Acute Tibialis Posterior Tendon Rupture

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Tendon Rupture · Ankle Trauma

Acute Tibialis Posterior Tendon Rupture

A patient guide by Mr Matthew Welck, Consultant Orthopaedic Foot & Ankle Surgeon, London and North London

The tibialis posterior tendon runs behind the bony bump on the inside of your ankle. It helps hold up the arch of your foot. An acute rupture means the tendon has suddenly torn because of an injury. This usually happens with a broken or dislocated ankle, or a cut to the inside of the ankle. It is rare and easy to miss, but if it is found and repaired early, the results are good. If it is missed, the arch can slowly drop, leading to a painful flat foot. This guide explains this injury and how it is treated in London and North London. If your tendon has worn out slowly over time (adult acquired flatfoot), please see our separate guide.

At a Glance: Acute Tibialis Posterior Rupture

Key factAcute tibialis posterior rupture
What it isA sudden tear of a healthy tendon on the inside of the ankle, caused by an injury
Who it affectsAdults of any age after a bad ankle break or dislocation, a break of the lower shinbone (pilon fracture) or a cut to the inside of the ankle
Main symptomsPain, swelling and bruising on the inside of the ankle after an injury, weakness turning the foot inwards, and being unable to stand on tiptoe on one leg
Key testsExamination, X-rays (a small chip of bone from the inner ankle can be a clue), ultrasound or MRI scan; often found during surgery to fix the broken ankle
First-line treatmentAn operation to repair a complete tear, ideally early; a cast or boot for a partial tear or for people who cannot have surgery
SurgeryStitching the tendon back together or back onto the bone; using a nearby tendon (FDL) if the gap is too big; a bigger rebuild of the foot if the injury is found late
RecoveryAbout 6 weeks in a cast without putting weight on the foot, then a boot and physiotherapy; often guided by how the broken bone heals
EvidenceMainly individual case reports and small studies; results are good to excellent when repaired early, but the injury is often missed at first
01

What Is an Acute Tibialis Posterior Rupture?

Tibialis posterior is a muscle deep in the calf. Its tendon (the tough cord that joins muscle to bone) runs behind the bony bump on the inside of the ankle, called the medial malleolus. It attaches to a bone in the arch called the navicular. It turns the foot inwards, keeps the middle of the foot firm when you walk, and is the main muscle holding up the arch.

An acute rupture is a sudden tear of a tendon that was healthy before the injury. This is different from the much more common problem where the tendon slowly wears out and stretches over months or years. The tendon sits deep and is well protected, so it takes a lot of force to tear it. It usually tears where it bends around the inner ankle bone. Sometimes the torn end gets caught inside the broken bone.

The pain from a broken ankle often hides the tendon injury, so it is often missed at first. If it is not treated, the arch loses its main support and the foot can slowly flatten. If it is found early, the tendon can usually be stitched back together.

02

How Common Is It?

This injury is rare. Since the first report in 1980, only around 35 cases linked to closed ankle fractures (where the skin is not broken) have been described in medical journals written in English. It is probably more common than this, because it is hard to examine an ankle that has just been broken.

Even though it is uncommon, it matters. A 2024 review of the research found that the tendon was trapped in around 16% of pilon fractures (breaks of the lower shinbone), and in most of these cases it was found late.

03

What Causes an Acute Rupture?

  • Broken or dislocated ankle: especially injuries where the foot is forced outwards, and breaks of the inner ankle bone.
  • Pilon fractures: serious breaks of the lower end of the shinbone, where the tendon can be torn or trapped.
  • Cuts: injuries to the inside of the ankle from glass, blades or machinery.
  • Bad twisting injuries: sometimes a severe sprain, including in sport, can tear the tendon without breaking a bone.
  • Missed injury: a tear that is not spotted at the time may show up later as a foot that is slowly becoming flat.
04

What Are the Symptoms?

  • Pain, swelling and bruising behind and below the inner ankle bone after an injury
  • Weakness when turning the foot inwards
  • Difficulty standing on tiptoe on the injured leg, once the broken bone has healed enough to test this
  • A gap behind the inner ankle bone where the cord-like tendon should be felt
  • Weakness in the foot after a cut to the inside of the ankle
  • If the injury was missed: the arch dropping and the heel tilting outwards in the weeks or months afterwards, so that more toes can be seen from behind (“too many toes”)

After an ankle fracture?

If the inside of your ankle stays swollen, or your arch seems to be dropping, after a broken ankle or a cut to the inner ankle, ask for the tibialis posterior tendon to be checked. Repairing the tendon in the first week is a much simpler operation than rebuilding a flat foot months later.

05

What Tests Might You Need?

