What Is Tarsal Coalition

  • Eva Henning MSc Precision Medicine, University of Manchester, UK
  • Helen McLachlan MSc Molecular Biology & Pathology of Viruses, Imperial College London

Background

Tarsal coalition is a condition that occurs when two or more tarsal bones in the back of the foot are fused together. The anatomical term coalition means the abnormal connection of two bones.10 Consequently, there is no arch to the foot, resulting in a flat appearance. Statistics show its rarity with one in one hundred people being estimated as having the condition.12 Those with a tarsal coalition are born having two bones connected. The associated fusion site most commonly occurs between the calcaneus and navicular bones which are located in the midfoot and only in half of the cases are both feet affected. 

Anatomy of the foot

The foot can be partitioned into three sections: the forefoot, midfoot and hindfoot. These three foot sections are secured via the presence of ligaments such as the talonavicular and deltoid ligaments which connect to the talus.13 The hind foot is located at the back of the foot towards the ankle, and contains two tarsal bones; talus and calcaneus. The hind foot is involved in rotations of the ankle alongside absorbing weight load.13 Therefore, the function of the hindfoot allows for quickly accessible foot movements as it interacts with the ankle joint. It also absorbs the weight load whilst standing by spreading the weight amongst the hindfoot region. The midfoot, accounts for the arch region of the foot and consists of several bones including the navicular, cuneiforms and cuboid bones.8 The function of the midfoot is to absorb and disperse force on engagement with the ground. The presence of the arch in the midfoot acts as an external stabiliser.8 The forefoot is directly in contact with the toe bones which have a central role in providing balance amongst the feet. Each foot contains five metatarsal bones numbered one to five which link the toes directly to the midfoot region.9 These three compartments each have functional roles in providing overarching support and stability to the human body and so are vital in coordination. It is the hindfoot and midfoot which are composed of tarsal bones which are involved in tarsal coalitions. 

Image of a tarsal coalition14 (Masci L., 2022)

Subcategories of tarsal coalitions

  • Talocalcaneal coalition – talus and calcaneus bone fusion
  • Calcaneonavicular coalition – calcaneus and navicular bone fusion
  • Talonavicular coalition – talus bone and navicular bone fusion

The most prevalent bone fusion is the calcaneonavicular coalition.7 Each of these subtypes of tarsal coalitions has abnormalities which result in specific regional bone fusions that lead to restriction in the movement of the affected feet. The limited range of foot movement can cause discomfort when walking as the foot may be less flexible. It may interfere with daily activities, and so often requires medical attention to address the issue. 

Am I at risk of a tarsal coalition?

The cause of a tarsal coalition is most often due to a genetic alteration in a gene that causes abnormal development of the foot bones from birth. This results in the inability to separate the primary mesenchymal cells during growth.7 Therefore, diagnosis of the condition often occurs in much later years of adolescence when it begins to interrupt daily activities (The Children's Hospital of Philadelphia, 2017). However, in some cases, the condition can be a result of injury or infection. 

Signs and symptoms 

Most patients who have a tarsal coalition may be unaware due to the lack of symptoms that present. This is because tarsal coalitions present with non-traumatic pain.5 Studies have noted that pain associated with tarsal coalition tends to occur much later in life.1 Therefore the number of cases of tarsal coalitions is anticipated to be greater.7 Symptoms tend to vary depending on the case severity. The most common symptoms that present among cases include:

  • Presentation of a flat foot
  • Stiffness
  • Limited ankle rotation
  • Foot pain during physical activity 
  • Ankle sprains
  • Abnormal gait

As symptoms can often present with as little as foot discomfort, the severity of the case must be considered. Some individuals may present with severe pain that disrupts their quality of life due to having restricted foot movement so medical attention is required. Often examination by an orthopaedic allows for the diagnosis of a tarsal coalition alongside the available treatment options.

