Overview
Posterior tibial tendon dysfunction is a problem with the posterior tibial tendon, a key structure that helps support the arch of your foot and stabilizes the inner side of your ankle. When the tendon becomes irritated, weakened, or degenerates, the foot may slowly lose its normal arch. This can lead to pain on the inside of the ankle and increasing difficulty walking, especially on uneven ground or for long periods. Over time, some people develop a progressive flatfoot that can change how the foot absorbs impact.
Symptoms
People often notice pain along the inside of the ankle and sometimes extending toward the arch. Swelling may occur around the tendon, and the area can feel tender when pressed. Symptoms are commonly worse with standing, walking, climbing stairs, or pushing off, and may improve with rest. As weakness progresses, you may notice flattening of the arch, a shift of the foot inward, fatigue in the lower leg, and reduced ability to do activities that require prolonged weight-bearing.
Causes
Posterior tibial tendon dysfunction usually develops from tendon overload over time, where the tendon can no longer handle the stress placed on it. This can be caused by repetitive strain, foot mechanics that increase tendon strain, or gradual degeneration of the tendon. In some cases, an acute injury or sudden worsening can trigger the beginning of symptoms, but many cases are related to chronic wear and abnormal loading. The result is impaired tendon function and loss of arch support.
Risk Factors
Your risk is higher if you have flat feet or low arches, because the tendon must work harder to support the arch. It is also more common with age-related tendon degeneration and in people who are significantly overweight, since body weight increases stress on the tendon. Prior ankle injury, decreased flexibility of the calf/heel, and activities that involve frequent long periods of standing or walking can contribute. Diabetes and inflammatory conditions can also affect tendon health and healing capacity in some individuals.
Prevention
You can lower your risk by supporting healthy foot mechanics and avoiding sudden increases in time spent on weight-bearing activity. Wearing well-fitting shoes with good arch support and using orthotics when needed can reduce tendon overload. Regular calf stretching and strengthening of the foot and ankle muscles can improve load tolerance. If you have early symptoms, reducing painful activities and addressing biomechanics with professional guidance can help prevent progression.
How the Diagnosis Is Evaluated
Clinicians usually start with a detailed history of pain location, activity triggers, how symptoms changed over time, and any prior ankle injuries. A physical exam focuses on tenderness along the posterior tibial tendon, evaluation of foot arch height, observation of foot alignment, and strength testing, often including single-leg movements. Doctors may assess flexibility of the calf and check for other causes of inner ankle pain. Imaging such as X-rays can be used to look at arch position and arthritis, and ultrasound or MRI may be ordered when tendon damage, tears, or other soft-tissue problems are suspected; not every patient needs advanced imaging.
Nonsurgical Treatment Options
Nonsurgical treatment aims to decrease tendon stress, calm inflammation, and support the arch while the tendon recovers or adapts. Footwear changes and orthotics, including custom or over-the-counter arch supports and structured inserts, can improve alignment and reduce pain during walking. Bracing such as an ankle-foot orthosis (often a rigid or semi-rigid brace) may be recommended to stabilize the tendon and limit harmful motion. Physical therapy commonly includes stretching of the calf, strengthening of the posterior tibial tendon and surrounding muscles, and gait or biomechanics training. Anti-inflammatory medicines may be used for symptom control, and corticosteroid injections are sometimes considered selectively when pain is persistent, typically with careful clinician guidance due to potential tendon risk. In some cases of chronic pain that does not improve, clinicians may discuss biologic options such as platelet-rich plasma (PRP) injections, though evidence varies by situation and tendon condition.
When to Seek Medical Attention
Seek prompt medical attention if you cannot bear weight, if pain and swelling rapidly worsen, or if you notice a sudden change in foot shape or alignment. You should also be evaluated urgently if there is fever, significant redness or warmth suggesting infection, or severe pain out of proportion to activity. Get medical care sooner if weakness is progressing, the arch is collapsing quickly, or you develop numbness, new tingling, or other neurologic symptoms. If symptoms persist despite rest and conservative care, a timely appointment helps prevent progression and preserves function.
Frequently Asked Questions
It often feels like aching or sharp pain along the inside of the ankle and arch, sometimes with swelling and tenderness over the tendon. | Can I still walk with posterior tibial tendon dysfunction?
Some people progress over time, especially if the tendon becomes more weakened, but early nonsurgical support can slow or reduce symptoms. | How long does conservative treatment take to work?
Not always; diagnosis is usually made with history and physical exam, and imaging like X-rays or MRI is used when needed to confirm the cause or assess tendon damage.
Next Steps
If you are having persistent inner ankle pain, swelling, or changes in your arch, start by reducing painful weight-bearing activities and using supportive footwear. Schedule an evaluation with a clinician or physical therapist for an exam and a plan tailored to your severity and foot alignment. Seek care sooner if you cannot bear weight or your symptoms are rapidly worsening.