Descending stairs: Good or bad task to discriminate women with patellofemoral pain?

BACKGROUND: There is no consensus on kinematics alterations during descending stairs in females with patellofemoral pain (PFP). In addition, there are no studies that have evaluated the three dimensional kinematics of the trunk, pelvis, hip, knee, and ankle using a multi-segmental model of the foot simultaneously during this task in patients with PFP and evaluated the subphases of stair descent. The objectives of this study were to compare the three dimensional kinematics of the trunk, pelvis, and lower limbs during different subphases of stair descent and identify the discriminatory capacity of the kinematic variables among women with PFP and healthy women. METHODS: In this cross-sectional study, thirty-four women with PFP and thirty-four pain free women between 18 and 35 years-old were submitted to three-dimensional kinematic evaluation during stair descent. RESULTS: It was observed that kinematic differences between the groups occurred in the first double support phase of the stair descent, with the variables of internal rotation of the hindfoot in relation to the tibia in the initial contact (2.1°; sensitivity = 68.6%, specificity = 61.8%) and contralateral pelvic drop in load response (1.3°, sensitivity = 65.7%, specificity = 63.7%) presenting the best ability to discriminate women with and without PFP. CONCLUSION: Our results suggest that kinematic changes during stair descent should be used with caution during the evaluation and decision-making process in women with PFP.