title: Hip flexion deformity improves without psoas-lengthening after surgical correction of fixed knee flexion deformity in spastic diplegia.
abstract: BACKGROUND
  It is unclear if psoas lengthening surgery is required in the treatment of patients with cerebral palsy (CP) with hip flexion deformity and previous studies show equivocal results with regard to functional outcome.
  
  
  METHODS
  This study retrospectively assessed 12 patients with a diagnosis of spastic diplegia who underwent single event multilevel surgery in order to correct deformities in the sagittal plane distal to the hip. Both clinical and instrument gait analysis results were recorded preoperatively, at one year (short term) and at five years (mid term) postoperatively.
  
  
  RESULTS
  Clinically measured hip and knee movement improved at both short and mid term follow up. Correlations of clinically measured maximum hip and knee extension were significant at all three time points. Angles at terminal stance/toe off for hip and knee from kinematic data also showed significant correlations at all three time points.
  
  
  CONCLUSIONS
  Our study demonstrates that the hip flexion deformities encountered in these patients will improve spontaneously when the distal fixed knee flexion deformity is surgically corrected. Therefore correction at the knee allows the ground reaction force to assume a more normal position resulting in correction at the hip over time. This then removes the need for surgery at the hip level. This fact is especially important when applied to psoas lengthening as this procedure can cause significant reduction in propulsion power.
authors.affiliation: Paediatric Orthopaedic Department, University Children's Hospital Basle, Basle, Switzerland. erich_rutz@hotmail.com
authors.forename: Erich
authors.initials: E
authors.lastname: Rutz
authors.forename: Mark S
authors.initials: MS
authors.lastname: Gaston
authors.forename: Oren
authors.initials: O
authors.lastname: Tirosh
authors.forename: Reinald
authors.initials: R
authors.lastname: Brunner
mesh_terms: D000293:Adolescent; D002547:Cerebral Palsy / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D002648:Child; D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D006621:Hip Joint / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007719:Knee Joint / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D016658:Psoas Muscles / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D016138:Walking