Evaluation of achilles tendon elasticity using shear wave elastography in patient with chronic kidney disease with and without Diabetes mellitus

Evaluation of Achilles Tendon Elasticity Using Shear Wave Elastography in Patient with Chronic Kidney Disease with and without Diabetes Mellitus Introduction and Objective The Achilles tendon originates from the tendinous portions of the gastrocnemius and soleus muscles and is the strongest and thickest tendon in the human body. However, it is also the tendon most commonly subject to rupture. The etiology of Achilles tendon rupture varies widely in the literature. Uremic toxins can contribute to tendon degeneration and spontaneous rupture. Moreover, metabolic acidosis, hypoxia, and hyperparathyroidism secondary to Chronic Kidney Disease (CKD), as well as Diabetes Mellitus (DM), which frequently accompanies CKD, may lead to tendon degeneration due to by-products resulting from abnormalities in glucose metabolism. The Achilles tendon can be evaluated using ultrasonography. In recent years, studies have been conducted on the evaluation of the Achilles tendon using Shear Wave Elastography (SWE), a technique integrated into ultrasonography devices that provides information on tissue elasticity. Shear wave elastography (SWE) is a recently developed ultrasonographic technique that estimates tissue stiffness by measuring tissue deformation in response to mechanical shear waves applied in parallel to the tissue structure. The aim of this thesis is to evaluate the Achilles tendons of patients with chronic kidney disease, both with and without coexisting diabetes mellitus, using ultrasonography and shear wave elastography. Materials and Methods This prospectively designed study was approved by the institutional ethics committee. Prior to all procedures, written and verbal informed consent was obtained from all voluntary participants. A total of 105 individuals (54 patients with CKD with or without DM, and 51 healthy controls) were evaluated. Following renal ultrasonography, participants were clinically and sonographically categorized according to the presence of CKD. The CKD group was further divided into two subgroups based on the presence or absence of coexisting DM. After group classification, both Achilles tendons of each participant were assessed using two-dimensional shear wave elastography (2D SWE), and tendon thickness measurements were performed. Differences between the CKD group and the control group were analyzed based on ultrasonographic and elastographic findings. Additionally, statistical analyses were conducted to investigate whether there were significant differences in Achilles tendon parameters between CKD patients with and without diabetes mellitus. Results Of the total participants, 51.4% (54/105) were in the study group and 48.6% (51/105) were in the control group. Among all participants, 44 (41.9%) were female and 61 (58.1%) were male. In the study group, the proportion of females was 44.4% (24/54) and males 55.6% (30/54), whereas in the control group, females comprised 39.2% (20/51) and males 60.8% (31/51). There was no statistically significant difference between the groups in terms of sex distribution (p=0.587). The mean age of the study group was 61.80 ± 14.54 years, while the control group had a mean age of 58.98 ± 12.05 years. The median ages were 63.5 and 58.0 years, respectively. No statistically significant difference was observed between the groups regarding age (p=0.284). In the comparison based on sex, the mean thickness of the right and left Achilles tendons in males was 4.66 ± 0.87 mm and 4.68 ± 0.84 mm, respectively, while in females it was 4.26 ± 0.68 mm and 4.30 ± 0.59 mm, respectively. A statistically significant difference was observed in the mean thickness of the Achilles tendons between sexes on both sides (p=0.009 and p=0.008, respectively). When comparing shear wave elastography values of the right and left Achilles tendons between sexes, the mean values in males were 155.67 ± 49.46 kPa (right) and 154.73 ± 49.90 kPa (left), while in females they were 164.74 ± 54.43 kPa (right) and 172.19 ± 53.64 kPa (left). Although females demonstrated higher mean elastography values than males on both sides, the differences were not statistically significant (p=0.423 and p=0.099, respectively). Among all participants, the mean thickness of the right Achilles tendon was 