Background: Sonography is a useful technique for the study of the Achilles tendon, and specially in the detection of tendon xantomas. Normal sonographic size is not well established, and is essential in the clinical diagnosis of monogenic familial hypercholesterolemia (FH). Possible relationship between Achilles tendon size and plasma lipid concentrations in normolipidemic population is not known.
Subjects and methods: The antero-posterior Achilles tendon diameter (ATD) was measured with high resolution sonography in 100 healthy subjects, 50 males and 50 females, 20-70 years old, 10 subjects for each decade of age and sex. ATD was correlated with age, gender, body mass index, physical activity and lipid and apolipoprotein B plasma concentrations.
Results: The ATD was significantly higher in males than in females, 5.32 (standard desviation [SD] 0.48) mm versus 4.91 (SD 0.47) mm (p < 0.01). In the multivariate analysis, ATD of males was positively associated with total plasma cholesterol (TC) level (p < 0.01). The ATD in females was positively associated with weight (p < 0.01).
Conclusions: Normal ATD has been defined. Its range is relatively narrow and different in both sexes. Similarities in the histology between vascular and tendinous intersticium probably explain the relationship found between Achilles tendon and TC. Achilles tendon size could be a simple marker of lipid deposition in tissues.