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Tarsal Coalition

What Is Tarsal Coalition?

Tarsal coalition is an abnormal connection between 2 or more bones in the foot.

The connecting tissue can be either fibrous tissue, cartilage or bone and is commonly found in the hindfoot or midfoot.

The most commonest coalitions are:

  • Talocalcaneal – the talus (ankle bone) and calcaneus (heel bone) have not separated
  • Calcaneonavicular – an abnormal connection exists between the calcaneus (heel bone) and the navicular bone 
  • Talonavicular – the talus (ankle bone) and navicular are abnormally connected, this is very rare (<1%)

It is thought that 1% of the population may have a tarsal coalition and most of these are asymptomatic.

Please read about foot and ankle anatomy here, particularly the triple joint and subtalar joint.

What Can Cause It?

A genetic mutation resulting in abnormal development of the bones prior to birth is now recognised to be the underlying cause of tarsal coalitions.

During normal development, the bones in the foetus separate to form the numerous bones (over 30) that one finds in the adult foot and ankle. See foot and ankle anatomy here for more detail regarding normal anatomy.

In tarsal coalition, the natural separation does not occur and an abnormal bridge of tissue exists between the bones.

What Are The Symptoms?

The majority of people with tarsal coalitions have no or little symptoms.

Despite tarsal coalitions being present since birth in affected individuals, it is usually not until late childhood or adolescence that symptoms first begin to appear. The reason for this is that young children have very soft and flexible bones (cartilagenous). As children grow, the bones begin to ossify (calcify) which in turn stiffens the foot. At this point a fibro-cartilagenous coalition may also start to ossify turning into a stiff and solid bridge of bone between the two bones.

Ossification occurs between 8 – 12 years for calcaneonavicular and between 12 – 15 years for talocalcaneal coalitions. This is typically when symptoms first become apparent. As the affected joint stiffens, the surrounding joints have to compensate.

The subtalar joint is unique in its joint axis and motion. A tarsal coalition will stiffen the subtalar joint which will result in flattening of the foot, adpative shortening of the peroneal tendons (which can go into painful spasm) and excessive forces across the ligaments of the midfoot.

The commonest symptom patients with a tarsal coalition present with is pain, which may be due to:

  • Peroneal spasm
  • Ligament sprain
  • Sinus tarsi irritation
  • Arthritic joints 
  • Arising from the coalition

Patients may also present with:

  • Repetitive ankle sprains
  • Reduced motion and stiffness in joints particularly the subtalar joint
  • Acquired flat foot
  • Fixed flat foot
  • Difficulty walking on uneven surfaces

Patients presenting with late pain, for example in adulthood, have to be investigated for signs of arthritis.

What Investigations May Be Required?

Investigations help confirm the diagnosis, describe the tarsal coalition (fibrous, cartilagenous or bony) and where applicable, aid in pre operative planning.


Plain radiograph (x-ray)

Weight bearing lateral and oblique plain radiographs are a quick and effective way of confirming the presence of tarsal coalition. However radiographs are not completely reliable and for a definitive diagnosis a CT or MRI scan is usually obtained in addition.

Talocalcaneal coalition

On the lateral foot and ankle x-ray, your foot and ankle surgeon will be looking for evidence of the C sign and talar beaking.  Patients with arthritis may have evidence of reduced joint space particularly at the posterior aspect of the subtalar joint.

Lateral radiograph of the foot and ankle demonstrating the C sign

Lateral radiograph of the foot and ankle demonstrating the C sign

Lateral radiograph of the foot and ankle demonstrating talar beaking in a patient with subtalar coalition

Lateral radiograph of the foot and ankle demonstrating talar beaking in a patient with subtalar coalition

The Harris view is also sometimes used to assess the presence of a talocalcaneal coalition.

Harris radiographic view of the foot in a patient with talocalcaneal coalition

Harris radiographic view of the foot in a patient with partial talocalcaneal coalition

Harris radiographic view of the foot in a patient with complete talocalcaneal coalition

Harris radiographic view of the foot in a patient with complete talocalcaneal coalition

Calcaneonavicular coalition

An oblique foot and ankle x-ray will detect approximately 90% of calcaneonavicular coalitions.

