title: LCPD: reduced range of motion resulting from extra- and intraarticular impingement.
abstract: BACKGROUND
  Legg-Calvé-Perthes disease (LCPD) often results in a deformity that can be considered as a complex form of femoroacetabular impingement (FAI). Improved preoperative characterization of the FAI problem based on a noninvasive three-dimensional computer analysis may help to plan the appropriate operative treatment.
  
  
  OBJECTIVE
  We asked whether the location of impingement zones, the presence of additional extraarticular impingement, and the resulting ROM differ between hips with LCPD and normal hips or hips with FAI.
  
  
  METHODS
  We used a CT-based virtual dynamic motion analysis based on a motion algorithm to simulate the individual motion for 13 hips with LCPD, 22 hips with FAI, and 27 normal hips. We then determined the motion and impingement pattern of each hip for the anterior (flexion, adduction, internal rotation) and the posterior impingement tests (extension, adduction, external rotation).
  
  
  RESULTS
  The location of impingement zones in hips with LCPD differed compared with the FAI/normal groups. Intra- and extraarticular impingement was more frequent in LCPD (79% and 86%, respectively) compared with normal (15%, 15%) and FAI hips (36%, 14%). Hips with LCPD had decreased amplitude for all hip motions (flexion, extension, abduction, adduction, internal and external rotation) compared with FAI or normal.
  
  
  CONCLUSIONS
  Hips with LCPD show a decreased ROM as a result of a higher prevalence of intra- and extraarticular FAI. Noninvasive assessment of impingement characteristics in hips with LCPD may be helpful in the future for establishment of a surgical plan.
authors.affiliation: Department of Orthopaedic Surgery, Inselspital, University of Bern, Freiburgsstrasse, 3010 Bern, Switzerland. moritz.tannast@insel.ch
authors.forename: Moritz
authors.initials: M
authors.lastname: Tannast
authors.forename: Markus
authors.initials: M
authors.lastname: Hanke
authors.forename: Timo M
authors.initials: TM
authors.lastname: Ecker
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Murphy
authors.forename: Christoph E
authors.initials: CE
authors.lastname: Albers
authors.forename: Marc
authors.initials: M
authors.lastname: Puls
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D005260:Female; D057925:Femoracetabular Impingement / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology / Q000601:surgery; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D007873:Legg-Calve-Perthes Disease / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D013557:Switzerland; D014057:Tomography, X-Ray Computed; D055815:Young Adult