Preoperative vertebral fracture assessment reveals bone fragility missed by DXA in patients undergoing total hip arthroplasty.

backgroundBone fragility assessment prior to total hip arthroplasty (THA) is typically based on bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA). Meanwhile, prevalent vertebral fracture (VF), an important indicator of bone fragility, may be present even when BMD does not meet the diagnostic criteria for osteoporosis. Although preoperative bone health assessment has become crucial in patients undergoing THA, VFs remain insufficiently evaluated. This study aimed to investigate the prevalence and distribution of DXA-defined osteoporosis and VFs in patients undergoing THA and to evaluate how often DXA alone fails to detect clinically relevant bone fragility.

methodsThis retrospective observational study included all consecutive patients aged ≥ 45 years who underwent primary THA between January 2021 and December 2025. Those undergoing THA for non-osteoarthritis etiologies were excluded. BMD was measured at the lumbar spine and femoral neck using DXA, and prevalent VFs were assessed on preoperative lateral thoracolumbar radiographs using Genant's semi-quantitative method. DXA-defined osteoporosis was defined as a T-score ≤ - 2.5 at any measured site. Clinical osteoporosis was defined as DXA-defined osteoporosis and/or VF. The prevalence and distribution of DXA-defined osteoporosis, VF, and their overlap were assessed. Multivariable logistic regression analysis adjusted for age, sex, body mass index, and contralateral hip status was performed to identify factors associated with VF without DXA-defined osteoporosis.

resultsAmong the 352 included patients, DXA-defined osteoporosis was identified in 84 (23.9%) and VFs in 59 (16.8%). Clinical osteoporosis was observed in 118 patients (33.5%). Of these, 34 patients (9.7% of the total cohort; 28.8% of those with clinical osteoporosis) had VFs without DXA-defined osteoporosis and would not have been identified using DXA alone. Advanced age was independently associated with VF without DXA-defined osteoporosis (adjusted odds ratio, 2.65 per 10-year increase; 95% confidence interval, 1.65-4.24). In patients aged 80 years or older, the prevalence of VF without DXA-defined osteoporosis was 30.6%, and that of clinical osteoporosis was 58.3%.

conclusionsDXA alone underestimated clinically relevant bone fragility in patients undergoing THA. Preoperative radiographic evaluation of VF may improve bone fragility assessment, particularly in older patients.