Oblique radiographic view of the foot demonstrating calcaneonavicular coalition

Oblique radiographic view of the foot demonstrating calcaneonavicular coalition


MRI

MRI provides excellent high definition static images. It is useful in pre operative planning and to exclude any other pathology in the hindfoot. MRI is particularly useful when assessing the degree of fibrous and cartilage coalition as opposed to bony coalition which is best seen on CT.

MRI is particularly useful in assessing:

  • Presence of fibrous and cartilage coalition
  • Cartilage joint loss
  • Reactive bone changes
  • Effusion (fluid in the joint)
  • Synovitis (inflammation of the lining of the joint)
  • Ligament damage
  • Tendon pathology (tenosynovitis, tendon tears)
  • Any other pathology
MRI of the hindfoot revealing talar beaking

MRI of the hindfoot revealing talar beaking


CT

CT images give excellent information on bone structure and is superior to plain radiography in that respect. CT is generally accepted as the best imaging modality for tarsal coalition.

CT is particularly useful in the following cases:

  • 3D image reconstruction
  • Pre operative planning
  • Assessing adjacent joints for presence of arthritis
  • Assessing the degree/percentage coalition 
CT coronal view of both feet revealing fibrous talocalcaneal coalitions

CT coronal view of both feet revealing fibrous talocalcaneal coalitions

CT coronal view of the hindfoot demonstrating talocalcaneal coalition

CT coronal view of the hindfoot demonstrating complete bony talocalcaneal coalition


Bone Scan

Bone scan is a non specific test but is sensitive to pathology. It utilises a radioactive dye, absorbed by the body and taken up by areas of high metabolic activity such as inflammation and infection. It will not tell you what the diagnosis is, but will usually tell you if an abnormality is present.

With the easy access to CT and MRI, bone scans are rarely used. In patients who have had previous surgery and have persistent pain a bone scan may be requested.

This test is done in special circumstances.

Picture of a bone scan showing increased uptake in the foot

Picture of a bone scan showing increased uptake in the foot

Can The Problem Get Worse?

Problems can arise in two groups of patients. The young adolescent patient and the older adult population.

In the younger patient group, symptoms can limit exercise and sports and can result in deformity (flat foot). If a trial of conservative management fails then surgery may be considered.

In the older patient group, symptoms may arise form degenerative changes across the joints or as a result of an injury resulting in damage to the coalition. There is little research and literature about the outcome of tarsal coalition treatment in the adult population. As the patient has been symptomatic for many years, it is important to understand what has changed in the foot. A trial of non operative management would be recommended and surgery rarely indicated unless there is an obvious area of damage that can be treated.

Potential problems are the development of:


In summary most patients with a tarsal coalition are asymptomatic. Some patients describe stiff joints with mild ache and are able to manage their symptoms with activity modification and other non operative treatments. However some patients describe significant pain and functional limitation.

You should see an Orthopaedic Foot & Ankle Surgeon if one or more of the following applies to you:

  • Pain affecting your quality of life
  • Pain affecting your ability to work
  • Your pain is getting worse
  • You have night pain
  • You have rest pain
  • You can no longer exercise or participate in sports to the level you desire
  • You have started to develop deformity in your foot or ankle
  • You have a swelling of unknown cause
  • You are unsure about the underlying diagnosis (cause of your symptoms)
  • Failure of conservative measures such as rest, time, anti-inflammatories and physiotherapy
  • Problems with footwear

Non-Operative Treatment Options

Non operative management for tarsal coalition aims at relieving pain and return to full activity including sports whenever possible. Non operative management is more likely to be successful in patients with a talocalcaneal coalition than a calcaneonavicular coalition.

It should always be the first line of treatment. Options include:

Activity modification

A period of rest (4 to 6 weeks) from sports and exercise that bring on symptoms. Avoiding high impact activities with lots of turning and twisting.

Repetitive stress can inflame the joints and stress the bones. A period of rest can settle symptoms in the majority of cases.


