The Evaluation Of Stiffness Of Achilles Tendon In Patients With Diabetes By Two-dimensional Shear Wave Elastography

Purpose:To evaluate the Achilles tendon（AT）stiffness in patients with type 2 diabetes mellitus with two-dimensional shear wave elastography（2D-SWE）and to explore the effect of muscle tension on AT stiffness.Methods:1.The research subjects:According to the Guidelines for the Prevention and Treatment of Type 2 Diabetes in China（2017 Edition）and the Consensus on Diagnosis and Treatment of Diabetic Peripheral Neuropathy（DPN）（2013 Edition）,A total of 68 inpatients with type 2 diabetes complicated with DPN and 32 inpatients with type 2 diabetes without diabetic peripheral neuropathy（WDPN）diagnosed in the First Affiliated Hospital of Nanchang University from October 2019 to October 2020were collected.They were the DPN group and the WDPN group,respectively.At the same time,32 healthy volunteers with matched age,gender and body mass index（BMI）were selected as the control group.2.The measurement of Achilles tendon:All subjects underwent 2D-SWE examination using the Aixplore type of ultrasonic diagnostic apparatus of the French Super Sonic Imagine and the SL15-4 linear array probe with frequency of 4-15MHz.During the examination,all subjects were in the prone position with their feet hanging naturally outside the examination table to keep their ankles in neutral position.The middle third of the Achilles tendon（2-6cm above the insertion point of calcaneus）is covered with a 1cm thick gel pad.Place the probe lightly on the gel pad without applying any pressure and keep the acoustic beam as perpendicular to the Achilles tendon as possible.After obtaining clear and stable sagittal image of Achilles tendon,then select the foot-ankle mode in the MSK mode of the apparatus for 2D-SWE examination with the area of interest and Q-box measurement area were adjusted to a10×10mm square and a circle with a diameter of 3mm respectively.Bilateral Achilles tendons were measured continuously for 3 times,and the average values were calculated and recorded for statistical analysis.Bilateral Achilles tendons were repeatedly examined at the maximum active plantar flexion and maximum active dorsiflexion of the ankles.Then repeat this procedure at the maximum active plantar flexion and the maximum active dorsiflexion of the ankles.E_pla,E_neuand E_dorwere defined as mean Young’s modulus of AT measured by 2D-SWE in the active maximal plantar flexion,the neutral position and the active maximal dorsiflexion of ankle,respectively.The muscle tension of AT in the three positions increased successively.3.Statistical analysis:Young’s modulus of Achilles tendon among and within each group was compared and analyzed.p<0.05 was considered statistically significant.Results:1.A total of 200 tendons from 100 patients with type 2 diabetes and 64 tendons from 32 healthy volunteers were included.Among them,there were 68 patients in DPN group including 39 males and 29 females.WDPN group included 32 patients including 16 males and 16 females.The control group had 32 cases including 12males and 20 females.There were no significant differences in subjects’gender,average age,BMI and Hb A1c among all groups（p>0.05）.The median duration of disease in the DPN group and the WDPN group was 10.0 years and 2.8 years,respectively,and the difference was statistically significant（p<0.05）.2.There was no significant difference in Young’s modulus between left and right Achilles tendon among all groups in all three positions of ankle joint:neutral position,maximum active plantar flexion and maximum active dorsiflexion of the ankles.（p>0.05）.3.By comparing Young’s modulus of Achilles tendon among all groups,E_neuincreased successively among DNP group,WDPN group and control group,and the differences were statistically significant（p<0.05）.There were no significant differences in either E_plaor E_dorbetween DPN group and non-DPN group（p>0.05）,but E_plaand E_dorwere significantly lower in these two groups than those in control group（p<0.05）.4.By comparing Young’s modulus of Achilles tendon within all groups,there were significant differences among E_pla、E_neuand E_dorwithin every group,except for between E_plaand E_neuin non-DPN group（p>0.05）,and the variables listed in increasing order are as follows:E_pla、E_neuand E_dor.5.The results of correlation analysis showed that the course of disease,Hb A1c were weakly correlated with E_dorin DPN group（r=-0.255,-0.352,p<0.05）.In WDPN group,gender was correlated with E_plaand E_dor（r=0.428,0.546,p<0.05）,and the values of E_plaand E_dorin female patients were higher than those in male patients.Conclusion:1.Compared with the control group,the Achilles tendon was softer in diabetic patients.The softening of Achilles tendon may be a new and early ultrasonic sign of diabetic foot and reveal the patients with a risk of diabetic foot.2.Compared with patients in the WDPN group,the Achilles tendon was softer in the DPN group,suggesting that DPN may exacerbate the softening of the Achilles tendon in diabetic patients.Therefore,the quantitative assessment of the stiffness of the Achilles tendon by 2D-SWE may provide new evidence for the early diagnosis of DPN,especially for those DPN patients without obvious clinical symptoms,which enable early intervention.3.Muscle tension has a decisive effect on the stiffness of the Achilles tendon,and the Angle of the ankle joint should be strictly controlled to accurately measure.