title: One Stage Bilateral Total Hip Arthroplasty in Siblings with Larsen Syndrome.
abstract: BACKGROUND
  Larsen syndrome is a rare genetic disorder caused by congenital weakness of the connective tissues. It can present with a variety of musculoskeletal and cardiovascular abnormalities. The current report describes two siblings with Larsen Syndrome who presented with severe bilateral hip arthritis and underwent one stage bilateral total hip arthroplasty (THA). The aim was to report on the clinical features of Larsen Syndrome and their implications for total hip replacement surgery.
  
  
  METHODS
  Two siblings, a 32 year-old female and a 30 year-old male, presented with severe bilateral hip arthritis and a history of Larsen Syndrome. Both patients underwent a detailed, multidisciplinary preoperative medical work up and radiological imaging including computer tomography. All four hips were operated using a cementless primary press-fit cup (Pinnacle, DePuy, Warsaw, IN) and a cementless modular stem system (S-ROM, DePuy, Warsaw, IN) utilizing a posterior approach. Prophylactic cerclages wires were placed proximal to the lesser trochanter before stem preparation and bone grafting of bone cysts in the greater trochanter was performed in all four hips.
  
  
  RESULTS
  After 2 years both patients reported significant improvements of function, pain and quality of life. The Oxford hip score improved from preoperative 21 (range 12-24) points up to 39 (range 38-41) points at 2-year follow up. Radiographic follow-up showed good graft incorporation and no signs of implant loosening.
  
  
  CONCLUSIONS
  The current case report suggests that one stage bilateral THA is a feasible treatment option for young adults with Larsen syndrome and secondary arthritis of the hip.
authors.affiliation: Department of Orthopaedic and Trauma Surgery, University Hospital Heidelberg Schlierbacher Landstrasse 200 A, 69118 Heidelberg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Merle
authors.affiliation: Department of Orthopedics, Vienna General Hospital, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
authors.forename: Wenzel
authors.initials: W
authors.lastname: Waldstein
authors.affiliation: Department of Biomechanics, Hospital for Special Surgery, 541 East 71 Street, New York, NY 10021, USA.
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Lipman
authors.affiliation: Adult Reconstruction and Joint Replacement Division, Hospital for Special Surgery, 535 East 70 Street, New York, NY 10021, USA.
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Kasparek
authors.affiliation: Adult Reconstruction and Joint Replacement Division, Hospital for Special Surgery, 535 East 70 Street, New York, NY 10021, USA.
authors.forename: Friedrich
authors.initials: F
authors.lastname: Boettner
keywords: Computer tomography; Hip; Larsen syndrome; Osteoarthritis; Skeletal malformation total hip arthroplasty