title: The Catterall classification of Perthes' disease: an assessment of reliability.
abstract: The reliability of the Catterall grouping of Perthes' disease was examined by determining the agreement between pairs of observers using weighted kappa statistics. Anteroposterior and lateral radiographs of 100 hip joints were grouped independently by four experienced observers. There was a low, and in our opinion, unacceptable degree of inter-observer agreement even when Groups 2 and 3 were combined.
mesh_terms: D006621:Hip Joint / Q000000981:diagnostic imaging*; D006801:Humans; D010007:Osteochondritis / Q000145:classification*; D011859:Radiography