Trunk and lower extremity segment kinematics and their relationship to pain following movement instruction during a single-leg squat in females with dynamic knee valgus and patellofemoral pain

Abstract

Objectives: To understand how instructing females with patellofemoral pain to correct dynamic knee valgus affects pelvis, femur, tibia and trunk segment kinematics. To determine if pain reduction in the corrected condition was associated with improved segment kinematics.

Design: Cross-sectional.

Methods: A 3D-motion capture system was used to collect multi-joint kinematics on 20 females with dynamic knee valgus and patellofemoral pain during a single-leg squat in two conditions: usual movement pattern, and corrected dynamic knee valgus. During each condition pain was assessed using a visual analog scale. Pelvis, femur, tibia and trunk kinematics in the frontal and transverse planes were compared between conditions using a paired T-test. Pearson correlation coefficients were generated between visual analog scale score and the kinematic variables in the corrected condition.

Results: In the corrected condition subjects had increased lateral flexion of the pelvis toward the weight-bearing limb (p<0.001), decreased femoral adduction (p=0.001) and internal rotation (p=0.01). A trend toward decreased tibial internal rotation (p=0.057) and increased trunk lateral flexion toward the weight-bearing limb (p=0.055) was also found. Lower pain levels were associated with less femoral internal rotation (p=0.04) and greater trunk lateral flexion toward the weight-bearing limb (p=0.055).

Conclusions: Decreased hip adduction after instruction was comprised of motion at both the pelvis and femur. Decreased pain levels were associated with lower extremity segment kinematics moving in the direction opposite to dynamic knee valgus. These results increase our understanding of correction strategies used by females with patellofemoral pain and provide insight for rehabilitation.

Keywords: Dynamic knee valgus; Frontal plane; Single-leg squat; Transverse plane.

Figure 1

Frontal (Y) and transverse (Z) plane angles at peak knee flexion. Add = adduction, IR = internal rotation, Rot-NWB = frontal and transverse plane rotation of trunk and pelvis to the non-weight bearing limb. Error bars are 1 standard error. *p≤.05, ^§p<.06.