Abstract
Introduction and Aims: Periprosthetic bone loss is responsible for the majority of cases of implant failure after total joint arthroplasty. Bisphosphonates are effective in reducing bone loss in many conditions associated with accelerated bone turnover. Our aim was to determine the effect of bisphosphonates on periprosthetic bone mineral density (BMD, g/cm2) after total joint arthroplasty.
Method: We conducted computerised searches for randomised controlled trials, evaluating the effects of bisphosphonates on periprosthetic bone mineral density in patients undergoing primary total joint arthroplasty. We searched MEDLINE, EMBASE, CINAHL, the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews and the United Kingdom National Research Register Web-site to November 2003. Computerised searches of the archives of AAOS Annual Meetings 1989–2003 were also conducted. Additional strategies to identify articles included a hand search of the bibliographies of relevant articles and direct contact with the authors.
Results: Of 386 citations initially identified, nine citations met our eligibility criteria. The total number of randomised controlled trials was six (five published and one abstract). Four trials evaluated total hip arthroplasty and two examined total knee arthroplasty. Five trials used alendronate and one used pamidronate. Quality scores ranged from 65 to 75. The pooled sample size was 290 patients. Less periprosthetic bone loss occurred in the intervention group compared to the control group at the following follow-up intervals: three months (n=128, Weighted Mean Difference (WMD): 3.3%, 95% Confidence Interval (CI): 1.9–4.7, p< 0.01); six months (n=224, WMD: 4.5%, CI: 1.6–7.4, p< 0.001); and 12 months (n=173, WMD: 4.2%, CI: 1.5–6.9, p=0.03). Tests of heterogeneity revealed greater maintenance of BMD in cemented arthroplasty than in uncemented arthroplasty (WMD: 7.5%, CI: 4.3–10.7 versus WMD: 2.1%, CI: 0.61–3.6, respectively, p< 0.001) at 12 months follow-up.
Conclusion: Bisphosphonates have a beneficial effect on maintaining periprosthetic bone stock compared to control after total joint arthroplasty. The effect seems greater in cemented arthroplasty and total knee arthroplasty. Whether this increase in BMD results in improved fixation and longevity of prosthetic components remains unanswered. Larger trials evaluating the effect of bisphosphonates on rates of implant loosening and functional outcomes are needed.
These abstracts were prepared by Editorial Secretary, George Sikorski. Correspondence should be addressed to Australian Orthopaedic Association, Ground Floor, The William Bland Centre, 229 Macquarie Street, Sydney, NSW 2000, Australia.
None of the authors is receiving any financial benefit or support from any source.
