Everything You Need To Know About Tarsal Coalition

What Is A Tarsal Coalition?

A tarsal coalition is problem of the back part of the foot (involving the tarsal bones) where the bones are abnormally grown together (fused) resulting in a loss of normal motion.  The foot may be painful, stiff/rigid, develop arthritis and be associated with a flat foot.


Tarsal Coalition - Middle Facet Talocalcaneal Tarsal Coalition Calcaneonavicular



What Causes A Tarsal Coalition?

A tarsal coalition is generally an an inherited genetic condition.  Tarsal coalition has been identified in the fetus, indicating the congential nature of the condition.   It is most commonly first identified in teen-age children.  Sometimes, tarsal coalitions may be due to injury where the bones become damaged and grow together.  In rare cases, it may be associated with systemic arthritic conditions.


What Is The Natural History Of Tarsal Coalition? Will It Get Better?

Not all tarsal coalitions are painful and symptomatic.  Because the tarsal coalition locks the bones together and restricts normal motion, the foot may adapt over time and symptoms may subside.  It is important to understand, that as long as the tarsal coalition remains it is impossible for the rearfoot to move.  Tarsal coalition can also lead to arthritis and other structural derangement of the foot and ankle due to abnormal biomechanics.


Tarsal Coalition Anatomy: Rearfoot Anatomy?

Tarsal coalitions affect the tarsal bones of the rearfoot.  There are three tarsal bones:

  1. Calcaneaus (heel bone)
  2. Talus (foot portion of ankle joint)
  3. Navicular (foot bone)


How are Tarsal Coalitions Classified?

Tarsal coalitions are classified by three things:

  1. The bones that are involved/bound together:

    • Talocalcaneal
    • Calcaneonavicular
    • Talonavicular
  2. The type of tissue that binds the bones together:

    • TalocalcanealFibrous (scar tissue)
    • Osseous (bone)
  3. Whether or not the Coalition involves a joint:

    • Intra-articular (occurs within a joint)
    • Extra-articular (occurs outside of a joint)


What Are The Symptoms Of Tarsal Coalition?

People with tarsal coalition may have pain in their foot.  The pain can be severe and achy to superficial and mild.  The pain can be widespread in the foot, or be more focally located directly at the rearfoot where the coalition is.  Muscle spasms may occur as a response to the restricted motion, and specifically involve the peroneal muscles.  Coalitions often also cause a rigid flat foot – which independently be a tremendous source of arch pain and heel pain.   Severe flat feet may drive the heel bone into the outside of the ankle bone as well as  irritate/damage tendons on the outside of the heel.  Coalitions can develop arthritis in the rearfoot causing achy pain.


What Is A Tarsal Coalition Flatfoot?

It is well know that coalitions can cause flat feet depending on the position the foot bone fuse together.  They cause a rigid flat foot (different than a flexible flat foot) which means the foot position remains flat regardless of whether or not weight is placed on it.  Essentially the foot is stiff, or as its name implies rigid.  The foot can have a collapsed arch, displaced heel bone and/or the forefoot being pushed outwards in a duck-like fashion.  Rigid flat feet associated with tarsal coalition can be very painful.


What is Tarsal Coalition Arthritis?

Arthritis may form within the rearfoot as part of the tarsal coalition, or it may develop with time from improper structural alignment.   Arthritis can form even in children and adolescents.  Dr. Blitz’ award winning research identified that coalition associated arthritis is more common with fibrous coalitions that allow some micromotion and arthritis progresses with age. The presence of arthritis often determines the type of surgery that will be recommended.


How Are Coalitions Diagnosed?

Sadly coalitions may go undiagnosed for a long time in many people.  There are several reasons, but usually due to two reasons: 1) doctors not recognizing the condition, and 2) parents not fully recognizing the foot problem in their children and getting them to a foot and ankle specialist.  The earlier the diagnosis is made the better chance there is for treatment, especially when it involved surgery.

Tarsal Coalitions are diagnosed with a combination of the clinical exam performed by a healthcare professional, xrays and advanced radiologic studies (MRI, CT, bone scans).


