Posts tagged knee stability
Association Between Ankle Mobility and Knee Alignment

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.


The Importance of Ankle Mobility for Proper Knee Mechanics
ankle mobility-stretching-knee-pain-injury

In a previous post, we detailed the latest research on the importance of ankle mobility on knee mechanics.  During weight bearing the shin, tibia, must be able to move forward over the fixed ankle and foot.  Without adequate ankle flexibility and shin moved over the foot to the inside placing the knee at risk of traumatic and overuse injuries.  Conversely, patients with adequate ankle mobility and better able to keep their knee over their foot during a step down test.  Granted, many of these patients may also have hip weakness, but the importance of ankle mobility should not be overlooked.  New research supports the influence of ankle mobility on knee mechanics and stability.

In the Journal of Orthopedic and Sports Physical Therapy authors examined 30 healthy participants as they underwent biomechanical testing in a laboratory (Rabin et al. 2016).  The participants were tested on a step down test and then underwent testing of ankle mobility.  Authors then split the group in two based on either low or high degrees of mobility.  As expected, the group with the least amount of ankle mobility demonstrated less knee stability and more knee movement than the group with better ankle mobility.  Athletes and patients are encouraged to assess and treat limited ankle mobility for improvement in knee stability.