Posterior Ankle Impingement Syndrome: Symptoms, Causes, and Treatments

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Posterior ankle impingement syndrome (PAIS) is a condition that causes deep pain in the back of the ankle when the foot is pointed downward (plantar flexed). This problem typically arises when a piece of excess bone, a muscle, or a ligament pinches against another anatomical structure in the hindfoot.

Depending on the severity, PAIS can significantly limit ankle range of motion and make certain athletic movements like rising up on your toes or pushing off your foot very painful. This article will detail the symptoms, diagnosis, and treatment of posterior ankle impingement syndrome.

Ballet dancer feeling pain in foot and ankle

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Who Is at Risk?

Posterior ankle impingement syndrome is most commonly seen in athletes who participate in activities that involve repetitive ankle plantar flexion. This includes soccer players and ballet dancers, who frequently rise up onto their toes in the en pointe position. Cross-country or trail runners who do high volumes of downhill running are also at a higher risk.

In these athletes, PAIS can occur after an acute or forced plantar flexion movement or as a result of repetitive plantar flexion over a longer period of time.

The condition can also arise in nonathletes, though this is much less common. In these people, posterior impingement usually occurs as a result of a bone abnormality that causes pinching of the tissue in the hindfoot.


Several hallmark characteristics help differentiate posterior ankle impingement syndrome from other pain-causing conditions. The pain from this condition is typically deep in the back of the ankle and brought on by rising onto the toes or pointing the foot downward.

The soreness is typically worst as you participate in the dance or sport, though an ache may linger even after the activity is completed. Individuals with PAIS may describe their pain as sharp, dull, constant, or radiating, though they usually have difficulty pinpointing its exact location.

Range of motion is also commonly restricted, and a noticeable difference in downward flexion may be appreciated between the affected and unaffected foot. Swelling and redness may also be present in the hindfoot area if a more acute plantar flexion injury occurs.


Several other ankle conditions, including Achilles tendonitis and posterior tibial tendonitis, can cause hindfoot symptoms similar to the ones from PAIS. Because of this, it is important to have your foot evaluated by a healthcare provider to make a proper diagnosis.

Typically, a healthcare provider will begin with a physical examination of the ankle. A posterior ankle impingement test, in which the healthcare provider passively flexes the foot downward and assesses for pain, is usually performed. The absence of symptoms during this technique makes a PAIS diagnosis much less likely.

In addition, several types of diagnostic images may be ordered. X-rays are useful when looking for a bone abnormality or an accessory bone (called an os trigonum) that can lead to impingement. A computed tomography (CT) scan may also be indicated, especially if surgery is planned, to visualize the bones in the region more reliably.

Magnetic resonance imaging (MRI) is occasionally used to examine the soft tissue in the hindfoot (including ligaments, muscles, and the joint capsule) if pinching these structures is thought to be the origin of your pain.


In up to 60% of cases, conservative treatment effectively resolves the symptoms of posterior ankle impingement syndrome. Typically, nonsurgical interventions include:

Surgical Procedures

In approximately 40% of cases, conservative care is not effective and surgery is needed. The type of operation that is performed varies depending on the origins of your ankle pain.

When the impingement is caused by a bony buildup on the ankle’s talus bone or by a piece of accessory bone in the area (os trigonum), arthroscopic surgery is typically performed.

During this operation, the symptom-causing section of the bone is cut away or removed. This helps resolve any posterior impingement, reduce your pain, and increase the available range of motion in the ankle.

In the case of soft-tissue-caused impingement, arthroscopic surgery may also be used to debride the ligament or muscle that is being pinched. Typically, your surgeon will passively plantar flex your foot during the procedure and watch the various structures in the hindfoot to confirm which is being pinched.

Following this visual examination, an arthroscopic shaver is used to remove the offending portion of soft tissue and resolve the PAIS.


Posterior ankle impingement syndrome is a condition that causes deep, hard-to-pinpoint pain in the back of the ankle. This issue is most commonly seen in dancers and athletes whose sport involves repetitive plantar flexion, though it may also occur in non-athletes with bone abnormalities of the hindfoot.

Conservative care effectively treats many PAIS cases, though surgery may be needed if the pain persists. A thorough physical exam and imaging are usually necessary to properly diagnose this issue.

A Word From Verywell

Posterior ankle impingement is a frustrating condition that can affect your ability to compete at the highest levels of your sport or activity. While it may be tempting to ignore the pain in your hindfoot and continue exercising, it is important to listen to your body.

Having your pain properly diagnosed by a medical professional helps narrow down the appropriate treatment options and can speed up your eventual recovery. While this sometimes means surgery, in many cases, conservative care alone is enough to return you to the activities you love.

Frequently Asked Questions

  • Do I need surgery for posterior ankle impingement?

    In approximately 60% of cases, conservative treatment is all that is needed to treat posterior ankle impingement. This typically involves ice, rest, activity modification, pain-relieving medications or injections, and physical therapy. About 40% of the time, however, these treatments are ineffective, and surgery is warranted.

  • How do I know if my pain is posterior impingement or Achilles tendonitis?

    The pain from posterior ankle impingement is typically located deep in the back of the ankle and is difficult to pinpoint. It can be sharp during activities that involve repetitive plantar flexion, though dull pain can continue afterward.

    The pain from Achilles tendonitis, on the other hand, is typically more focal (over the Achilles itself or near the tendon’s insertion into the heel bone). The symptoms of this condition are usually worst during the first steps of the day or at the end of a run or strenuous exercise.

  • What is os trigonum?

    Os trigonum refers to a piece of accessory bone (one that doesn't form in all people) that is located in the back of the ankle. This condition, which is present in approximately 25% of the healthy population, is typically asymptomatic. Occasionally, however, the extra piece of bone can begin to pinch the other structures in the area and can lead to posterior ankle impingement syndrome.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Yasui Y, Hannon CP, Hurley E, Kennedy JG. Posterior ankle impingement syndrome: a systematic four-stage approach. World Journal of Orthopaedics. 2016;7(10):657. doi:10.5312/wjo.v7.i10.657

  3. Sugimoto K, Isomoto S, Samoto N, Matsui T, Tanaka Y. Arthroscopic treatment ofposterior ankle impingement syndrome: mid-term clinical results and a learning curve. Arthroscopy, Sports Medicine, and Rehabilitation. 2021;3(4):e1077-e1086. doi:10.1016/j.asmr.2021.03.013

By Tim Petrie, DPT, OCS
Tim Petrie, DPT, OCS, is a board-certified orthopedic specialist who has practiced as a physical therapist for more than a decade.