title: Analysis of failed surgery for patellar instability in children with open growth plates.
abstract: OBJECTIVE
  Many surgical procedures have been proposed to treat recurrent patellar dislocation in children. In recent years, a more tailored approach considering the underlying pathology has been advocated. The aim of the study was to analyze a group of patients with recurrent patellofemoral instability after unsuccessful operative stabilization (Roux-Goldthwait procedure, lateral release, medial reefing or in combination) in childhood and adolescence.
  
  
  METHODS
  A total of 37 children and adolescents with recurrent patellofemoral instability despite previous surgery were analyzed retrospectively. Radiographic examination included AP and lateral views to assess patella alta and limb alignment. MRI was performed to evaluate trochlear dysplasia and tibial tubercle-trochlear groove (TTTG) distance. As a control group, 23 age- and sex-matched adolescents that were treated with a favorable outcome after medial reefing alone or combined with a Roux-Goldthwait procedure were analyzed.
  
  
  RESULTS
  Severe trochlear dysplasia (type B-D according to Dejour) as detected on MRI scans was found significantly more often in the study group (89%) than in the control group (21%). No statistical difference of patellar height ratio (Insall-Salvati index) and TTTG distance between the two groups could be found.
  
  
  CONCLUSIONS
  Of the measured parameters, only the incidence of trochlear dysplasia was increased. Trochlear dysplasia therefore seems to be a major risk factor for failure of operative stabilization of recurrent patellofemoral instability in children and adolescents. The results in children are in consensus with the literature in adults that a more tailored operative therapy including reconstruction of the MPFL and trochleaplasty has to be considered.
  
  
  METHODS
  Retrospective study, Level III.
authors: University of Ulm, Ulm, Germany. manfred.nelitz@rku.de
authors: Manfred
authors: M
authors: Nelitz
authors: Michael
authors: M
authors: Theile
authors: Daniel
authors: D
authors: Dornacher
authors: Julia
authors: J
authors: Wölfle
authors: Heiko
authors: H
authors: Reichel
authors: Sabine
authors: S
authors: Lippacher
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006132:Growth Plate / Q000000981:diagnostic imaging; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D031222:Patellar Dislocation / Q000000981:diagnostic imaging / Q000601:surgery*; D017847:Patellar Ligament / Q000293:injuries* / Q000601:surgery; D057071:Patellofemoral Joint / Q000000981:diagnostic imaging / Q000293:injuries* / Q000601:surgery; D011183:Postoperative Complications; D011859:Radiography; D012008:Recurrence; D012189:Retrospective Studies; D017211:Treatment Failure; D016896:Treatment Outcome; D055815:Young Adult