Background/Purpose: Ehlers-Danlos syndrome is a group of inherited disorders that affects connective tissues primarily skin, joints and blood vessel walls. Ehlers-Danlos syndromes usually have overly flexible joints and stretchy, fragile skin. The purpose of this research is to measure the Stiffness index(T Score and Z score) by Achilles express. Achilles express Ultrasonometry provides a measurement of physical properties of bone. Two of the most commonly used ultrasound measures are Speed Of Sound (SOS, in m/sec) and Frequency Attenuation (Broadband Ultrasound Attenuation; BUA in dB/MH2) of a sound wave as it travels through bone.

Methods: 38 EDS patients and 23 non EDS controls are randomly selected from our clinic and Stiffness index is calculated by Achilles express. To express the ultrasound results, the Achilles combines the SOS and BUA values to calculate a clinical measure called the Stiffness Index (SI).Measurement of SOS in the heel involves accurate determination of the transit time of a sound wave as it passes through the heel. This is compared to the time required for a signal to pass through the water bath alone. Stiffness Index combines BUA and SOS into single clinical measure that has a lower precision error than either variable alone. SI= [ 0.67*BUA + 0.28*SOS ] – 420.T score higher than -1.0 indicates low risk,score between -1.0 and -2.5 indicates intermediate risk,score lower than -2.5 indicates high risk.ANOVA analysis is performed

Results: Out of 61 subjects, 98% are females (n=60, age 31.49±11.53) , 2% are males (n=2, age 17),Mean age of 38 EDS patients (31.31±11.10) ,Mean age of 23 non EDS controls (30.79±11.02) , ANOVA:Stiffness index (Mean ± Standard deviation) in 38 EDS patients 92.73±16.65, In 23 non EDS controls 103.43±15.50 (Stiffness index EDS vs non EDS, P=0.01), T Score EDS vs Non EDS controls (-0.5±1.09 Vs 0.23±0.96 ,P =0.01), Z score EDS vs Non EDS controls (-0.3±1.12 Vs 0.33±0.86 ,P =0.02).

Conclusion: Patients with EDS appear to have low stiffness index at a young age. They may be predisposed to osteopenia or osteoporosis. Further research is needed to develop a proper strategy to avoid future complications.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/stiffness-index-study-in-ehler-danlos-syndrome/