What Does the Clinical Exam Reveal in Tarsal Coalition?

  1. Stiff Rearfoot

    The nature of tarsal coalition involves the bone of the back part of the foot being fused together which means the bones cannot move against each other.  This creates a stiff rearfoot.

  2. Flat Feet

    The present of flat feet (or a single flat foot) may alert the doctor to the possible presence of a tarsal coalition – especially with rigid flat feet.  Some tarsal coalition flat feet can be severe while others mild.  Not all tarsal coalitions are associated with flat feet.

  3. Tight Heel Cord

    A Tight heel cord, a condition medically known as Equinus, often occurs with flat feet, and therefore can also occur with tarsal coalition.  The heel cord is formed from two leg muscles – the Gastrocnemius and the Soleus.  When these muscles become tight they can promote flat feet.  Additionally, when rigid flat feet are present, the muscles contract and are effectively shorter and tighter.

  4. Focal Pain

    On exam several areas of the foot may be painful depending on the location of the coalition, type of coalition, compensatory measures and/or the presence of a flatfoot.  In Dr. Blitz’ experience fibrous coalitions tend to be more painful directly to touch because they are not solidly fused and have the ability for micro motion, which can cause pain and inflammation.  Flat feet may develop pain in the arch region from direct pressure of the collapse or through muscle spasms.  Also, it is common to have pain where the foot meets the ankle in a region anatomically called the sinus tarsi which is located on the outside of the foot.

  5. Muscle Spasms

    Because tarsal coalitions stop normal motion and may be present with a structural foot deformity (flat feet), specific muscles may go into spasm which may be painful and/or further exacerbate structural foot problems.  Specifically, a peroneal muscle spasm is most common, which is a muscle on the outside of the leg that works to pull the foot outwards.

On exam several areas of the foot may be painful depending on the location of the coalition, type of coalition, compensatory measures and/or the presence of a flatfoot.


What Do The Xrays Reveal in Tarsal Coalition?

Radiographs (or X-Rays) can commonly detect a tarsal coalition, however some coalitions can be illusive.  Depending on the coalition, the the xrays may demonstrate different findings:

  1. Calcaneonavicular Tarsal Coalition

    • Coalition Itself Is Easily Seen

      • Calcaneonavicular coalition develop between the calcaneal and navicular bones, and because these two bone don’t share a common joint and don’t articulate with each other the coalition occurs outside of the joint (extra-articular) and is often readily visible.
      • The best way to visualize the calcaneonavicular coalition is on the oblique radiographic view of the foot – specifically the medial oblique view.
    • Anteater sign

      • This is a description of the appearance of the front of the calcaneal bone (heel) in the presence of a coalition.  The bone becomes coned so that it resembles that of an anteater.
      • The best way to visualize the anteater sign of the calcaneonavicular coalition is on the side radiographic view of the foot – specifically the lateral view.
    • Talar beaking

      • This a description of the extra bone growth (bone spur) that forms on top the the talus bone at the talonavicular joint.  It is speculated to develop from strain placed on this joint from an underlying coalition.  This can occur with any type of tarsal coalition.
  2. Middle Facet Tarsal Coalition

    • Coalition Itself is Not Easily Seen

      • Middle facet tarsal coalitions develop between the talar and calcaneal bones, and form within this shared joint (intra-articular) called the subtalar joint, and not readily visible on standard radiographic imaging of the foot.
      • Occasionally the coalition can be readily seen on a special radiographic view called the  harris-beath or “ski jump” view.  With this technique the coalition can be identified as it become directly in the line of sight.
    • C-sign

      • This is a radiographic illusion of the letter “C” that is seen on the side view xray of the foot (lateral).  A “C” shape is seen between the talus and calcaneal bones.  This occurs because the two bone are connected the bones overall become more visual on xrays (radiodense) at the location of the middle facet coalition.
    • Talar beaking

      • This a description of the extra bone growth (bone spur) that forms on top the the talus bone at the talonavicular joint.  It is speculated to develop from strain placed on this joint from an underlying coalition.  This can occur with any type of tarsal coalition.

