The Hidden Burden of Entheseal Pathology in Lower-Limb Pain: A Real-World Ultrasound Study of 667 Adults

Objective To address the limited recognition of structural causes of lower-limb pain and the lack of real-world data on entheseal pathology, we evaluated ultrasound-detected entheseal and tendinous abnormalities in an unselected outpatient population, highlighting the underuse of musculoskeletal ultrasound (MSK US) in early diagnostic assessment despite the frequent misclassification of these conditions as nonspecific soft-tissue or degenerative disorders. Patients and Methods We conducted a retrospective analysis of 667 consecutive adults undergoing standardized MSK US for lower-limb pain in a general ambulatory orthopedic clinic. Fourteen predefined entheseal and tendinous sites across the hip, knee, and ankle–foot regions were evaluated using Outcome Measures in Rheumatology criteria. Prevalence, anatomical distribution, bilaterality, and clinical predictors were assessed using descriptive statistics and multivariable logistic regression. Results Ultrasound-confirmed enthesopathy or tendinopathy was present in 152 of 667 patients (22.8%). Lesions most frequently involved the gluteus medius tendon and plantar fascia (5.5% each, n=37), followed by the semimembranosus (2.8%, n=19), patellar (2.6%, n=17), and Achilles tendons (4.2%, n=28). Abnormalities were predominantly unilateral (<10% bilateral). Increasing age was the only independent predictor of entheseal pathology (adjusted OR 1.26 per 10-year increase; 95% CI, 1.08-1.47). Sex, body mass index, diabetes, and rheumatologic disease were not relatively associated with pathology. Conclusion Entheseal and tendinous abnormalities are common among symptomatic adults in everyday outpatient practice. Systematic integration of MSK US as a first-line assessment tool could improve diagnostic precision and enable targeted management strategies. These findings provide population-relevant evidence to inform musculoskeletal care pathways and health system decision-making.