Bisphosphonate Use in Patients Who Have Osteoporosis Does Not Increase the Risk of Periprosthetic Fracture Following Total Knee Arthroplasty.

Background: The purpose of this study was to evaluate the effect of preoperative bisphosphonate use in patients who have osteoporosis on the risk of complications following primary total knee arthroplasty (TKA).

Methods: An administrative claims database was queried for patients who have osteoporosis undergoing primary TKA between 2010 and 2019 with a minimum of 2-year follow-up. Bisphosphonate-naive patients and bisphosphonate users, defined as patients who had a continuous prescription for bisphosphonates for a minimum of 6 months preoperatively, were matched 1:1 based on age, sex, and comorbidity burden. Patients undergoing nonelective TKA on chronic glucocorticoid therapy or receiving any other pharmacologic treatment for osteoporosis were excluded. The final cohort included 21,058 matched pairs of patients. The incidence of postoperative complications was identified via International Classification of Disease coding and compared between matched groups. A subgroup analysis was performed to examine outcomes among patients who underwent cemented and cementless TKA.

Results: There was no difference in the incidence of periprosthetic fracture on univariate (0.7 versus 0.8%, P = 0.068) or multivariate testing (OR [odds ratio]: 1.24, 95% confidence interval [0.99 to 1.56]; P = 0.060). Bisphosphonate users were statistically less likely to undergo all-cause revision TKA at 2 years (OR: 0.84 [0.72 to 0.97]; P = 0.021). Patients who had osteoporosis were found to have an increased risk of periprosthetic fracture when TKA was performed with cementless implants (1.6 versus 0.4%; P = 0.033). However, when treated with bisphosphonates, patients who have osteoporosis demonstrated equivalent fracture rates regardless of implant type (1.3 versus 1.0%; P = 1.000).

Conclusions: While bisphosphonate use in patients who have osteoporosis did not decrease the risk of periprosthetic fracture, it did significantly lower the incidence of all-cause revision at 2 years, although the difference identified was small. Consideration should be given to performing cemented TKA in patients who have untreated osteoporosis, given the higher rate of periprosthetic fracture when cementless implants were utilized.