[1] Univ Siena, Dept Med Surg & Neurosci, Rheumatol Unit, Siena, Italy
[2] SIUMB Sch Pisa, Adv Musculoskeletal Ultrasound, Pisa, Italy
[3] SIUMB Sch San Giovanni Rotondo, Adv Musculoskeletal Ultrasound, Foggia, Italy
[4] Univ Postgrad Course, Santa Chiara Univ Hosp, SIUMB Adv Sch Musculoskeletal Ultrasound, Dept Clin & Expt Med, Pisa, Italy
[5] San Pietro Fatebenefratelli Hosp, Rome, Italy
[6] San Luca Hosp, Orthopaed & Traumatol Operating Unit, Lucca, Italy