Update on the use of zoledronic acid in the management of osteoporosis

Minor post-extraction complications other than BRONJ in older patients on oral bisphosphonates - a retrospective study

BACKGROUND

Oral bisphosphonates (BP) have been prescribed widely in osteoporosis patients. Bisphosphonate-related osteonecrosis of the jaw (BRONJ) has been reported as a major complication, but there is little information about minor complications.

OBJECTIVE

This retrospective study describes post-operative complications - other than BRONJ - associated with dental extractions in patients on oral BP and compares outcomes with patients not on oral BP.

METHODS

The study period was 2004-05 ending December 2005, prior to the introduction of protocols for minimising risks related to extractions in patients on BP therapy. Records of patients aged 60 years and over who underwent extractions during this period at Sydney Dental Hospital were examined and post-operative complications analysed.

RESULTS

There were 266 participants identified on oral BP therapy out of an available number of 3811 available files based retrospectively from records of 4126 participants who underwent extractions during the two-year period. In the oral BP group, 10% had complications compared with 2% in the non-oral BP group (p < 0.0001). This relationship remained significant even after adjusting for age, gender, operator, type and site of procedure. Delayed healing (36%) and exposed alveolar bone which required an intervention (31%) were the most common complications in the BP group.

CONCLUSION

The prevalence of minor post-operative complications among BP participants was significantly higher than in non-BP participants. The nature of the complications was in the range of pathology familiar to - and treatable by - the general dentist.

Zoledronic acid suppresses callus remodeling but enhances callus strength in an osteoporotic rat model of fracture healing

MINI-ABSTRACT

In this study, we demonstrated that the use of zoledronic acid does not impair fracture healing, but results in superior callus size and resistance at the fracture site, which could be the consequence of a lower rate of bone turnover due to its anti-catabolic effect.

OBJECTIVE

To investigate the effect of inhibition of bone remodeling by the bisphosphonate, zoledronic acid, on callus properties in an osteoporotic rat model of fracture healing.

METHODS

Ovariectomized (OVX) rats were randomly divided into four treatment groups (n=24 per group): saline control (CNT); and three systemic zoledronic acid-injected groups (0.1mg/kg), administered 1 day (ZOLD1), 1 week (ZOLW1), and 2 weeks (ZOLW2) after fracture. Rats were killed at either 6 or 12 weeks postoperatively. Postmortem analyses included radiography, microcomputed tomography, histology, histomorphometry, biomechanical tests, and nanoindentation tests.

RESULTS

Treatment with zoledronic acid led to a significant increase in trabecular bone volume within the callus, as well as in callus resistance, compared to those in the saline control rats; delayed administration (ZOLW2) reduced intrinsic material properties, including ultimate stress and elastic modulus, and microarchitecture parameters, including bone volume/total volume (BV/TV), trabecular thickness (Tb.Th), and connectivity density (Conn.D), compared with ZOLD1 at 12 weeks after surgery. OVX had a negative effect on the progression of endochondral ossification at 6 weeks. Zoledronic acid administration at an early stage following fracture may bind to early callus, and thus not affect subsequent callus formation and endochondral ossification, while delayed administration (ZOLW2) mildly suppresses bony callus remodeling.

CONCLUSION

The superior results obtained with zoledronic acid (ZOLD1, ZOLW1, and ZOLW2) compared to CNT in terms of callus size and resistance could be the consequence of a lower rate of bone turnover at the fracture site due to the anti-catabolic effect of zoledronic acid. Mild suppression of callus remodeling by delayed administration did not impair the initial phase of the fracture healing process.

Role of bisphosphonates in the management of postmenopausal osteoporosis: an update on recent safety anxieties

Following their introduction in the 1990s, bisphosphonates have become the mainstay of treatment in the management of postmenopausal osteoporosis, and their use continues to rise. Commonly noted adverse effects in clinical practice include gastrointestinal side-effects, acute phase reactions (predominately seen with intravenous preparations) cutaneous reactions and more rarely, ocular side-effects. However, recent reports of potentially serious adverse effects of bisphosphonate therapy, including atypical subtrochanteric and femoral shaft fractures, atrial fibrillation, oesophageal carcinoma and osteonecrosis of the jaw, have prompted concerns regarding the long-term safety of this class of drugs. This review summarizes the benefits and potential adverse effects of bisphosphonates used in the treatment of postmenopausal osteoporosis. Although evidence of a definitive casual relationship between bisphosphonate therapy and serious adverse effects is lacking, concern remains particularly in relation to atypical subtrochanteric and femoral shaft fractures. This has important consequences in terms of determining optimum duration of therapy and how best to target therapy at those most at risk. Recently, attention has focused on individual fracture risk assessment in order to optimize the risk-benefit ratio of treatment for individual patients. A review of the role of hormone replacement therapy in younger women with significant risk of osteoporotic fractures may be timely in these circumstances.