Inner ankle pain: Causes and How to Make a Diagnosis

Inner ankle pain — also called medial ankle pain — is common in active people and athletes. The inner ankle is a complex region of bones, tendons, ligaments, and nerves, which makes it prone to a range of injuries. So what causes pain on the inside of the ankle, and how do we diagnose it?

Common causes of inner ankle pain 

Tibialis posterior tendonitis

The tibialis posterior tendon supports the arch of the foot. Overuse leads to degeneration and partial tearing, causing pain and swelling on the inner ankle — typically with weight-bearing, walking, and running. Left untreated, it can progress to a flatfoot deformity.

Inner ankle sprain (deltoid ligament)

Less common than lateral ankle sprains, a medial ankle sprain occurs when the deltoid ligament on the inner side is overstretched or torn — usually from the ankle rolling inward. It causes pain and swelling on the inside of the ankle.

Accessory navicular syndrome

An accessory navicular is an extra bone or cartilage on the inner side of the foot, near the navicular. An ankle sprain can disrupt the junction (synchondrosis) between the two, causing focal pain and swelling near the navicular bone.

Ankle joint arthritis

Osteoarthritis or inflammatory ankle arthritis causes medial ankle pain, more often in older people or those with a history of ankle injury.

Ankle stress fractures

Stress fractures of the medial malleolus or nearby bones, such as the navicular, talus, or calcaneus, develop from repetitive impacts, such as running. They cause localised pain that worsens with activity, and — as they progress — pain at rest and at night.

Less common causes of inside ankle pain

Tarsal tunnel syndrome

Tarsal tunnel syndrome occurs when the tibial nerve is compressed as it runs through the tarsal tunnel on the inner ankle. It causes burning pain, tingling, or numbness along the inner ankle and into the foot.

Tarsal coalition

Tarsal coalition is an abnormal connection between two ankle bones — most often the talus and calcaneus. It alters the forces through the ankle, causing pain and swelling.

Flexor tendonitis

The flexor tendons — flexor hallucis longus and flexor digitorum longus — can become inflamed from overuse. Pain typically occurs with toe flexion or pushing off.

Referred pain from the spine

Occasionally, nerve impingement in the lumbar spine refers pain to the inner ankle. The giveaway: touching the ankle doesn’t reproduce the pain, and there may be other nerve symptoms such as numbness, pins and needles, or weakness.

How is inner ankle pain diagnosed?

An accurate diagnosis of medial ankle pain rests on a thorough clinical assessment, supported by imaging when needed.

Your doctor first takes a history — the onset, duration, and aggravating and relieving factors, along with any recent injury or change in activity, and other symptoms such as swelling, tingling, numbness, or back pain. Examination of the ankle then looks for swelling, tenderness, and weakness, with a neurological assessment where relevant.

Imaging confirms the diagnosis:

• X-ray — identifies fractures, bony abnormalities, or arthritis, though it often misses stress fractures

• Ultrasound — shows the soft-tissue structures such as tendons and ligaments, detecting tears or inflammation

• MRI — the best test for stress fractures, and for detailed soft-tissue and bone imaging

• CT — for assessing bony structures in detail, or when X-ray or MRI is inconclusive

• Nerve conduction studies / EMG — occasionally needed for nerve-related pain

How is inner ankle pain treated?

Treatment depends entirely on the cause — which is why an accurate diagnosis comes first. Tendon problems such as tibialis posterior tendonitis respond to rehabilitation, orthotics, and sometimes an ultrasound-guided injection; ligament sprains to a graded rehabilitation programme; stress fractures to a period of offloading; and nerve entrapments such as tarsal tunnel syndrome to a combination of activity modification, injection, or in some cases surgery. Getting the diagnosis right is what allows the right treatment.

Frequently asked questions about inner ankle pain

What is the most common cause of medial ankle pain?

In active people, tibialis posterior tendonitis is one of the most common causes of inner ankle pain and swelling during walking and running. It can flatten the arch over time if it’s ignored. But several conditions cause very similar pain, so an accurate diagnosis matters.

When should I worry about inner ankle pain?

See a doctor promptly for pain that worsens with impact and continues at rest or at night (a possible stress fracture), for burning, tingling, or numbness (a possible nerve problem such as tarsal tunnel syndrome), or for pain after a significant sprain that isn’t settling. Persistent or worsening inner ankle pain always deserves assessment.

Why does my inner ankle hurt but nothing shows on X-ray?

X-rays frequently miss stress fractures and don’t show soft-tissue problems such as tendon or ligament injury at all. If your X-ray is normal but the pain persists, an ultrasound or MRI usually finds the cause.

Can inner ankle pain come from my back?

Yes. Nerve irritation in the lower back can refer pain to the inner ankle. The clue is that pressing on the ankle doesn’t reproduce the pain, and there may be numbness, tingling, or weakness — which is why a neurological assessment is sometimes part of the work-up.

How is inner ankle pain treated?

It depends on the cause — rehabilitation and orthotics for tendon problems, offloading for stress fractures, graded rehab for sprains, and specific treatment for nerve entrapment. The first and most important step is an accurate diagnosis.

Explore inner ankle and foot pain by location.

Final word from Sport Doctor London about inner ankle pain

Inside ankle pain has many causes, from tendon and ligament injuries to nerve entrapment and stress fractures. Because these conditions cause similar symptoms but need very different treatment, an accurate diagnosis is essential. Early assessment prevents complications — such as the flatfoot deformity that can follow untreated tibialis posterior tendonitis — and speeds recovery.

If you have persistent inner ankle pain, Dr Masci can assess you in London, including ultrasound in clinic. Contact the team here or call +44 (0) 203 488 0350.

Related conditions: 

• Tibialis posterior tendonitis
• Deltoid ligament sprain (medial ankle sprain)
• Accessory navicular syndrome
• Tarsal tunnel syndrome
• Navicular stress fracture
• Foot pain chart