Background: Periprosthetic bone loss following total joint
arthroplasty may threaten the survival of the implant. Bisphosphonates are
effective in reducing bone loss in conditions associated with accelerated bone
turnover. To determine the current understanding of the effect of
bisphosphonates on periprosthetic bone mineral density after total joint
arthroplasty, we conducted computerized searches for randomized controlled
trials evaluating the use of bisphosphonates in patients treated with primary
total joint arthroplasty.
Methods: We searched MEDLINE, EMBASE, the Cochrane Central Register
of Controlled Trials, the Cochrane Database of Systematic Reviews, the web
site of the United Kingdom National Research Register, and the archives of the
American Academy of Orthopaedic Surgeons annual meetings (1989 through 2003),
and we conducted hand searches of the bibliographies of relevant articles. We
assessed methodological quality and abstracted relevant data. When necessary,
we contacted authors to provide additional information.
Results: Of 386 citations that were initially identified, six (five
complete papers and one abstract), which included a total of 290 patients, met
our inclusion criteria. Those papers showed that significantly less
periprosthetic bone loss had occurred in the bisphosphonate-treated patients
than in the control patients at three months (152 patients; weighted mean
difference, 3.3%; 95% confidence interval, 1.9% to 4.7%; p < 0.01), six
months (248 patients; weighted mean difference, 4.5%; 95% confidence interval,
1.6% to 7.4%; p < 0.001), and twelve months (197 patients; weighted mean
difference, 4.2%; 95% confidence interval, 1.5% to 6.9%; p = 0.03).
Bisphosphonates appeared to have a larger effect on bone loss following
arthroplasties with cement than on bone loss following arthroplasties without
cement (difference, 0.1%, 5%, and 5.4% at three, six, and twelve months;
significant difference [p < 0.001] at one year only) and a larger effect on
bone loss following total knee arthroplasties than on bone loss following
total hip arthroplasties (difference, 4.1%, 11.5%, and 7.1% at three, six, and
twelve months; significant difference [p < 0.001] at six months only). None
of the studies related the effects of bisphosphonates on bone mineral density
to clinically relevant outcomes.
Conclusions: A meta-analysis of six randomized controlled trials
suggested that bisphosphonates have a beneficial effect with regard to
maintaining more periprosthetic bone mineral density than that in controls.
However, the limitations of the available studies and the lack of analyses of
clinically relevant outcomes (functional outcomes, revision rates, and quality
of life) necessitate the planning and conduct of a sufficiently sized,
methodologically sound study with clinically relevant end points. Until this
has been done, the current evidence regarding the beneficial effects of
bisphosphonates on periprosthetic bone after total joint arthroplasty should
be interpreted with caution.
Level of Evidence: Therapeutic Level I. See Instructions
to Authors for a complete description of levels of evidence.