Opportunistic CT assessment of psoas muscle attenuation and its association with lumbar osteoporosis in total hip arthroplasty candidates.

Abstract

To assess the association between opportunistically derived CT measures of psoas muscle quality and lumbar osteoporosis in patients undergoing total hip arthroplasty. This retrospective cohort study included 220 total hip arthroplasty candidates who underwent preoperative lumbar dual-energy X-ray absorptiometry and unenhanced CT at L3. Psoas muscle attenuation, psoas muscle index, and vertebral trabecular attenuation were quantified using standardized protocols. Multivariable logistic regression was used to evaluate associations with lumbar osteoporosis (T-score < -2.5), adjusting for age, sex, and body mass index. The association between preoperative psoas muscle attenuation and postoperative Hip Disability and Osteoarthritis Outcome Score-Joint Replacement was examined using multivariable linear regression adjusting for baseline score. Lumbar osteoporosis was present in 71 patients (32%). After adjustment, each 10-HU decrease in psoas muscle attenuation (adjusted odds ratio 1.28, 95% confidence interval 1.05-1.56, P = 0.024) and vertebral trabecular attenuation (adjusted odds ratio 1.21, 95% confidence interval 1.05-1.39, P = 0.035) was associated with higher odds of osteoporosis. At a median follow-up of 24 months (interquartile range, 16-33 months), higher preoperative psoas muscle attenuation was independently associated with higher postoperative Hip Disability and Osteoarthritis Outcome Score-Joint Replacement score (β = 1.02 per 1-HU increase, 95% confidence interval 0.62-1.43, P = 0.018). Lower psoas muscle attenuation on opportunistic CT was associated with lumbar osteoporosis and postoperative functional outcomes in patients undergoing total hip arthroplasty. These findings support the potential role of CT-derived attenuation metrics as complementary markers in preoperative evaluation.