OBJECTIVES: Periprosthetic bone mineral density (PBMD) loss is a common outcome after hip arthroplasty (HA). Previously published meta-analyses have confirmed a protective effect of bisphosphonates on PBMD after HA but no direct comparison on the effect of different bisphosphonates has been conducted. Therefore, we conducted an indirect treatment comparison (ITC) to evaluate the effects of different bisphosphonates on PBMD.

METHODS: A systematic literature search in Embase, Medline, and Cochrane CENTRAL using the Ovid platform was conducted to identify randomized controlled trials (RCTs) comparing bisphosphonates versus placebo/no-treatment/others in PBMD loss after HA. Weighted mean differences (WMD) with 95% confidence interval (CI) were calculated to evaluate the effect of bisphosphonates on PBMD. Indirect estimates of alendronate and zoledronic acid versus other bisphosphonates were calculated according to the results of their direct comparisons with a common control from the random effect meta-analysis.

RESULTS: However, results from ITC showed no significant improvement in PBMD with alendronate and zoledronic acid versus other bisphosphonates at 12 months and 2-4 years though zoledronic acid showed numerically higher mean difference (range: 0.14 to 0.19) in terms of PBMD improvement (12 months).

CONCLUSIONS: Meta-analysis of RCTs found that alendronate and zoledronic acid showed significant improvement in PBMD in patients with HA versus control. However, ITC results found no significant differences for PBMD among the bisphosphonates. The results should be interpreted with caution owing to low sample size and heterogeneity in the included population. Further direct head to head trials with long term follow up are warranted.