Is there any relationship between Q-angle and lower extremity malalignment?

The aim of this study was to assess the relationship between Q-angle and lower extremity alignment in women with unilateral patellofemoral pain syndrome (PFPS).

Eighty-five women with unilateral patellofemoral pain participated in the study, with each subject acting as their own internal control using the unaffected limb. Lower extremity alignment and Q-angles of the affected and unaffected knees were compared.

There was a significant difference in the Q-angle between the affected (19.61±4.35) and the unaffected (17.63±4.29) side (p=0.00). There was also a significant difference in the lateral distal femoral angle (LDFA) (81.00±2.58 vs. 81.83±3.03; p=0.03) and no significant difference in the medial proximal tibial angle (MPTA) (87.88±2.63 vs. 87.60±3.29; p=0.51) between the affected and the unaffected side. There was no relationship between the Q-angle and LDFA (r=0.001, p=0.99), and MPTA (r=-0.051, p=0.64) in the affected side of the patients. There was also no relationship between the Q-angle and LDFA (r=0.179, p=0.64), and MPTA (r=-0.146, p=0.18) in the unaffected side of the patients.

Increased Q-angle and decreased LDFA may be associated with PFPS although cause or effect cannot be established. There was no relationship between the Q-angle and lower extremity malalignment. Large prospective longitudinal studies are needed to detect changes in the femoral anteversion and toe-in gait and to establish if these features are a cause of PFPS.