Adequate ankle dorsiflexion is vital for healthy knee function. In addition, lack of ankle dorsiflexion has been linked to hip and low back pain. Ankle dorsiflexion is the motion involving your toes coming up toward the shin (depicted below). Limited ankle dorsiflexion is common following multiple ankle sprains, surgery, tight calf musculature.
Pain can be deceiving! Although you may be experiencing pain in the inside part of your knee, the culprit could be coming from the ankle. When referring to the "kinetic chain", this describes the limb as a whole. For example, when a deficit or "kink" is in the chain, the joint above or below will compensate for that "kink". Sometimes even multiple joints will compensate! I will later describe in detail why it is important to have adequate ankle dorsiflexion in relation to the kinetic chain for every day activities such as walking, squatting. But first, it's necessary for me to describe the basic anatomy!
The talucrural (ankle) joint involves the talus (ankle bone), tibia (shin bone), and fibula(smaller shin bone). [depicted below] The tibia/fibula extend to help form the knee joint. Therefore, if the tibia/fibula are restricting at the talocrural joint, then guess where it compensates? If you guessed the knee, then you're right! When the knee joint is overcompensating, the force is then transferred upwards toward the hip and lumbar spine causing possible dysfunction.
You see, the talocrural joint is an extremely important joint for proper function of the kinetic chain!
Let's dive a little deeper into the kinetic chain! During gait, the tibia internally and externally rotates. When the talocrural joint is not working properly, limited tibia rotation at the talocrural joint will then cause a majority of rotation to occur at the knee. The knee joint does not allow rotation, therefore this places abnormal and excessive stress on the medial (inside) aspect of the knee. This will then cause the femur (thigh bone) to compensate with internal rotation, leading to excessive hip joint internal rotation. This will then cause abnormal shear on the lumbar spine. Wow!
Knee valgus(depicted below) is the term for when the knee will collapse inward. As you can see in the picture, this will cause abnormal stress on the muscles and ligaments in the medial knee. If the limited ankle dorsiflexion is not addressed, this medial knee pain will continue to progress in severity. Overtime, this will cause weakness in the hips(specifically abductors) and quadriceps musculature.
Walking requires >10 degrees ankle dorsiflexion. Running requires >15 degrees. Squatting requires >20 degrees. You may respond: but I don't workout therefore never squat. Wrong! How do you sit down? How do you pick something up from the ground? You see, adequate ankle mobility is essential for healthy knees during every day activity. Adequate ankle mobility is even more essential for athletes!
To determine if you have limited ankle dorsiflexion, I would suggest scheduling an appointment with your physical therapist for proper evaluation. Following evaluation, they can implement proper exercises and manual therapy. Manual therapy techniques including joint mobilization, soft tissue mobilization, and stretching for the ankle are extremely helpful!
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