Hip Strength Is Greater in Athletes Who Subsequently Develop Patellofemoral Pain.
BACKGROUND
Hip and knee strength abnormalities have been implicated in patellofemoral pain (PFP) in multiple studies. However, the relationship is unclear, as many of these studies have been retrospective.


OBJECTIVE
To compare prospective hip and knee isokinetic strength in young female athletes who subsequently went on to develop PFP relative to their uninjured, healthy peers.


METHODS
Descriptive epidemiology study.


METHODS
Adolescent female athletes (N = 329) were tested for isokinetic strength of the knee (flexion and extension) and hip (abduction) and screened for the prevalence of PFP before their basketball seasons. After exclusion based on current PFP symptoms, 255 participants were prospectively enrolled in the study. A 1-way analysis of variance was used to determine between-group differences in incident PFP and the referent (no incident PFP) participants.


RESULTS
The cumulative incidence rate for the development of PFP was 0.97 per 1000 athlete-exposures. Female athletes who developed PFP demonstrated increased normalized hip abduction strength (normalized torque, 0.013 ± 0.003) relative to the referent control group (normalized torque, 0.011 ± 0.003) (P < .05). Unlike hip strength, normalized knee extension and knee flexion strength were not different between the 2 groups (P > .05).


CONCLUSIONS
The findings in this study indicate that young female athletes with greater hip abduction strength may be at an increased risk for the development of PFP. Previous studies that have looked at biomechanics indicated that those with PFP have greater hip adduction dynamic mechanics.


CONCLUSIONS
Combining the study data with previous literature, we theorize that greater hip abduction strength may be a resultant symptom of increased eccentric loading of the hip abductors associated with increased dynamic valgus biomechanics, demonstrated to underlie increased PFP incidence. Further research is needed to verify the proposed mechanistic link to the incidence of PFP.
Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Wellington Orthopaedic and Sports Medicine, Cincinnati, Ohio, USA Mercy Hospital Anderson/University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.
Kristen A
KA
Herbst
Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Division of Health Sciences, Department of Athletic Training, College of Mount St Joseph, Cincinnati, Ohio, USA.
Kim D
KD
Barber Foss
Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.
Lauren
L
Fader
Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Departments of Pediatrics and Orthopaedic Surgery, University of Cincinnati, Cincinnati, Ohio, USA The Sports Health and Performance Institute, OSU Sports Medicine, Departments of Physiology & Cell Biology, Orthopaedic Surgery, Family Medicine, Rehabilitation Sciences, and Biomedical Engineering, Ohio State University Medical Center, Columbus, Ohio, USA.
Timothy E
TE
Hewett
Rehabilitation Sciences and Physiotherapy, Ghent University, Ghent, Belgium Rehabilitation Department, Aspetar Orthopedic and Sports Medicine Hospital, Doha, Qatar.
Erik
E
Witvrouw
Wellington Orthopaedic and Sports Medicine, Cincinnati, Ohio, USA.
Denver
D
Stanfield
Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Wellington Orthopaedic and Sports Medicine, Cincinnati, Ohio, USA Departments of Pediatrics and Orthopaedic Surgery, University of Cincinnati, Cincinnati, Ohio, USA The Sports Health and Performance Institute, OSU Sports Medicine, Departments of Physiology & Cell Biology, Orthopaedic Surgery, Family Medicine, Rehabilitation Sciences, and Biomedical Engineering, Ohio State University Medical Center, Columbus, Ohio, USA The Micheli Center for Sports Injury Prevention, Waltham, Massachusetts, USA greg.myer@cchmc.org.
Gregory D
GD
Myer
D000293:Adolescent; D056352:Athletes; D001490:Basketball; D002648:Child; D005260:Female; D006801:Humans; D015994:Incidence; D007717:Knee / Q000473:pathology*; D007719:Knee Joint / Q000473:pathology*; D046788:Patellofemoral Pain Syndrome / Q000209:etiology*; D011446:Prospective Studies; D016059:Range of Motion, Articular; D019415:Torque
anterior knee pain; female athlete; hip strength; patellofemoral pain