Diagnosis criteria 

A comprehensive overview including physical and clinical evaluation alongside patient medical history is considered. For example, an orthopaedic doctor will discuss relevant symptoms alongside assessing family history. This is often followed by a physical examination of the foot to check for tenderness or range of motion in ankle rotation. As abnormal gaits are often a symptom of tarsal coalition this will also be assessed.3 Diagnosis in most cases can be confirmed on physical examination and imaging, however this can be complex.4 CT scans can provide insight into associated anatomical abnormalities alongside determining the severity of the tarsal coalition, as it can provide a detailed image of the affected region which helps confirm diagnosis. Sometimes, bone scintigraphy is required to examine the location and regulation of blood flow surrounding the coalition in complex cases.6

Treatment protocol

Non-surgical approaches remain the first line of action in the treatment of a tarsal coalition in cases where pain is not significant. For example, conservative management involves avoiding physical exercise that strains or puts pressure on the tarsal coalition. For improved overall foot flexibility, nonsteroidal anti-inflammatory medications (NSAIDs) and physical foot therapy can also be administered. Other forms of management include the application of orthotic devices to assist foot support to the strained area or casting of the foot to immobilise the foot and enable a resting period.11 When these options are not effectively resolving the pain, surgical resection remains an option. This includes the removal of the tarsal coalition, the area of the connected bone by surgery, followed by replacing the region with surrounding muscle tissue or fat.11 Replacing the region with fat is associated with a reduced recurrence rate as an efficient region filler.3 A benefit of surgical operation is that it allows for individuals to have a range of movement in the foot. According to surgical reports, athletes with tarsal coalitions who received resection returned to their preoperative sports levels after surgery.11 These treatment options are often case-dependent and are based on a range of factors including age, activity rate and the region of the tarsal coalition. The risk of complications following the surgical procedure remains relatively low however must be considered.2 In some cases, treatment may fail and patients may still be in pain so a joint fusion surgery is suggested.11 Surgery usually needs to be followed by rehabilitation, as patients will need to regain foot mobility and strength.

Prognosis and long-term outlook

A patient's long-term outlook for a tarsal coalition often depends on the type of treatment used and the patient's response to that treatment. If a tarsal coalition is identified and treated in its early stages, physical therapy can help relieve strain. In these cases, the long-term outlook for recovery remains positive as the level of discomfort does not greatly impact the quality of life. In more severe cases, where there is surgical intervention the importance of postoperative care remains essential in assisting rehabilitation.2 This can lead to an improved long-term outlook to facilitate full movement of the foot. Individuals of younger age may recover much more quickly – within approximately 3 weeks post surgery and regain more strength.3 Long-term adjustments to aid foot movement must be considered in some patients such as a supporting foot sole or avoiding strenuous activity to prevent bone stresses. Longer-term outlook includes regular checkups to monitor the tarsal coalition and prevent further issues. 

Prevention and lifestyle considerations

General lifestyle considerations such as actively exercising to maintain a healthy weight alongside eating a balanced diet can limit the complications associated with the syndrome. However, strenuous exercise that may further impede a tarsal coalition should be avoided as this may place further strain on the bones. You should therefore seek medical advice on the type of exercise that is appropriate for you. Another important consideration is wearing appropriate footwear that actively supports the arches of the feet. For example cushioned shoes and arch support can help prevent a flat foot and pressure on arches. Regular feet checkup if you have been diagnosed with a tarsal coalition to ensure the condition does not worsen. It is important to consider that unfortunately tarsal coalitions is not a condition that can be avoided due to the embryo genetic development.1 Therefore preventative measures are of less importance and management is critical to minimise the impact on your everyday life. 

Summary

In summary, many individuals who have a tarsal coalition can live a pain-free and regular life. This is often due to early diagnosis and management of the condition to prevent further abnormalities of the foot. For the best possible outcome, long-term management of the tarsal coalition should be considered as advised by a clinician. Treatment of tarsal coalitions can provide a positive long-term outlook if appropriate and efficient treatment is provided based on the subtype of coalition present. By being aware of the symptoms associated with tarsal coalitions, you can seek medical advice as soon as possible.

