ROLE OF SHEAR WAVE ELASTOGRAPHY IN ASSESSING ACHILLES TENDON IN NORMAL INDIVIDUALS, DIABETIC PATIENTS WITH AND WITHOUT FOOT COMPLICATIONS

Abstract

Introduction: Diabetes mellitus (DM) is an endocrine disorder which is characterized by several metabolic abnormalities as well as long-term complications. Among the dreaded consequences of diabetes mellitus (DM) is diabetic foot. According to a number of studies, diabetic patients may experience foot issues as a result of alterations in the Achilles tendon (AT). In diabetic patients, early detection of these changes may prevent impending foot complications. Aim:  To perform ultrasound and document the thickness of the Achilles tendon in normal individuals, diabetic patients with and without foot complications.  To assess the role of shear wave elastography in assessing Achilles tendon stiffness and deriving cut-off values in normal individuals, diabetic patients with and without foot complications. Methods: Shear wave elastography (SWE) was used to assess the elasticity of AT in 55 healthy volunteers, 55 patients with type 2 DM (T2DM) without foot complications and 55 patients with type 2 DM with foot complications. The thickest part of the middle portion of the Achilles tendon, which is nearly 2-6 cm proximal to the calcaneus insertion, was chosen for shear wave elastographic examinations & thickness calculation. Results: The study found a male predominance with 121 (73.3%) males and 44 (26.7% females) patients. The mean age was 55.14±10.11, with no significant differences in age or disease conditions. Diabetic patients had significantly higher fasting blood sugar (FBS) levels and post-prandial blood sugar (PPBS) levels compared to healthy individuals. The AT thickness was more in diabetic patients with foot complications compared to non-diabetic controls and diabetic patients without foot complications. The cutoff value for AT thickness xvi for healthy vs T2DM without foot complications was 7.55mm, with 96.4% sensitivity and 79.4% specificity. The cutoff value for AT thickness for T2DM without vs with foot complications was 8.95mm, with 81.8% sensitivity and 78.18% specificity. The Young's modulus was significantly lower in diabetic patients with foot complications as compared to the other two groups, which implies that the elasticity of AT in patients with foot complications was significantly lower as compared to those diabetic patients without foot complications. A cut-off value of 120 kPa had a very good diagnostic accuracy (AUC = 0.879) to differentiate between the AT stiffness of diabetic patients with foot complications and diabetic patients without foot complications with a specificity of 78.18% and sensitivity of 81.5 %.. Conclusion: Modifications in the structure of AT occurs before the onset of foot complications in diabetic patients. Reduced elasticity & thickening of AT is a reliable marker of impending foot complications in diabetic patients