Kinematic analyses during stair descent in young women with patellofemoral pain.
BACKGROUND
Compensatory movement strategies may develop in response to pain to avoid stress on the affected area. Patellofemoral pain is characterised by intermittent periods of pain and the present study addresses whether long-term pain leads to compensatory movement strategies that remain even when the pain is absent.


METHODS
Lower extremity kinematics in three dimensions was studied in stair descent in 17 women with patellofemoral and in 17 matched controls. A two-dimensional geometric model was constructed to normalise kinematic data for subjects with varying anthropometrics when negotiating stairs of fixed proportions.


RESULTS
There were minor differences in movement patterns between groups. Knee joint angular velocity in the stance leg at foot contact was lower and the movement trajectory tended to be jerkier in the patellofemoral group. The two-dimensional model showed greater plantar flexion in the swing leg in preparation for foot placement in the patellofemoral group.


CONCLUSIONS
The results indicate that an altered stair descent strategy in the patellofemoral group may remain also in the absence of pain. The biomechanical interpretation presumes that the strategy is aimed to reduce knee joint loading by less knee joint moment and lower impact force.
Grenholm
Anton
A
Dept. of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, SE-901 87 Umeå, Sweden.
Stensdotter
Ann-Katrin
AK
Häger-Ross
Charlotte
C
D000328:Adult; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005260:Female; D005269:Femur / Q000503:physiopathology; D005684:Gait; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008954:Models, Biological; D010329:Patella / Q000503:physiopathology; D046788:Patellofemoral Pain Syndrome / Q000503:physiopathology* / Q000523:psychology; D011597:Psychomotor Performance; D016059:Range of Motion, Articular; D016138:Walking / Q000523:psychology