Extent of osteonecrosis on MRI predicts humeral head collapse. - Sakai T; Sugano N; Nishii T; Hananouchi T; Yoshikawa H; Sakai, Takashi; Sugano, Nobuhiko; Nishii, Takashi; Hananouchi, Takehito; Yoshikawa, Hideki (Clinical Orthopaedics & Related Research®, 2008)