title: Unfavorable hip stress distribution after Legg-Calvé-Perthes syndrome: a 25-year follow-up of 135 hips.
abstract: To study the effect of hip and pelvis geometry on development of the hip after Perthes disease, we determined the resultant hip force and contact hip stress distribution in a population of 135 adult hips of patients who had been treated for Perthes disease in childhood. Contra-lateral hips with no record of disease were taken as the control population. Biomechanical parameters were determined by mathematical models for resultant hip force in one-legged stance and for contact hip stress, which use as an input the geometrical parameters assessed from anteroposterior radiographs. The mathematical model for stress was upgraded to account for the deviation of the femoral head shape from spherical. No differences were found in resultant hip force and in peak contact hip stress between the hips that were in childhood subject to Perthes disease and the control population, but a considerable (148%) and significant (p < 0.001) difference was found in the contact hip stress gradient index, expressing an unfavorable, steep decrease of contact stress at the lateral acetabular rim. This finding indicates an increased risk of early coxarthritis in hips subject to Perthes disease.
authors.affiliation: Department of Orthopaedic Surgery, University Medical Centre Ljubljana, Ljubljana, Slovenia.
authors.forename: Boštjan
authors.initials: B
authors.lastname: Kocjančič
authors.forename: Andrej
authors.initials: A
authors.lastname: Moličnik
authors.forename: Vane
authors.initials: V
authors.lastname: Antolič
authors.forename: Blaž
authors.initials: B
authors.lastname: Mavčič
authors.forename: Veronika
authors.initials: V
authors.lastname: Kralj-Iglič
authors.forename: Rok
authors.initials: R
authors.lastname: Vengust
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000503:physiopathology; D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D005270:Femur Head / Q000000981:diagnostic imaging / Q000503:physiopathology; D005271:Femur Head Necrosis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005500:Follow-Up Studies; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D007873:Legg-Calve-Perthes Disease / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008954:Models, Biological; D011859:Radiography; D013314:Stress, Mechanical; D055815:Young Adult
keywords: Perthes disease; avascular necrosis; hip stress; long term follow-up; microparticles