  • An examination to check the strength of the tendon, although this can be hard while the broken ankle is painful
  • X-rays: a small chip of bone pulled off the inner ankle bone can be a sign that the tendon is torn
  • An ultrasound or MRI scan to confirm the tear, where it is and how big the gap is
  • A check of the tendon during surgery to fix the broken ankle, especially if the broken inner ankle bone will not go back into place, as the tendon may be caught in it
  • A CT scan after complex ankle or shinbone fractures if the tendon may be trapped; X-rays taken standing up, or a Weight-Bearing CT scan, if the injury is found late, to measure how much the arch has dropped
06

Treatment Without Surgery

If the tendon is completely torn and you are active, an operation to repair it is usually advised. This is because the torn ends pull apart and cannot heal at the right length on their own. Treatment without surgery may be suitable if the tendon is only partly torn, or if your general health or activity level means surgery is not right for you.

  • A cast or walking boot for about six weeks, with the foot held slightly turned in, to protect a partial tear
  • A step-by-step strengthening programme with a physiotherapist once the tendon and any broken bone have healed
  • A made-to-measure insole that supports the arch and heel, to take strain off the tendon while it recovers
  • Regular check-ups, ideally with X-rays taken standing up, to make sure the arch is not dropping
  • A referral for surgery without delay if your strength does not come back or the arch starts to drop
  • For people who are less active or not fit for surgery, a made-to-measure ankle brace (such as an Arizona brace) is a good long-term option if the foot later becomes flat
07

Surgery for an Acute Rupture

The aim of surgery is to repair the tendon before the arch has a chance to drop. It is best done early, and is often carried out during the same operation that fixes the broken ankle. The longer it is left, the more the torn ends pull back and scar, and the bigger the operation becomes.

Repairing the Tendon After an Injury

If the tendon is torn along with a broken ankle or a cut, it is repaired during the operation to fix the bone or clean the wound. If the tendon is caught in the break, it is freed. The torn ends are tidied and stitched firmly back together. If the tendon has pulled off the bone, it is fixed back on with a small anchor. The band of tissue that holds the tendon in place behind the ankle bone is repaired as well.

Using a Nearby Tendon When Repair Is Not Possible

If the gap is too big, or the tendon ends are too damaged, a nearby tendon can be used instead. This is the flexor digitorum longus (FDL), which bends the smaller toes. It is joined to the tibialis posterior, or attached to the arch bone, to take over its job. People can still stand on tiptoe afterwards, and most do not notice any weakness in their smaller toes.

If the Injury Is Found Late

If the tear was missed and the arch has started to drop, the foot needs a flatfoot reconstruction. This combines the FDL tendon transfer with an operation to cut and shift the heel bone back under the leg (a medialising calcaneal osteotomy), which protects the new tendon. Sometimes a ligament under the arch, called the spring ligament, is repaired too. Studies show these operations still work well around 15 years later. Each step is planned for your foot, often using a Weight-Bearing CT scan.

Fusion for a Stiff or Worn Foot

If a tear has been missed for a long time and the foot has become stiff, or the joints have become worn (arthritis), the joints at the back of the foot can be fused (joined together). This is called a double or triple fusion, and it reliably corrects the shape of the foot.

Comparing the Main Operations

OptionWhen it is usedWhat to expect
Tendon repairA recent tear with healthy tendon ends, ideally within days to weeksRepairs the tendon before the arch drops; good to excellent results reported
Using a nearby tendon (FDL)A large gap, a damaged tendon or a delayed repairRestores the tendon’s job; you can still stand on tiptoe
Flatfoot reconstruction (FDL transfer + heel bone shift)A missed tear with a flat foot that is still flexibleKeeps the joints moving; good long-term results
Hindfoot fusionA missed tear with a stiff or worn footReliably corrects the shape; some loss of side-to-side movement

Recovery After Surgery

After the tendon is repaired, your foot is put in a cast, pointing slightly down and in, to protect the repair. You usually cannot put any weight on it for about six weeks. This often fits in with the time the broken bone needs to heal. You then move into a walking boot and start physiotherapy to rebuild strength. Getting back to sport and high-impact activity takes several months. Recovery after a late flatfoot reconstruction takes longer, usually nine to twelve months.

As with any operation, there are risks. These include problems with wound healing, irritation of a nerve, the repair stretching or tearing again, slow healing of the broken bone, blood clots and stiffness. Mr Welck will talk these through with you in detail before you make any decision.

08

Why Choose Mr Welck?

Mr Matthew Welck is a Consultant Orthopaedic Foot & Ankle Surgeon at the Royal National Orthopaedic Hospital (RNOH), Stanmore, and Honorary Associate Clinical Professor at University College London (UCL).

Mr Welck’s practice is dedicated to the foot and ankle, with clinics in Central and North London. He works at the RNOH, one of the UK’s leading specialist orthopaedic hospitals, where more complex cases are sent. He regularly treats patients with sudden tendon tears, complex ankle fractures and flat feet caused by missed injuries, including patients referred by other surgeons.