What Is The Best Advanced Imaging Study For Tarsal Coalition? What do they Show?

The three possible advanced imaging studies that a foot health professional may order when diagnosing, evaluating and/or surgical planning are MRI, CT and/or bone scan.  Each has their advantages and disadvantages.

  • Computed Tomography (CT Scan)

    • CT is best for bone anatomy and structure.  This study allows the visualization of the the joints and bones deep within the foot.  Some CT allow for 3-D reconstruction. Boney coalitions can be readily identified.  The size of the coalition can also be determined.  Additionally, the integrity of the adjacent joints can also be evaluated.
    • CT is very helpful for diagnosis and well as surgical planning
  • Magnetic Resonance Imaging (MRI)

    • MRI is best for soft tissue anatomy, and also allows for bone anatomy.  MRI also allows for the detection of bone edema (fluid accumulation in the bones commonly associated with inflammation).
    • Tarsal Coalitions with bone edema may be a clinical indicator of severity and/or degeneration.
    • MRI is very helpful for diagnosis, surgical decision making and/or surgical planning.
  • Three Phase Bone Scan

    • Bone scan is less commonly ordered for tarsal coalition.  Bone scans detect bone activity and turn-over and may be an indicator of clinical severity and/or degeneration.

When to Seek Treatment For Tarsal Coalition

Common reasons patients seek treatment are: foot becomes painful, interferes with walking or activities, experiences difficulty fitting shoes, swelling, calluses/corns and/or notice a change in appearance of the foot and/or toe(s).

Non-Surgical Treatment For Tarsal Coalition

This portion of Dr. Blitz’ website is dedicated to the non-surgical treatment of tarsal coalition.   Because tarsal coalition is a structural boney problem the underlying issue where bones are fused together, the non-surgical measures for tarsal coalition are aimed at decreasing and/or eliminating symptoms (pain).  Only surgery can remove the boney blockage.  But not all tarsal coalitions require surgery, so there are useful treatment techniques.

Simple Treatments Patients Can Do:

  • Wear proper supportive shoes
  • Modify your activities
  • Lose weight

Non-surgical Treatments Dr. Blitz can add:

  •  Prescribe an oral anti-inflammatory medication
    Anti-inflammatory medication is useful to significantly reduce pain and inflammation.  This may be particularly helpful in managing the  symptoms associated with tarsal coalition arthritis.
  • Physical therapy
    A physical therapist may help keep surrounding joint mobile which is important with tarsal coalition.  A therapist may perform ultrasound and other techniques to reduce inflammation. Stretching of the foot and calf muscles are particularly important with tarsal coalition as they can perpetuate structural foot problems.  If muscle spasms are present, deep massage may help alleviate symptoms.
  • Prescribe protective pads
    Prominent areas of the foot may become irritated and inflamed.  Padding and/or cushioning may provide some general relief.  of the ball of the
  • Prescribe custom foot orthotics
    Foot orthotics (or arch supports) can be very helpful with tarsal coalition – in the presence of a well aligned foot or a flat foot.  A custom foot orthotic (a doctor prescribed arch support) is made directly from a casting (mold) of your feet, and is probably advantageous with the tarsal coalition patient since the shape of the back part of the foot is rigid and fixed as there is no mobility.  The orthotic may help alleviate additional arch and foot strain but again is not expected to change the structure.
  • Give cortisone injection
    A cortisone injection is a powerful anti-inflammatory medication used to rapidly reduce the pain associated with an inflamed area and/or joint. Any pain relief that is experienced from the cortisone injection(s) is often temporary.  This is a short term option and prolonged repeated use of cortisone injections may be detrimental to bone and joint health.
  • Superficial Peroneal Nerve Block
    Patients who have peroneal muscle spasms may benefit from a superficial peroneal nerve block.  The superficial peroneal nerve controls the peroneal muscles and providing an anesthetic block to this nerve temporarily releases the tension in these muscles.  Peroneal spasms can worsen a flat foot deformity associated with tarsal coalition.  if the underlying condition of tarsal coalition is not treated (removed) then the spam will likely return.