Posterior Tibialis Tendonitis

Tibialis posterior tendonitis is an injury that affects a few runners a year. This injury affects mostly people who have pes planus ( flat feet) and/or over pronate. Tibialis posterior tendinitis is painful on the inside of the foot and ankle region. The most stress is during mid-stance, when body weight is fully on the foot. 

What contributes to Tibialis posterior tendonitis?

Limited ankle dorsiflexion

Dorsiflexion is the movement of your foot towards your body, or in standing, when the shin bone moves over the foot. Dorsiflexion is required for proper walking and running mechanics. When the ankle is limited, the body makes up the motion elsewhere. One compensation is the foot splays outward. This will increase stress to plantar fasciitis and posterior tibialis tendon. Over time, the stress leads to injuries of those structures as it is unable to tolerate the load.

The top picture shows the ankle joint when the foot is pronated.
The bottom picture shows the ankle joint when the foot is
supinated. Less ankle dorsiflexion is shown when the foot is
pronated. The motion is taken up at the foot stretching the
tibialis posterior.

What contributes to limited ankle dorsiflexion? 

High Heels

When you wear heeled shoes, the foot is constantly pointed downward in plantarflexion. Over the course of the day the ankle joint progressively stiffens in that position. Even if you’re sitting with your shoes on, the foot is always pointed down. When you are out of the heel shoes and in running shoes, your heels are now closer to the ground. This requires more dorsiflexion at the ankle joint and muscle length of the calf. In order for the body to move over the foot,  the ankle needs to bend. But when ankle dorsiflexion is lacking, the motion is achieved by bending at the foot, specifically the navicular bone. This is the bone which the tibialis posterior tendon attaches to. With each step, the tendon is getting stretched. Over time this strain leads to tendonitis.

Prior Injuries 

Have you ever had a mild ankle sprain that you just ignored? There was a little swelling and pain but symptoms subsided. The swelling limits your ankle mobility and within a couple of days your ankle will get stiff. Your body compensates by getting the motion in your foot. Over time the mobility of the ankle will be more limited. Like above, the tibialis posterior tendon gets stretched. 

Weakness of Glutes 

Our body is connected by muscles, fascia and bones. If there is weakness in one region, it can affect another body part several joints away. The gluteals can affect the ankle. One of the functions of the gluteals is to externally rotate the thigh. Since the femur is attached to the shin, the lower leg bone will lift the arch up when the glutes contract. When the glutes are weak, the femur rotates in, which causes the lower leg to rotating in. This will allow the arches flatten. Try this at home.  Squeeze your glutes and watch what your foot does. 

Pelvic Mal-alignment

The pelvis is made of the ilium on each side and is separated by the pubis in the front and sacrum in the back. The ilium moves independently but one side affects the other.

When the pelvis is rotated, the hip socket, which is on the illium, moves up or down relatively. This affects the entire leg. When one illium rotates backwards, it makes the leg longer and the other leg shorter. This is called a functional leg length discrepancy. There there is actual difference in the length of the leg bone, it is called anatomical leg length discrepancy. This causes a problem for the body because it wants to stand level. The side that longer will pronate while the side that is shorter will supinate. The prolong pronation will stretch the tibialis posterior tendon. 

Placing the book under my foot, makes my leg functionally longer. My right foot is
pronated and the heel is angled away. 

Running Form 

Landing excessively on the outside of
the foot increases stress to the Tibialis
Posterior tendon.

Landing equally across the foot decreases
the stress to the Tibialis Posterior tendon.

Normal running form is to strike the ground on the outside of the foot, then roll to the inside. This is called pronation. However, some runners strike the ground too far on the outside portion of the foot.This places a lot of stress on the tibialis posterior tendon whose role is to slow down pronation. The more the foot strikes on the outside,  the tibialis posterior has to work more to control the motion. 

Treatment

1) Improving ankle mobility and strength will decrease strain on the tibialis posterior tendon. Follow the video in this blog post. 

2) Gluteal and core strengthening program is important to indirectly control the lower leg. There are numerous post on how to strengthen the core. The core video in this post is a great progression. 

3) Correct a pelvic malalignment

Put your hands on your hips and feel for a bony landmark on each side with your thumbs. This landmark is called posterior superior iliac spine, PSIS for short. If your right side is lower, that leg is functionally longer (shown above). If your left side is lower, that leg is functionally longer.



To correct a right posteriorly rotated SI joint, we are going to use the right hip flexors to rotate the illium forward and counter using the glutes/hamstrings to rotate the left side backwards. Lay on your back with your knees bent. Bring your right leg up and use your hands to resist at the knee. At the same time dig your left heel into the ground. Hold this for 6 seconds and repeat 3 times. Next take a hard object ( I like using my foam roller) and squeeze between your knees for 6 seconds 3 times. 

4) Form
Practice landing with equal force across the foot. This decreases the distance the medial side part foot has to lower to the ground which will lessen the stress to the tibialis posterior tendon.


These are some of the contributing factors I look at when assessing a runner with tibialis posterior tendonitis. 

Please let me know if you have any questions.