Single-Leg Squat Test in the Clinical Setting Does Not Discriminate Patients With Femoroacetabular Impingement Syndrome From Asymptomatic Individuals

Context: Laboratorial 3-dimensional kinematic analyses have shown changes in the single-leg squat's (SLS) pattern of patients with femoroacetabular impingement syndrome (FAIS). However, it is unknown whether clinicians are able to detect these changes using 2-dimensional kinematics. Objective: To compare the frontal plane 2-dimensional kinematics of patients with FAIS and asymptomatic individuals in the SLS test performed in a clinical setting. Design: Case-control study. Setting: Physical therapy clinic. Participants: Twenty men with bilateral FAIS and 20 asymptomatic men. Main Outcome Measures: Two-dimensional kinematic analysis was collected in the frontal plane during the execution of the SLS test. The outcomes were squat depth, pelvic drop (pelvis angle relative to the horizontal plane), hip adduction (femur angle relative to the pelvis), and knee valgus (femur angle relative to the tibia). Results: Most and least painful limbs of patients with FAIS had squat depth (9.8% [2.9% ] and 9.5% [3.1% ] of height), pelvic drop (4.2 degrees [3.9 degrees] and 3.7 degrees [4. 2 degrees]), hip adduction (74.9 degrees [5.8 degrees] and 75.9 degrees [5.7 degrees]), and knee valgus (4.0 degrees [11. 0 degrees] and 5.0 degrees [9.9 degrees]) similar to asymptomatic individuals (9.0% [2.3%], 4.8 degrees [2.6 degrees], 73.7 degrees [4.9 degrees], and -1.7 degrees [8.5 degrees]; P> .05 for all). Conclusion: The frontal plane 2-dimensional kinematic analysis of the SLS test in the clinical setting is not able to distinguish patients with FAIS from asymptomatic individuals.