References

  • Docquier, P.-L., Maldaque, P. and Bouchard, M. (2019) ‘Tarsal coalition in paediatric patients’, Orthopaedics & Traumatology: Surgery & Research, 105(1). doi:10.1016/j.otsr.2018.01.019. 
  • Hollander, J.J. et al. (2022) ‘8 out of 10 patients do well after surgery for tarsal coalitions: A systematic review on 1284 coalitions’, Foot and Ankle Surgery, 28(7), pp. 1110–1119. doi:10.1016/j.fas.2022.03.011. 
  • Kothari, A. and Masquijo, J. (2020) ‘Surgical treatment of tarsal coalitions in children and adolescents’, EFORT Open Reviews, 5(2), pp. 80–89. doi:10.1302/2058-5241.5.180106. Z
  • Lawrence, D.A. et al. (2014) ‘Tarsal coalitions: Radiographic, CT, and mr imaging findings’, HSS Journal ®, 10(2), pp. 153–166. doi:10.1007/s11420-013-9379-z. 
  • Lim, S. et al. (2013a) ‘A Radiological Classification system for talocalcaneal coalition based on a multi-planar imaging study using CT and MRI’, Insights into Imaging, 4(5), pp. 563–567. doi:10.1007/s13244-013-0267-3. 
  • Deutsch, A.L., Resnick, D. and Campbell, G. (1982) ‘Computed tomography and bone scintigraphy in the evaluation of Tarsal coalition.’, Radiology, 144(1), pp. 137–140. doi:10.1148/radiology.144.1.6211690. 
  • Park, J.J. et al. (2022) ‘Racial differences in prevalence and anatomical distribution of Tarsal coalition’, Scientific Reports, 12(1). doi:10.1038/s41598-022-26049-6. 
  • Fraser, J. J., Feger, M. A., & Hertel, J. (2016). MIDFOOT AND FOREFOOT INVOLVEMENT IN LATERAL ANKLE SPRAINS AND CHRONIC ANKLE INSTABILITY. PART 1: ANATOMY AND BIOMECHANICS. International journal of sports physical therapy, 11(6), 992–1005.
  • Lezak, B. and Massel, D.H. (2023) Anatomy, bony pelvis and lower limb: Metatarsal bones, Anatomy, Bony Pelvis and Lower Limb: Metatarsal Bones. Available at: https://www.ncbi.nlm.nih.gov/books/NBK549872/ 
  • Glaser, C. (2016) ‘Tarsal coalitions: A practical approach to a not-so-rare entity’, Journal of the Belgian Society of Radiology, 100(1). doi:10.5334/jbr-btr.1224. 
  • Saxena, A. et al. (2022) ‘Tarsal coalition resections: A long-term retrospective analysis of 97 resections in 78 patients’, Journal of Orthopaedic Surgery and Research, 17(1). doi:10.1186/s13018-022-03350-8. 
  • Kulik SA, Clanton TO. Tarsal Coalition. Foot & Ankle International. 1996;17(5):286-296. doi:10.1177/107110079601700509
  • Ghanem, I. et al. (2019) ‘Understanding the foot’s functional anatomy in physiological and pathological conditions: The Calcaneopedal Unit Concept’, Journal of Children’s Orthopaedics, 13(2), pp. 134–146. doi:10.1302/1863-2548.13.180022. 
  • Masci, L. (2022) Tarsal coalition: A cause of ankle pain - sport doctor london, Tarsal coalition: a cause of ankle pain. Available at: https://sportdoctorlondon.com/tarsal-coalition/ 
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Eva Henning

MSc Precision Medicine, University of Manchester, UK

Eva Henning is an enthusiastic intern with a strong academic background in science communication. Holding a Bachelor of Sciences from the University of Manchester, Eva continues her scientific journey by pursuing a Masters in Precision Medicine. Having gained experience in medical sciences, Eva brings a unique blend of academics and a passion for effective science communication with the general public. Eva provides readers with accurate, insightful and engaging content on a range of medical health content.

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