Ultrasonography of Knee Muscles During SLR With Different Positions of Hip and Ankle in Patellofemoral Pain Syndrome

Abstract

Objective Due to the substantial prevalence of patellofemoral pain syndrome and the importance of quadriceps strengthening in knee rehabilitation, determining the best way to activate and strengthen the patella stabilizing muscles is considered as one of important keys of treatment. The aim of this study is to evaluate the effect of different hip rotations associated with ankle dorsiflexion during maximal straight leg raising (SLR) maneuver in the sitting position on thickness and fibers angle of vastus medialis oblique (VMO) and vastus lateralis (VL) muscles using ultrasonography. Materials & Methods This quasi-experimental study was performed on 40 individuals (healthy group: 20, patellofemoral pain syndrome [PFPS] group: 20). VMO and VL thickness and fiber angle were measured using ultrasonography during maximal SLR in 6 positions: hip internal, hip external, and neutral rotations with and without ankle dorsiflexion. Results In between-group comparison, no significant difference was found for all variables with different SLR maneuvers (P>0.05). In the within-group comparison, hip external rotation compared to other hip positions without ankle dorsiflexion resulted in a significant increase in VMO thickness and fiber angle in both groups (P<0.05). Also, adding ankle dorsiflexion to different hip rotations during SLR significantly increased the thickness and fiber angle of VMO and VL. Conclusion By changing hip rotations with or without ankle dorsiflexion during SLR, the trend of changes in VMO and VL thickness and fiber angle in the two groups followed the same pattern. Moreover, performing SLR in hip external rotation with ankle dorsiflexion can be recommendable for the rehabilitation of PFPS.