Footwear modification

Wearing comfortable shoes that will help dissipate forces going through the foot. Footwear that limits hindfoot motion, will reduce the forces going through the hindfoot joint that has the coalition (and the adjacent joints) and as a result decrease symptoms.

Shoes that have a rocker bottom sole and stiff sole will also help.


Insoles & orthotics

Ankle braces give more support and stability to the ankle and subtalar joint and could ease pain particularly when doing sports and exercise.

Custom orthotics, medial arch supports, inserts like heel cups help to stabilise the foot, reduce excessive movement and forces across the joints.


Non steroidal anti-inflammatories

The use of non-steroidal anti-inflammatory drugs (NSAIDs) can decrease discomfort in patients with with inflamed joints and tendons.


Analgesics

The use of paracetamol and other painkillers to help reduce pain levels.


Physiotherapy

Physiotherapy works by strengthening muscles around not only the joint but the whole kinetic chain. Patients with tight painful peroneal muscles will benefit form stretching exercises.


Plaster cast or boot immobilisation

A short period (4 weeks) of immobilisation can reduce stresses across the joints and bones.

Injections for Tarsal Coalitions

Image guided steroid and local anaesthetic injection

This injection serves as both a therapeutic and diagnostic intervention. Steroids reduce inflammation and can ease painful symptoms. The local anaesthetic numbs an area of the body for roughly 12 to 48 hours.

The steroid is unpredictable in its success at easing painful symptoms but has very low risk of complications and therefore is an attractive therapeutic option prior to further more invasive surgical intervention. The local anaesthetic on the other hand is very predictable in its action. If there is an area of damage it will definitely ease symptoms for 12 to 48 hours. If symptoms do not ease during this period, one has to question whether the diagnosis is correct.

We carry out almost all injections under a short general anaesthetic (1 minute) as injecting into a painful joint or coalition can be quite sore. While you are asleep and lying still a small needle is inserted into the joint and the position is confirmed using an x-ray in theatre. A small amount of dye is injected first to make sure the needle is in the correct spot and then a mixture of Depomedrone (steroid) and Bupivacaine (long lasting local anaesthetic) is injected. Undertaking the injection in this manner ensures a pain free experience for the patient and the best outcome clinically as there is no doubt about the placement of the injection.

The local anaesthetic will cause numbness in the area injected for approximately 12 to 48 hours. This action is predictable. What is not predictable is the duration of action of the steroid. It may work for one month, several months or even more than a year.

Injections are not repeated less than 6 monthly intervals.

Please read here for more information regarding injections and possible complications.

Intraoperative x-ray showing correct placement of needle in the subtalar joint (confirmed with radiopaque dye)

Intraoperative x-ray showing correct placement of needle in the subtalar joint (confirmed with radiopaque dye)

Operative Treatment Options

Surgical management for tarsal coalition is reserved for patients who have failed to respond to non operative treatment.

Patients should understand that the decision to undergo surgery should not be taken lightly.

Any intervention is considered in a step wise manner, with the least invasive procedure carried out first.

Options are to either resect the coalition or fuse the joint(s).


Surgical resection

This operation involves removing the abnormal connection between the bones. It is preferable because it allows normal joint movement and often alleviates symptoms in the majority of patients. Results are better in patients who are younger and have a small coalition.

For talocalcaneal coalitions this operation is usually carried out through a small incision on the inside of the ankle. The procedure can be done as a day case procedure. Resection is recommended in patients who have a coalition less than 50% of the surface area of the joint.

For calcanealnavicular coalitions this operation is usually carried out through a small incision on the outer aspect of the foot. The procedure can be done as a day case procedure. Fat, muscle or bone wax is used to prevent bone regrowing and forming a coalition again.

A - Pre op radiograph of calcaneonavicular coalition B - Post op radiograph demonstrating complete resection of coalition

A – Pre op radiograph of calcaneonavicular coalition B – Post op radiograph demonstrating complete resection of coalition


Subtalar or triple joint fusion

For large coalitions or in the presence of arthritis and deformity in the joint(s), resection may not be a viable option. In this situation fusing the joint(s) and repositioning the bones to correct a deformity is carried out.

