Usefulness of ultrasound in Sudeck's atrophy of the foot.

Quantitative ultrasound (QUS) of bone has been proposed as an inexpensive and radiation-free device method of assessing skeletal status. QUS has been widely used in the assessment of osteoporosis. Until now only few data are available on the usefulness of QUS in different disorders, such as Sudeck's atrophy. To evaluate the ability of QUS in the diagnosis and monitoring of regional osteoporosis, we investigated 19 patients (12 women and 7 men, age range 30-65 years) with osteoporosis of the foot (Sudeck's atrophy), as evidenced by X-ray study and Technetium-99 bone scan. In all patients we measured speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness of the calcaneus using Lunar Achilles Ultrasound, both in the affected and unaffected foot. Bone mineral density at the lumbar spine, by DXA (Hologic QDR 1000), was also performed. QUS was repeated after 3 and 6 months of treatment with salmon calcitonin (100 IU I.M. every second day). At baseline, SOS, BUA, and stiffness, expressed as T-score, were -1.9, -2.4, and -2.4 in unaffected feet and -2.9, -5.1, and -4.3, respectively, in affected feet. The difference between the unaffected and affected foot was significant for SOS, BUA, and stiffness (P < 0.001). No significant difference was found in QUS parameters in the unaffected foot during the study period. After 3 and 6 months of treatment, SOS increased in the affected foot by 0.2% and 0.3%, BUA increased by 6. 2% and 8.2%, and stiffness by 7.5% and 11.1%, respectively. In conclusion, BUA and stiffness seem to be influenced more than SOS by Sudeck's atrophy; QUS, namely, BUA and stiffness, significantly increase with calcitonin treatment. In conclusion, QUS is a sensitive tool in the diagnosis of Sudeck's atrophy of the foot and is adequate for measuring improvement in bone status following treatment.