[1] ISICO Italian Sci Spine Inst, Via Roberto Bellarmino 13-1, I-20141 Milan, Italy
[2] HFR Fribourg Hop Cantonal, Dept Rheumatol, Fribourg, Switzerland
[3] Western Univ, Fac Hlth Sci & Westerns Bone & Joint Inst, London, ON, Canada
[4] Univ Oulu, Oulu Univ Hosp, Med Res Ctr, Oulu, Finland
[5] Rehabil Unit South Karelia Social & Hlth Care Dis, Oulu, Finland
[6] La Statale Univ, Dept Biomed Surg & Dent Sci, Milan, Italy
[7] IRCCS Galeazzi Orthoped Inst, Milan, Italy