Uhthoff, Hans K MD, FRCSC, et al. - Stiffness in primary (idiopathic) frozen shoulders has been attributed to a global fibroplasia of the capsule despite the fact surgical release of the capsule at the rotator interval and of the coracohumeral ligament restores motion in almost all patients...Therefore it seems, in patients with primary frozen shoulder, fibroplasia and contracture are two distinct processes