Sagging rope sign in achondroplasia is different from Perthes disease

Chang Wug Oh, Viraj Uttamrao Shingade, Hae Ryong Song, Seung Woo Suh, Jun Seok Hong, Seok Hyun Lee

Research output: Contribution to journalArticlepeer-review


The "sagging rope" sign is a radiopaque line seen on radiographs of hips with Perthes disease. The main purpose of this study was to determine the incidence, cause, and importance of this sign in achondroplasia and to reveal how it differs from in Perthes disease. Serial radiograms, along with two- and three-dimensional CT images were studied in 42 patients with achondroplasia. The sign was observed bilaterally in all patients. Evaluation of CT images revealed spherical heads with the presence of circumferential overhang in all hips. This circumferential overhang seen on three-dimensional CT images corresponded to the sagging rope sign on plain radiographs. The presence of the sagging rope sign in bilateral hips is a characteristic feature of achondroplasia. It usually appears before epiphyseal closure. Its cause, incidence, and nature differ from in Perthes disease, and its presence does not carry a negative prognosis in achondroplasia.

Original languageEnglish
Pages (from-to)722-724
Number of pages3
JournalJournal of Pediatric Orthopaedics
Issue number6
Publication statusPublished - 2005 Nov


  • Achondroplasia
  • Sagging rope sign

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Orthopedics and Sports Medicine


Dive into the research topics of 'Sagging rope sign in achondroplasia is different from Perthes disease'. Together they form a unique fingerprint.

Cite this