title: Two-dimensional knee valgus displacement as a predictor of patellofemoral pain in adolescent females.
abstract: Patellofemoral pain (PFP) is a prevalent lower limb musculo-skeletal injury in adolescent females. Female athletes with PFP display increased frontal plane knee joint motion in comparison to control subjects. The current investigation aimed to determine prospectively whether two-dimensional knee valgus displacement during landing could predict the risk of developing PFP. Seventy-six injury-free adolescent female athletes (age = 12.9 ±0.35 years) participated. At baseline participants performed three drop vertical jump trials from a 31-cm box. A standard video camera was used to record frontal plane knee joint kinematics. Over the 24-month follow-up, eight participants developed PFP, as diagnosed by a Chartered Physiotherapist. Knee valgus displacement was significantly increased in those who developed PFP compared to those who did not (mean difference = 7.79°; P = 0.002; partial eta squared = 0.07). Knee valgus displacement ≥10.6° predicted PFP with a sensitivity of 0.75 and specificity of 0.85. The associated positive likelihood ratio was 5. These results have clinical utility suggesting that two-dimensional analysis could be implemented to screen for increased risk of PFP in adolescent female athletes.
authors.affiliation: School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland.
authors.forename: S
authors.initials: S
authors.lastname: Holden
authors.affiliation: School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland.|Institute for Sport and Health, University College Dublin, Dublin, Ireland.
authors.forename: C
authors.initials: C
authors.lastname: Boreham
authors.affiliation: School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland.
authors.forename: C
authors.initials: C
authors.lastname: Doherty
authors.affiliation: School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland.|Institute for Sport and Health, University College Dublin, Dublin, Ireland.
authors.forename: E
authors.initials: E
authors.lastname: Delahunt
mesh_terms: D000293:Adolescent; D056352:Athletes / Q000706:statistics & numerical data*; D001696:Biomechanical Phenomena; D002648:Child; D005260:Female; D056304:Genu Valgum / Q000453:epidemiology* / Q000503:physiopathology; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D016013:Likelihood Functions; D046788:Patellofemoral Pain Syndrome / Q000453:epidemiology* / Q000503:physiopathology; D011446:Prospective Studies; D012307:Risk Factors; D014741:Video Recording
keywords: Adolescent; biomechanics; kinematics; patellofemoral pain; prospective; risk factor