Systemic Osteoporosis and Osteopenia Among Periprosthetic Fractures After Total Hip Arthroplasty.

BACKGROUND

Most periprosthetic fractures following total hip arthroplasty (THA) are fragility fractures that qualify patients for osteoporosis diagnoses. However, it remains unknown how many patients were diagnosed who had osteoporosis before injury or received the proper evaluation, diagnosis, and treatment after injury.

METHODS

We identified 171 Vancouver B2 (109) and B3 (62) periprosthetic femur fractures treated with a modular fluted tapered stem from 2000 to 2018 at 1 institution. The mean patient age was 75 years (range, 35 to 94), 50% were women, and the mean body mass index was 29 (range, 17 to 60). We identified patients who had osteoporosis or osteopenia diagnoses, a fracture risk assessment tool (FRAX), bone mineral density (BMD) testing, an endocrinology consult, and osteoporosis medications. Age-appropriate BMD testing was defined as no later than 1 year after the recommended ages of 65 (women) or 70 years (men). The mean follow-up was 11 years (range, 4 to 21).

RESULTS

Falls from standing height caused 94% of fractures and thus, by definition, qualified as osteoporosis-defining events. The prevalence of osteoporosis diagnosis increased from 20% before periprosthetic fracture to 39% after (P < .001). The prevalence of osteopenia diagnosis increased from 13% before the fracture to 24% after (P < .001). The prevalence of either diagnosis increased from 24% before fracture to 44% after (P < .001). No patients had documented FRAX scores before fracture, and only 2% had scores after. The prevalence of BMD testing was 21% before fracture and 22% after (P = .88). By the end of the final follow-up, only 16% had received age-appropriate BMD testing. The proportion of patients who had endocrinology consults increased from 6% before the fracture to 25% after (P < .001). The proportion on bisphosphonate therapy was 19% before fracture and 25% after (P = .08).

CONCLUSIONS

Although most periprosthetic fractures following THA are fragility fractures that qualify patients for osteoporosis diagnoses, there remain major gaps in diagnosis, screening, endocrinology follow-up, and treatment. Like nonarthroplasty fragility fractures, a systematic approach is needed after periprosthetic fractures.

LEVEL OF EVIDENCE: Level III, retrospective cohort study.