This operation has excellent outcomes in terms of pain relief and return to activities of daily living.

It involves removing all remnants of the diseased joint (cartilage) and fusing the affected bones. With no more joint there will be no more movement and therefore no more pain. The aim is to sacrifice painful movement for pain relief.

The majority of patients when they first hear about this procedure are quite apprehensive. This is understandable, joints exist to allow movement. A fusion is the total opposite to this, and therefore most patients perceive it as unnatural. However contrary to what most people think, after a fusion you will be less likely to limp and be a lot more active.

The operation is usually carried out through one or more small incisions on the side of the foot depending on whether a subtalar fusion or triple fusion is being carried out. The operation is undertaken under a general anaesthetic and patients usually require an overnight stay in hospital.

The main longterm complication following a subtalar or triple fusion is the development of adjacent arthritic joint disease.

The main short term complication is non union (the bones not fusing together). This is reported in numerous studies to be around 10%. In the event of this complication, the operation is repeated with bone graft to stimulate the healing and given time most patients eventually heal.

Potential Complications

It should be borne in mind that complications can result from a condition with or without surgery.


Potential complications of non-operative treatment include:

  • Worsening pain
  • Increased stiffness
  • Increasing deformity
  • Adjacent joint disease
  • Pain elsewhere, for example in the knee, hip or lower back (due to abnormal gait and compensatory mechanisms)

Complications can occur as with any type of surgery. Please see Complications for more detailed explanation of post surgical complications.

Potential general complications of any operative treatment include:

  • Risks and complications of anaesthesia
  • Bleeding
  • Infection (superficial and deep)
  • Blood clots
  • Failure to fully correct deformity (particularly if longstanding deformity)
  • Need for further surgery (revision or further treatment)
  • Persistent pain
  • Complex regional pain syndrome
  • Wound healing problems

Potential specific complications of coalition resection:

  • Incomplete resection
  • Recurrence of coalition (up to 10%)
  • Persistent pain

Potential specific complications of subtalar/triple fusion include:


Note – these complications are not exhaustive and are meant as a guide

Post Operative Period & Recovery

Please read the information regarding what to expect post surgery on this website.

Remember that below is a guide to recovery and that everyone heals at different rates and some people do take longer. Use this information to help you understand your condition, possible treatment and recovery. The timeframes given below are a minimum, it is important that you appreciate this when considering surgery as your healing and recovery may take longer.


Immediate post operative period

All surgical procedures for tarsal coalition will be carried out under a general anaesthetic.

Following tarsal coalition resection – 

You will have a backslab applied post operatively to protect the surgical sites and allow the soft tissues to heal.

A backslab after foot and ankle surgery

A picture of a backslab

Please do not remove your backslab until you are seen by your surgeon Mr Malik at the two to three week post operative clinic appointment.

You will be non weight bearing for approximately 2 to 3 weeks. The physiotherapist will guide you with the use of crutches after your operation and before your discharge from hospital.

For the first two weeks following your surgery please keep your foot elevated to the level of your heart for 95% of the time.

Plaster elevation after foot and ankle surgery

A picture demonstrating high elevation

Naturally most people do not have a hospital bed at home. The same effect can be achieved by lying in a bed or lengthways on a sofa, with pillows behind your back and under your foot. You cannot have your leg elevated sitting in a chair. It is strongly advised that during the first two weeks you are house bound.

To minimise risk of infection keep the foot dry and cool. Avoid humid and hot environments. Keep the foot dry and when showering wear a Limbo bag.

To minimise the risk of blood clots please move your foot and ankle at regular intervals. Please ensure you are well hydrated. If you have a risk of blood clots please notify Mr Malik who may organise for you to have blood thinning injections as a precaution.

In addition following a subtalar/triple fusion – 

You will spend one night in hospital after your operation and receive intravenous antibiotics the next morning. You will be in plaster for at least 6 weeks and will require to be non weight bearing for at least this period.


