The Association of Postoperative Osteoporosis Therapy With Periprosthetic Fracture Risk in Patients Undergoing Arthroplasty for Femoral Neck Fractures

Displaced femoral neck fractures in older adults are generally treated with hip arthroplasty. One concern following hip arthroplasty is the risk for periprosthetic fractures (PPFs). Most patients who have hip fractures are candidates for antiosteoporotic therapy, but the impact of this treatment on PPFs is unknown. Therefore, the primary objective of this study was to evaluate whether patients treated with antiosteoporotic medical therapy had lower odds of PPFs following arthroplasty for hip fracture.Patients at least 65 years old who underwent hip arthroplasty for femoral neck fractures from 2010 to 2020 were identified in a national database. Patients were stratified based on whether they initiated antiosteoporotic therapy within 1 year of hip arthroplasty. Minimum follow-up was 1 year, and maximum follow-up was 10.6 years. The primary endpoint was cumulative incidence of PPF as determined using Kaplan-Meier and Cox proportional hazards regression analyses. Overall, 2,026 patients who underwent arthroplasty for femoral neck fracture received antiosteoporotic medications within 1 year following surgery (mean follow up 4.8 years; range 1.0 to 10.6 years) and 33,639 patients did not (mean follow up 4.1 years; range 1.1 to 10.3 years).The 10-year cumulative incidence of PPF for patients treated for osteoporosis was 3.88% compared to 5.92% for those who were untreated (P < .001). Adjusting for covariates, patients who received osteoporosis treatment had a significantly lower risk for PPF than those who were untreated (hazard ratio (HR): 0.663; 95% confidence interval (CI): 0.465-0.861; P = .038).The present study suggests that osteoporosis treatment is associated with lower incidence of PPF following hip arthroplasty for femoral neck fractures. Treatment of osteoporosis should be initiated in eligible patients who sustain a femoral neck fracture, especially those who undergo hip arthroplasty.