4.50 ± 0.82 mm with a median of 4.45 mm, while the left Achilles tendon had a mean thickness of 4.52 ± 0.77 mm and a median of 4.42 mm. No statistically significant difference was found between the mean thickness values of the right and left Achilles tendons (p=0.848). The mean shear wave elastography (SWE) value of the right Achilles tendon for all participants was measured as 159.47 ± 51.54 kPa, with a median of 151.05 kPa. For the left Achilles tendon, the mean SWE value was 162.05 ± 51.97 kPa, with a median of 152.02 kPa. No statistically significant difference was found between the mean SWE values of the right and left Achilles tendons (p = 0.694). In the comparison between the study and control groups, the mean right and left Achilles tendon thicknesses were 4.64 ± 0.92 mm and 4.67 ± 0.84 mm, respectively, in the study group, and 4.34 ± 0.68 mm and 4.35 ± 0.64 mm, respectively, in the control group. The mean thicknesses of both right and left Achilles tendons were significantly higher in the study group than in the control group (p = 0.042, p = 0.030). When comparing SWE values between the groups, the study group had mean right and left Achilles tendon values of 187.27 ± 48.58 kPa and 186.75 ± 50.33 kPa, respectively, while the control group had 130.04 ± 36.15 kPa and 135.89 ± 39.71 kPa, respectively. The differences between groups in SWE values for both sides were statistically significant (p<0.001). In the within-group analysis of the study group, the mean thicknesses of the right and left Achilles tendons were 4.64 ± 0.92 mm and 4.67 ± 0.84 mm, respectively. The mean SWE values of the right and left Achilles tendons were 187.27 ± 48.58 kPa and 186.75 ± 50.33 kPa, respectively. No statistically significant differences were found between the right and left sides in terms of either tendon thickness or SWE values (p = 0.848 and p = 0.957, respectively). When Achilles tendon thicknesses were compared according to CKD duration (0-5 years, 5-10 years, and >10 years), the mean ± SD values for the right Achilles tendon were 4.60 ± 1.04 mm, 4.63 ± 0.83 mm, and 4.79 ± 0.69 mm, respectively, with no significant differences observed (p = 0.852). After grading CKD sonographically (Grade 1, Grade 2, Grade 3), the mean right Achilles tendon thicknesses were 4.82 ± 0.84 mm, 4.28 ± 1.07 mm, and 4.74 ± 0.85 mm, respectively. The differences between grades were not statistically significant (p = 0.202). A similar analysis of the left Achilles tendon also showed no significant differences between grades (p = 0.686). For the right Achilles tendon SWE values, the means for Grade 1, 2, and 3 were 174.62 ± 50.34 kPa, 189.85 ± 47.62 kPa, and 200.74 ± 47.17 kPa, respectively; the differences were not statistically significant (p = 0.258). However, the mean left Achilles tendon SWE value showed an increasing trend across grades: 165.54 ± 53.20 kPa in Grade 1, 195.72 ± 44.94 kPa in Grade 2, and 205.47 ± 44.36 kPa in Grade 3. Median values also increased accordingly: 168.37, 199.20, and 214.99. This upward trend was found to be statistically significant (p = 0.036), with a notable difference between Grade 1 and Grade 3. In CKD patients with concomitant diabetes mellitus (DM), both right and left Achilles tendon thicknesses were significantly higher compared to non-diabetic patients (p = 0.050 and p = 0.030, respectively). SWE-derived elasticity values were also significantly higher in the diabetic group for both Achilles tendons (right: p < 0.001; left: p < 0.001). When evaluated based on GFR categories (30-120, 15-30, and 0-15 mL/min/1,73 m²), no statistically significant differences were found in Achilles tendon thickness or SWE values for either side (p > 0.05). Conclusion In individuals with chronic kidney disease (CKD), Achilles tendon thickness and stiffness were found to differ from those of healthy individuals, independently of age and sex, and in association with the duration of the disease. The presence of concomitant diabetes mellitus (DM) in CKD patients was associated with a further increase in tendon stiffness and thickness. Routine evaluation of the Achilles tendon using ultrasonography and sonoelastography in patients with CKD, particularly in those with coexisting DM, may be beneficial for the early detection of tendon pathologies. Keywords: Achilles Tendon, Ultrasonography, Shear Wave Elastography, Chronic Kidney Disease, Diabetes Mellitus.