MRI-DERIVED POPLITEAL ARTERY WALL BIOMARKERS AND HIP OSTEOARTHRITIS: DATA FROM THE OSTEOARTHRITIS INITIATIVE

Vascular health has been implicated in OA pathogenesis, but evidence specific to hip OA remains limited. MRI-derived popliteal artery wall measurements, obtained opportunistically from knee MRI, may provide an imaging marker of systemic vascular burden and help characterize vascular-metabolic phenotypes relevant to hip OA and hip pain.

To evaluate whether baseline knee MRI-derived popliteal artery wall measurements are associated with prevalent and 4-year incident radiographic hip OA (rHOA), symptomatic hip OA (sHOA), and frequent hip pain in the Osteoarthritis Initiative.

This observational study included OAI participants with available baseline knee MRI and hip radiographs. Cross-sectional analyses included 8,506 hips, and longitudinal analyses included 6,224 hips with 4-year follow-up radiographs. Popliteal artery wall measurements were quantified from baseline knee MRI using an automated vessel-wall segmentation pipeline and included eccentricity ratio, mean normalized wall index (NWI), maximum NWI, and maximum wall thickness. Outcomes were prevalent and incident rHOA, sHOA, and frequent hip pain. Associations were assessed using multivariable logistic regression with cluster-robust standard errors to account for two hips within participants. Models were adjusted for age, sex, BMI, height, comorbidity score, smoking status, Physical Activity Scale for the Elderly, history of myocardial infarction or stroke, systolic and diastolic blood pressure, diabetes, and lipid-lowering medication use. ORs are reported per 1-SD increase in each vascular measurement.

At baseline, 521/8,506 hips (6.1%) had rHOA and 264/8,506 hips (3.0%) had sHOA. Mean age and BMI were 60.7 ± 9.1 years and 28.2 ± 4.7 kg/m², respectively. Higher mean NWI was associated with greater odds of rHOA (OR 1.22, 95% CI 1.09-1.36; p<0.001), sHOA (OR 1.22, 95% CI 1.06-1.41; p=0.006), and frequent hip pain (OR 1.12, 95% CI 1.04-1.21; p=0.002). Higher eccentricity ratio was associated with rHOA (OR 1.12, 95% CI 1.02-1.22; p=0.017) and frequent hip pain (OR 1.14, 95% CI 1.07-1.21; p<0.001), but not sHOA (OR 1.12, 95% CI 1.00-1.27; p=0.057). Over 4 years, 96/6,224 hips (1.5%) developed incident rHOA, 46/6,224 hips (0.7%) developed incident sHOA, and 809/6,302 hips (12.8%) developed incident frequent hip pain. Baseline popliteal artery wall measurements were not associated with incident rHOA or sHOA; however, higher mean NWI was associated with incident frequent hip pain (OR 1.16, 95% CI 1.05-1.27; p=0.002).

Automated knee MRI-derived popliteal artery wall biomarkers were associated with prevalent rHOA, sHOA, and frequent hip pain, and mean NWI was associated with 4-year incident frequent hip pain. These findings support opportunistic vascular assessment on knee MRI as a potential imaging marker of vascular-metabolic hip OA and pain phenotypes, although short-term associations with incident structural hip OA were not observed.