RESUMEN
OBJECTIVE: The sagging rope sign is a radio-opaque line, seen on radiographs of the 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. DESIGN: Serial radiograms, along with 2-dimensional and 3-dimensional CT images were studied in 42 achondroplastic patients. PATIENTS: Forty-two achondroplastic patients, reported at our institute (for routine outpatient consultation, spine surgeries, deformity corrections, limb-lengthening procedures) were included in this study. There were 26 males and 16 females. RESULTS: The sign was observed bilaterally, in all patients. Evaluation of CT images revealed spherical heads, with presence of circumferential overhang in all hips. This circumferential overhang, seen on 3-D CT scan, corresponded to the sagging rope sign on radiographs. CONCLUSIONS: 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 Perthes' disease, and its presence does not carry a bad prognosis in achondroplasia.
Asunto(s)
Acondroplasia/diagnóstico , Enfermedad de Legg-Calve-Perthes/diagnóstico , Acondroplasia/diagnóstico por imagen , Acondroplasia/patología , Adolescente , Adulto , Niño , Preescolar , Diagnóstico Diferencial , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Cadera/diagnóstico por imagen , Cadera/patología , Humanos , Enfermedad de Legg-Calve-Perthes/diagnóstico por imagen , Enfermedad de Legg-Calve-Perthes/patología , Masculino , Tomografía Computarizada por Rayos XRESUMEN
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.
