title: Evaluation of conventional selection criteria for psoas lengthening for individuals with cerebral palsy: a retrospective, case-controlled study.
abstract: BACKGROUND
  Psoas lengthening surgery has been advocated to improve hip function in patients with spastic cerebral palsy (CP); however, no uniform or standardized selection criteria have been agreed upon. Our study evaluated a proposed algorithm for selecting patients for psoas surgery to be included as part of a single-event multilevel surgery (SEMLS).
  
  
  METHODS
  A retrospective, case-controlled study was performed on children with CP who underwent a SEMLS and met 2 of 3 of the following proposed selection criteria after gait analysis: (1) maximum hip extension no > 8 degrees of flexion, (2) maximum pelvic tilt > 24 degrees, and (3) pelvic tilt range of motion > 8 degrees. One group had a psoas lengthening surgery as part of their SEMLS (psoas group) and 1 group did not (control group). Among other variables, overall kinematic gait pathology, as measured by the Gait Deviation Index (GDI), Pelvis and Hip kinematic gait pathology, as measured by the Pelvis and Hip Deviation Index (PHiDI), and Gross Motor Function Classification System (GMFCS) levels were compared.
  
  
  RESULTS
  Eighty-seven sides met 2 of 3 of the proposed selection criteria; 32 in the psoas group and 55 in the control group. Both groups showed improvement in function after SEMLS. There was a significantly greater improvement in GDI for the psoas group in patients with GMFCS levels 3 and 4 (+12.9 vs. +7.7, P = 0.02). Odds ratio for "poor outcomes" in PHiDI for the control group compared with the psoas group was 5.1 (95% CI, 1.37-18.95), which was significant.
  
  
  CONCLUSIONS
  Certain patients that met the proposed selection criteria did functionally better if psoas surgery was included as part of their SEMLS, specifically those that were classified as GMFCS levels 3 and 4. The risk of no improvement in hip function after SEMLS was greater if the parameters were met and psoas lengthening was not performed. The differences between the groups were modest by clinical standards, leaving open the possibility that other selection criteria may better differentiate those that would do well and those that would do poorly after psoas surgery.
  
  
  METHODS
  Retrospective, case-controlled study. Level III.
authors.affiliation: Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, USA.
authors.forename: Walter H
authors.initials: WH
authors.lastname: Truong
authors.forename: Adam
authors.initials: A
authors.lastname: Rozumalski
authors.forename: Tom F
authors.initials: TF
authors.lastname: Novacheck
authors.forename: Cammie
authors.initials: C
authors.lastname: Beattie
authors.forename: Michael H
authors.initials: MH
authors.lastname: Schwartz
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002547:Cerebral Palsy / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005684:Gait / Q000502:physiology*; D006615:Hip / Q000503:physiopathology*; D006801:Humans; D008297:Male; D019637:Orthopedic Procedures / Q000379:methods*; D018579:Patient Selection; D016658:Psoas Muscles / Q000503:physiopathology / Q000601:surgery*; D020127:Recovery of Function; D012189:Retrospective Studies; D016896:Treatment Outcome