title: Prospective evidence for a hip etiology in patellofemoral pain.
abstract: OBJECTIVE
  Patellofemoral pain (PFP) is the leading cause of knee pain in runners. Proximal and distal running mechanics have been linked to the development of PFP. However, the lack of prospective studies limits establishing a causal relationship of these mechanics to PFP. The purpose of this study was to prospectively compare running mechanics in a group of female runners who went on to develop PFP compared with healthy controls. It was hypothesized that runners who go on to develop PFP would exhibit greater hip adduction, hip internal rotation, and greater rear foot eversion.
  
  
  METHODS
  Four hundred healthy female runners underwent an instrumented gait analysis and were then tracked for any injuries that they may have developed over a 2-yr period. Fifteen cases of PFP developed, which were confirmed by a medical professional. Their initial running mechanics were compared to an equal number of runners who remained uninjured.
  
  
  RESULTS
  We found that female runners who developed PFP exhibited significantly greater hip adduction (P = 0.007). No statistically significant differences were found for the hip internal rotation angle (P = 0.47) or rear foot eversion (P = 0.1).
  
  
  CONCLUSIONS
  The finding of greater hip adduction in female runners who develop PFP is in agreement with previous cross-sectional studies. These results suggest that runners who develop PFP use a different proximal neuromuscular control strategy than those who remain healthy. Injury prevention and treatment strategies should consider addressing these altered hip mechanics.
authors.affiliation: Division of Physical Therapy, University of Kentucky, Lexington, KY 40536-0200, USA. b.noehren@uky.edu
authors.forename: Brian
authors.initials: B
authors.lastname: Noehren
authors.forename: Joseph
authors.initials: J
authors.lastname: Hamill
authors.forename: Irene
authors.initials: I
authors.lastname: Davis
mesh_terms: D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D005528:Foot / Q000503:physiopathology; D005684:Gait / Q000502:physiology*; D006621:Hip Joint / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D046788:Patellofemoral Pain Syndrome / Q000209:etiology* / Q000503:physiopathology; D011446:Prospective Studies; D016059:Range of Motion, Articular; D012420:Running / Q000502:physiology*; D055815:Young Adult