The ankle plays a critical role in the ability of the knee to stay over the foot during functional tasks such as walking, running, and stair climbing.  Under normal conditions the mobility of the ankle allows the leg to move forward over the weight bearing foot.  If this range of motion is limited, the leg moves inward causing the knee to move inside of the weight bearing foot.  This position, known as knee valgus, is a common cause of IT band pain, knee pain, patellofemoral pain, and acute ligamentous and meniscal injuries to the knee.  In our Boulder Physical Therapy practice we find many individuals with knee pain who lack adequate ankle mobility.  A recent review article analyzed the available literature associating this mobility with proximal knee stability.

Lima and colleagues reviewed the available literature on the association between ankle mobility, dorsiflexion, and knee position (Physical Therapy in Sport. 2017).  The authors pooled the results of 17 studies and found an association between ankle mobility and dynamic knee alignment.  In addition, they found measurements of the ankle in weight bearing and non weight bearing were both significant for dynamic knee valgus.  This study lends further support to the importance of examining and treating ankle impairments in patients with knee pain.