March 3, 2015 edition of JBJS Reviews, Blood et al. offer some guidance on how to prevent such fractures.

The authors note that prodromal thigh pain and a radiolucent line on X-rays of patients with a history of chronic bisphosphonate use are strong indicators of an impending fracture. Among bisphosphonate users who have an incomplete fracture with little or no pain, the authors recommend a trial of discontinued bisphosphonates, protected weight-bearing, calcium and vitamin-D supplementation, and possible teriparatide (Forteo) therapy. They add that prophylactic fixation should be considered if there is no radiographic or symptomatic improvement after two to three months of that conservative approach. Blood et al. further recommend that patients at high risk for atypical femoral fracture, should consider discontinuing bisphosphonate therapy after five years of continuous use. They also encourage orthopaedists to assess the contralateral femur for signs of impending fracture in patients who have already had an atypical femoral fracture.

The recommendations by Blood et al. notwithstanding, we should stress that the absolute risk of atypical femoral fractures fractures is low (3.2 to 50 cases per 100,000 person-years among short-term bisphosphonate users and about 100 cases per 100,000 person-years among long-term users). Consequently, for most people with osteoporosis, the proven fragility-fracture risk-reduction benefits of bisphosphonates outweigh the risks of atypical femoral fracture.

Readers interested in this subject may want to read a related Case Connections article, which springboards from a January 14, 2015 Case Connector article.

Another Look at Bisphosphonates and Jaw Osteonecrosis

A recent study in the Journal of Clinical Endocrinology & Metabolism found that approximately one out of 200 Taiwanese who used oral alendronate long term for osteoporosis developed osteonecrosis of the jaw (ONJ). In comparison, among a group treated with raloxifene for osteoporosis, only one out of 1,882 developed ONJ. Risk factors for developing ONJ among alendronate users included diabetes, RA, and exposure to the drug for more than three years.

Although this study reinforces an association between oral bisphosphonates and jaw osteonecrosis, it also demonstrates that this adverse effect is uncommon. While the incidence of ONJ in this study was 7 times higher with alendronate than with raloxifene, the incidence rate of ONJ attributed to alendronate use was only 283 per 100,000 persons per year. The increased relative risk with alendronate is worth noting, but the absolute risk remains low, and for people with osteoporosis, the fracture risk-reduction benefits of bisphosphonates continue to outweigh the risk of jaw osteonecrosis.