title: Anterior knee pain in patients with cerebral palsy.
abstract: BACKGROUND
  The aim of this study was to identify the risk factors for anterior knee pain in patients with cerebral palsy.
  
  
  METHODS
  This prospective study investigated the risk factors for anterior knee pain in 127 ambulatory patients with spastic cerebral palsy in terms of walking pain, resting pain, and provocative pain. Demographic data analysis and physical examination for measuring the knee flexion contracture and unilateral and bilateral popliteal angles were performed. Patellar height was measured on radiographs, and patella alta was identified. The risk factors for anterior knee pain were analyzed using multivariate analysis with a generalized estimating equation.
  
  
  RESULTS
  Seventy-seven patients were found to have patella alta based on the radiographic measurements (60.6%). Overall, sixteen patients (12.6%) had either unilateral or bilateral anterior knee pain. Of these, 6 patients showed a visual analogue scale (VAS) ≤ 3, 9 patients showed 3 < VAS ≤ 7, and one patient showed a VAS > 7. Age was found to be a significant risk factor for walking pain and resting pain with odds ratios (ORs) of 1.08 (95% confidence interval [CI], 1.02 to 1.14) and 1.09 (95% CI, 1.03 to 1.15), respectively. In the multivariate analysis, knee flexion contracture was a significant protective factor with an OR of 0.92 (95% CI, 0.85 to 0.98).
  
  
  CONCLUSIONS
  Approximately 12.6% of ambulatory patients with spastic cerebral palsy were found to have anterior knee pain in our hospital-based cohort study. Age was found to be a significant risk factor for anterior knee pain while walking and resting.
authors.affiliation: Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Young
authors.initials: Y
authors.lastname: Choi
authors.affiliation: Department of Orthopedic Surgery, Dongguk University Ilsan Hospital, Dongguk University College of Medicine, Goyang, Korea.
authors.forename: Sang Hyeong
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Chin Youb
authors.initials: CY
authors.lastname: Chung
authors.affiliation: Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Moon Seok
authors.initials: MS
authors.lastname: Park
authors.affiliation: Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Kyoung Min
authors.initials: KM
authors.lastname: Lee
authors.affiliation: Department of Orthopedic Surgery, Myongji Hospital, Goyang, Korea.
authors.forename: Ki Hyuk
authors.initials: KH
authors.lastname: Sung
authors.affiliation: Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Sung Hun
authors.initials: SH
authors.lastname: Won
authors.affiliation: Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: In Hyeok
authors.initials: IH
authors.lastname: Lee
authors.affiliation: Department of Orthopedic Surgery, Seoul National University Children's Hospital, Seoul, Korea.
authors.forename: In Ho
authors.initials: IH
authors.lastname: Choi
authors.affiliation: Department of Orthopedic Surgery, Seoul National University Children's Hospital, Seoul, Korea.
authors.forename: Tae-Joon
authors.initials: TJ
authors.lastname: Cho
authors.affiliation: Department of Orthopedic Surgery, Seoul National University Children's Hospital, Seoul, Korea.
authors.forename: Won Joon
authors.initials: WJ
authors.lastname: Yoo
authors.affiliation: Department of Orthopedic Surgery, Ewha Womans University Mokdong Hospital, Seoul, Korea.
authors.forename: Seung Yeol
authors.initials: SY
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000367:Age Factors; D018771:Arthralgia / Q000209:etiology* / Q000503:physiopathology; D002547:Cerebral Palsy / Q000150:complications* / Q000503:physiopathology; D002648:Child; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D008297:Male; D011446:Prospective Studies; D016059:Range of Motion, Articular; D012307:Risk Factors; D016138:Walking; D055815:Young Adult
keywords: Cerebral palsy; Patella alta; Patellofemoral pain syndrome; Popliteal angle