https://immattersacp.org/weekly/archives/2011/12/13/5.htm

Bisphosphonate use associated with extended implant survival in knee, hip replacements

Bisphosphonate use was associated with an almost twofold increase in implant survival time in patients undergoing lower limb arthroplasty, researchers found.


Bisphosphonate use was associated with an almost twofold increase in implant survival time in patients undergoing lower limb arthroplasty, researchers found.

Researchers conducted a population-based retrospective cohort study using data from the General Practice Research Database of 3 million primary care patients in the United Kingdom. They identified all patients over the age of 40 undergoing knee (n=18,726) or hip (n=23,269) replacement surgery from 1986-2006 for osteoarthritis. Bisphosphonate users were defined as patients with at least six prescriptions of bisphosphonates or at least six months of prescribed bisphosphonate treatment with more than 80% adherence before surgery. Patients were excluded for a history of hip fracture before surgery or rheumatoid arthritis and for being younger than 40 years of age at surgery. Results were published Dec. 6 at BMJ.

Of the nearly 42,000 patients, 1,912 took bisphosphonates. They had a lower rate of revision at five years than non-users: 0.93% (95% CI, 0.52% to 1.68%) versus 1.96% (95% CI, 1.80% to 2.14%).

At five-year follow-up, 522 (1.2%) participants had revision surgery. There were 511 (1.3%) revisions (296 hip and 215 knee) in non-users of bisphosphonates. There were only 11 (0.6%) revisions in bisphosphonate users—eight hip and three knee. Bisphosphonate use had a strongly protective effect on implant survival throughout the study (adjusted hazard ratio 0.54; 95% CI, 0.29 to 0.99; P=0.047), with a significant increase in median prosthesis survival (time ratio 1.96; 95% CI, 1.01 to 3.82).

Assuming an accumulated incidence of failure of 2% over five years, researchers calculated that the number needed to treat to avoid one revision was 107 for patients ages 40 years or older.

“If, in addition to fracture reduction, bisphosphonate use leads to a reduced risk of implant failure and therefore an extension of implant survival, its use should be assessed in clinical settings,” the researchers wrote. “If these findings are replicated in other observational cohorts, a randomized clinical trial is needed to test the efficacy and cost effectiveness of bisphosphonate use at or before the time of surgery to improve implant survival and reduce fracture risk.”