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SAN FRANCISCO -- Total hip arthroplasty (THA) is largely performed in older people, among whom osteoporosis is common and can increase risks for complications down the line. Yet while it may seem obvious that THA candidates should therefore be screened for osteoporosis, they seldom are, according to a study reported here.

Patient records in the PearlDiver healthcare claims database for 2010-2021, covering over 150 million Americans, indicated that out of some 380,000 people undergoing THA who had no pre-existing osteoporosis diagnosis, 53% had at least one risk factor for osteoporosis -- but only 12.4% of these at-risk individuals underwent screening with dual-energy x-ray absorptiometry (DEXA) scans prior to having the procedure.

And those at-risk patients suffered significantly increased rates of periprosthetic and fragility fractures -- to which bone mineral loss is a key contributor -- relative to those without osteoporosis risk factors, Amil Agarwal, BA, a 4th-year medical student at George Washington University in Washington, D.C., told attendees at the American Academy of Orthopaedic Surgeons' annual meeting.

Osteoporosis screening should not be a heavy lift in the surgery center, he pointed out. He said a simple questionnaire about risk factors, given when patients are first evaluated for THA, could then trigger DEXA scan orders when a patient checks enough boxes.

Agarwal and colleagues weren't especially surprised by their findings, however, insofar as a appeared in 2019, prompting the new research. In that study, conducted at a single center with 200 joint replacement patients (knee and hip), more than half should have qualified for DEXA screening but only 18% of them actually received it. (Additionally, fewer than one-quarter of patients eligible for osteoporosis treatment actually received it; that issue was not addressed in the new study.) And, Agarwal observed, screening rates in the general population are very low.

Because of the earlier work's limitations, Agarwal and colleagues believed a nationwide examination was warranted. The included information on seven parameters considered risk factors for osteoporosis, any one of which is sufficient to warrant a DEXA scan: age 65-plus for women or 70-plus for men, metabolic conditions, tobacco use, prior fragility fracture, low body mass, history of chronic steroids, and alcohol use disorder. Patients with records of a DEXA scan in the 3 years prior to THA were counted as having been screened.

Some of these risk factors appeared more likely than others to trigger DEXA screening. Among patients who had been on long-term steroids, for example, 27% had been screened; the prevalence was 19% for women 65 and older. At the other end, just 2% of men 70 and older were screened. Perhaps more alarmingly, only 7% of patients with previous fragility fractures had been screened.

The records also indicated that, among patients with at least one osteoporosis risk factor, 0.9% experienced a periprosthetic fracture and about 1.3% had a fragility fracture within 5 years after THA. These rates were approximately double those seen in low-risk patients.

Limitations to the study included the exclusion of patients whose records indicated an osteoporosis diagnosis or prescription for an osteoporosis drug prior to THA, as well as the reliance on administrative data.

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