The sagging rope sign is a thin sclerotic line that crosses the femoral neck and resembles a hanging or sagging rope that is suspended on both ends. This sign is seen in late stage of Perthes disease on plain radiographs of the hip or pelvis.
This sign is thought to indicate damage to the growth plate with a marked metaphyseal reaction, but the origin is unclear.
Since classically it is considered a specific sign of Perthes disease, the same appearance can be seen in severe epiphysitis after forcible reduction of a congenitally dislocated hip, and certain rare epiphyseal dysplasias.
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- 2. Kim HT, Eisenhauer E, Wenger DR. The "sagging rope sign" in avascular necrosis in children's hip diseases--confirmation by 3D CT studies. (1995) The Iowa orthopaedic journal. 15: 101-11. Pubmed