Two weeks post operatively

You will be reviewed at the clinic and your dressings removed. Your wound will be checked to see that it has healed and there are no signs of infection. Driving will be permitted for short trips if the left foot has been operated on and you drive an automatic. If the right foot has been operated on it will be at least 6 to 8 weeks before any driving is advisable.

Following a tarsal coalition resection – 

At this stage if your healing is progressing satisfactorily swelling and bruising should have subsided considerably, although expect some degree of swelling for at least 3 to 4 months.  If completely healed you will be given advice regarding soft tissue massage and scar desensitisation. Scar desensitisation should start as soon as the wound has completely healed. You can do this by massaging cream (E45 for example) into the scar and around the wound area. You may shower and get the area wet only if the wound has completely healed and is dry.

You will be provided with a walking boot which you should use for approximately 4 weeks.

A referral to physiotherapy will be made at this stage. This is the earliest you may return to work.

In addition following a subtalar/triple fusion – 

At this stage if the swelling has subsided sufficiently you will be advised to keep your foot in an elevated horizontal position whenever possible to minimise swelling. Your foot will be placed in another non weightbearing cast for a further 4 to 6 weeks. Short trips can be made outside, within limits of pain and swelling.


Six weeks post operatively

Following tarsal coalition resection –

Significant improvement in swelling and pain. You will be able to start wearing normal footwear (swelling permitted), although stiff soled shoes are advisable. You will require physiotherapy for approximately 3-6 months. This will help optimise the outcome of your operation.

In addition following a subtalar/triple fusion – 

At this stage if your healing is progressing satisfactorily swelling and bruising should have subsided considerably, although expect some degree of swelling for at least 4 to 6 months.

Depending on the x-ray findings you will either go into a walker boot and be allowed to weight bear through the operated foot, or you will have to remain non weight bearing in plaster.

If your x-rays are encouraging and your wounds completely healed you will be given advice regarding soft tissue massage and scar desensitisation. Scar desensitisation should start as soon as the wound has completely healed. You can do this by massaging cream (E45 for example) into the scar and around the wound area. You may shower and get the area wet only if the wound has completely healed and is dry.


Three months post operatively

Following a tarsal coalition resection – 

Final clinical examination. Discharge if satisfactory.

Following a subtalar/triple fusion

Check radiographs should show signs of bone healing. You will be able to start wearing normal footwear (swelling permitted), although stiff soled shoes are advisable. You will require physiotherapy for approximately 3-6 months. This will help optimise the outcome of your operation.

FAQs

How long does the operation take?

This is probably the most common question asked of surgeons. Total operation time is different from the actual total surgical time. For example a flight involves not just the flying time, but the time checking in, going through security and boarding the plane for example.

The time given below is only a guide to the actual surgical time.

For talocalcaneal coalition resection – 

Up to 60 minutes.

For calcaneonavicular coalition resection – 

Up to 60 minutes.

For a subtalar/triple fusion – 

90 to 120 minutes.


When can I drive?

For tarsal coalition resection –

Most patients are able to drive after 6 to 8 weeks. Please see guidance below.

For a subtalar/triple fusion – 

Not for at least 3 months post surgery.

Please see guidance above and information here. Ultimately it is the responsibility of the patient to decide if they are safe to drive. A good way of knowing is if you can stamp your right foot heavily on the ground to mimic an emergency brake. If you have any hesitation or pain then it should suggest you are not safe to drive. Remember prolonged driving involves keeping your feet in a dependant position. This will worsen the post operative swelling.


When can I return to work?

For tarsal coalition resection –

Most patients are able to return to work within 14 to 28 days taking into consideration they are in a walking boot.

For a subtalar/triple fusion – 

This really depends on you and your job. If you have a job that involves a lot of standing, walking and is manual it may be 8 to 12 weeks. If you have a sedentary job, for example in an office and you have a reasonable commute you may be able to go back to work at 2 weeks, although this would be exceptional and not the norm.


What should the final outcome be?

Following a tarsal coalition resection –

Excellent pain relief and return to sports by 6 months. Failure of this outcome warrants further investigation and possible treatment.

For a subtalar/triple fusion – 

Excellent pain relief and return to full activities of daily living.

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