Sports injuries are a large part of his work. Where helpful, a Weight-Bearing CT scan is used to show how your foot looks when you stand on it, and to check the effect of an injury that was missed. He also performs total ankle replacement, complex reconstruction and revision (repeat) surgery, so if a missed tear has affected your joints, everything can be looked after in one place.

Mr Welck is active in research, with more than 50 published scientific papers. He sits on the British Orthopaedic Foot & Ankle Society (BOFAS) Education Committee and teaches senior trainee surgeons how to manage tendon tears. Every treatment plan is agreed together with you.

09

Frequently Asked Questions

What is an acute tibialis posterior rupture?

It is a sudden tear of a healthy tendon on the inside of the ankle, caused by an injury. This is usually a broken or dislocated ankle, or a cut to the inner ankle. It is different from the slow wearing of the tendon that causes most flat feet in adults.

Can it be treated without surgery?

If the tendon is completely torn and you are active, it usually needs an operation, because the torn ends pull apart and cannot heal at the right length. A partial tear, or a tear in someone who is not fit for surgery, may be treated in a cast or boot, followed by an insole or brace.

How do I know if my tendon has ruptured?

Common signs are pain, swelling and bruising on the inside of the ankle after an injury, weakness turning the foot inwards, and being unable to stand on tiptoe on that leg. A broken ankle can easily hide these signs, so an ultrasound or MRI scan, or a check during surgery, confirms the diagnosis.

Can the tendon tear when I break my ankle?

Yes. It is uncommon, but the tendon can be torn or trapped with some ankle and shinbone fractures, and it is often missed at first. Repairing it early is much simpler than rebuilding the foot later.

How soon should the tendon be repaired?

Ideally within the first few days or weeks, often during the same operation that fixes the broken ankle. If it is left, the torn ends pull back and scar, and a nearby tendon may need to be used instead.

How long does recovery take after the tendon is repaired?

Usually about six weeks in a cast without putting weight on the foot, then a boot and physiotherapy. Recovery often depends on how the broken bone heals, and getting back to sport and full strength takes several months.

What happens if the tear is missed?

The arch can slowly drop over the following months. Treatment is then a flatfoot reconstruction using a nearby tendon and an operation to realign the heel bone, or a fusion if the foot has become stiff or worn.

Where can I see a foot and ankle surgeon in London about a tendon rupture?

Mr Matthew Welck sees patients at HCA The Princess Grace Hospital in Central London, and at Spire Bushey, HCA The Wellington Hospital Elstree and the RNOH Private Patients Unit in North London.

10

Book a Consultation

If you still have pain or weakness on the inside of your ankle, or your arch seems to be dropping, after a broken ankle, sprain or cut, it is best to see a specialist early. This gives you the widest choice of treatment. Mr Welck sees private patients (insured and self-funding) and NHS patients at the following locations:

  • HCA The Princess Grace Hospital, Central London (outpatients at Nottingham Place, W1U 5NY and 30 Devonshire Street, W1G 6PU)
  • HCA The Wellington Hospital Elstree, North London
  • Spire Bushey, North London (0203 733 5665)
  • RNOH Private Patients Unit, Stanmore, North London

Telephone 07547 395 270, email secretary@matthewwelck.com or book a consultation online. Patients are seen from across London, Hertfordshire, the UK and overseas.

Written and medically reviewed by Mr Matthew Welck

MBChB FRCS (Tr&Orth), Consultant Orthopaedic Foot & Ankle Surgeon, RNOH Stanmore; Honorary Associate Clinical Professor, UCL. GMC 6074385.

Last reviewed: October 2026. Next review due: October 2027.

References

  1. Magan P, Chin See C, Clarke D, Patel F, Senn D. Rupture of the tibialis posterior tendon with associated bimalleolar ankle fracture. Cureus 2022;14:e31886.
  2. West MA, Sangani C, Toh E. Tibialis posterior tendon rupture associated with a closed medial malleolar fracture: a case report and review of the literature. J Foot Ankle Surg 2010.
  3. Bernstein DT, Harris JD, Cosculluela PE, Varner KE. Acute tibialis posterior tendon rupture with pronation-type ankle fractures. Orthopedics 2016.
  4. Malik AK, Mehta S, Solan M. Significance of flake fracture with medial malleolar fracture. Foot Ankle Int 2013.
  5. Chadwick C, Whitehouse SL, Saxby TS. Long-term follow-up of flexor digitorum longus transfer and calcaneal osteotomy for stage II posterior tibial tendon dysfunction. Bone Joint J 2015;97-B:346–52.
  6. Syziu A, Aamir J, Mason LW. Posterior tibialis tendon entrapment as a complication of posterior malleolar fractures in complex ankle fractures: a systematic review. Bone Jt Open 2024;5:252–9.

This guide is for general information and does not replace an individual consultation. Treatment decisions should be made with a clinician who has examined you.

Written by: Matthew Welck | Consultant Orthopaedic Foot & Ankle Surgeon London — last updated 24 October 2026

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