[1] Univ Verona, Fac Med & Surg, I-37134 Verona, Italy
[2] Amgen Inc, Thousand Oaks, CA 91320 USA
[3] Univ Louvain, Dept Expt Med, Bone Res Unit, B-3000 Louvain, Belgium
[4] Calif Pacific Med Ctr, Res Inst, San Francisco Coordinating Ctr, San Francisco, CA 94107 USA
[5] Univ Calif San Francisco, San Francisco, CA 94107 USA
[6] Columbia Univ, Med Ctr, Dept Med, New York, NY 10032 USA
[7] Hosp Special Surg, Dept Orthoped Surg, New York, NY 10021 USA