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Tarsal Coalition

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Other Names

  • Talocalcaneal coalition
  • Calcaneonavicular coalition
  • Peroneal spastic flatfoot


  • This page refers to abnormal connections of the tarsal bones, commonly referred to as 'tarsal coalition'


  • First described by Buffon in 1750 or 1769 (need citation)
  • In 1948, Harris and Beath were the first to identify tarsal coalition as a cause of painful and rigid pes planovalgus[1]


  • Prevalence
    • Estimated to be between 1% and 13% of the population[2]
    • Likely under-reported due to vast majority being asymptomatic
    • Appear bilaterally in 50% - 68% of all cases, 20% have multiple coalitions[3]
    • Solomon found a prevalence of non-osseous coalition to be 12.75 in a cadaveric study[4]


  • General
    • Definition: abnormal osseous, cartilaginous or fibrous connection between two or more tarsal bones
    • Due to a failure of differentiation and segmentation of primitive mesenchyme into the distinct tarsal bones
    • The coalition can be bony (synostosis), cartilaginous (synchondrosis), or fibrous (syndesmosis)
    • May involve fusion of the accessory ossicles[5]
    • It is an often unrecognised cause of foot and ankle pain
  • Natural history
    • Majority are cartilaginous at birth and are therefore asymptomatic
    • Evidence suggests coalitions remain asymptomatic into adulthood[6]
    • When symptoms arise, thought to be a result of microfractures of the coalition and inflammation of the surrounding soft tissue from repetitive overload[7]
    • Age of presentation varies, depending on which bones are involved
    • Appears to be approximately 3--4 years after ossification of the coalition


  • General
    • Talocalcaneal and calcaneonavicular coalitions are its most common subtypes, represent about 90% of junctions[3]
  • Talocancaneal
    • Most common, affecting 48% of the patients[3]
    • Commonly concerns the middle subtalar facet[8]
    • Rarely involves he anterior and posterior facets
  • Calcaneonavicular
    • Other investigators have reported a nearly equal prevalence of talocalcaneal and calcaneonavicular coalitions[9]
    • More readily diagnosed with conventional radiography, which may contribute to their reported higher prevalence
  • Talonavicular
  • Calcaneocuboid
  • Naviculocuneiform
  • Cubonavicular


  • Thought to be due to a failure of segmentation of primitive mesenchyme during development[10]
  • Genetics
    • There may be an autosomal dominant pattern of inheritance of a coalition[11]
    • Pro250Arg mutation in the fibroblast growth factor receptor 3 (FGFR3) gene has been associated[12]
  • Acquired
    • May occur due to may occur because of degenerative joint diseases
    • Examples: inflammatory arthritis, fibular hemimelia, congenital talipes equinovarus, Apert syndrome, arthrogryposis, and Nievergelt--Pearlman syndrome

Associated Conditions

  • Pes Planus
  • Other congenital malformations
    • Including carpal fusions, carpal synostosis with radial head subluxation, symphalangism, and partial adactyly
  • Ankle Sprain


Risk Factors

  • Slight male predominance[13]
  • Race

Differential Diagnosis

Clinical Features

  • History
    • Symptoms initiate with the onset of ossification, calcaneonavicular (8-12 years), talocalcaneal (8-12 years), talonavicular (3-5 years)[15]
    • Mid-, hindfoot or tarsal pain, sometimes diffuse
    • Trouble walking on uneven surfaces
    • If there is a precipitating event, trauma, weight gain, or an increase in athletic activity
    • Pain is diffuse, exacerbates during physical activity, and may be triggered by minimal trauma[16]
    • Progressing to decreased range of motion, especially inversion/eversion of the subtalar joint
    • Rigid deformity is usually the end point
  • Physical Exam: Physical Exam Foot
    • Rigid pes planus, hindfoot valgus
    • Inability to roll onto lateral side of foot (secondary to rigid pes planus)
    • Tightness of peroneal muscles, long extensors which may be obvious dorsally
    • "Double medial malleolus" with talocalcaneal coalition[17]
    • Ankle range of motion is normal while subtalar range of motion is restricted
  • Special Tests



  • Standard Radiographs Foot, Standard Radiographs Ankle
    • Initial imaging modality of choice
    • Views should include anteroposterior, lateral, oblique, and axial weight-bearing
  • Harris axial view (Harris-Beath)
    • Sometimes termed Harris projection or penetrated axial projection
    • Special radiographic view that is used for assessment of talocalcaneal coalition
    • X-ray beam is angled between 35 and 45 degrees
  • Calcaneonavicular coalitions
    • Best visualized on internal oblique 45° view
    • Coalition is seen in 90% of cases[18]
    • 'Anteater nose' sign is a characteristic finding
      • Initially described in the oblique view, better visualized on lateral view
      • Sensitivity 18-50%, specificity 100%[19][20]
  • Talocalcaneal coalitions
    • 'C' sign
      • C-shaped line composed of the medial dome of the talus and posteroinferior outline of the sustentaculum tali
      • Seen in lateral views, specific but not sensitive[21][22]
    • Absent middle facet may be a more accurate radiographic finding[23]
    • Dorsolateral talar beak
      • Thought to occur due to impaired subtalar joint motion, subsequently the navicular overrides the talus.
      • Periosteal elevation occurs at the insertion of the talonavicular ligament, a cycle of osseous leads to formation[24]
      • Alternatively, may occur due to peroneal spasm with repetitive dorsolateral overload, compression of the talar head
      • Note: may occur absent a tarsal coalition


  • More sensitive, more specific than xray
  • Also assesses for soft tissue injuries, bone edema


  • Similar utility for osseous connections, but less for fibrous
  • offers a more precise evaluation of the site and size of coalition
  • Help determine determine surgical approach, i.e. resection, arthrodesis
  • Can exclude multiple coalitions and readily depicts associated degenerative changes[25]


Downey Classification

  • Considers joint involvement, arthrosis extension to help in recommending surgical therapy[26]
    • Type IA: extra-articular coalition without secondary arthritis
    • Type IB: intra-articular coalition with secondary arthritis
    • Type IIA: extra-articular coalition without secondary arthritis
    • Type IIB: intra-articular coalition with secondary arthritis

Rozansky Classification

  • Based on three-dimensional reconstructed computed tomography images[27]
    • Type I: linear coalitions (41%)
    • Type II: linear coalitions with posterior hook (17%)
    • Type III: shingled coalitions (15%)
    • Type IV: complete osseous coalitions (11%)
    • Type V: posterior coalitions (17%)



  • Indications
    • Asymptomatic or incidentally discovered lesions
    • Most symptomatic lesions upon initial presentation
  • Initial therapy
    • NSAIDS
    • Shoe inserts
    • Activity modification
  • If symptoms persist, consider
    • Custom orthotics
    • Cast immobilization


  • Indications
    • Failure of conservative management
  • Objective
    • Achieve painless functional hindfoot movement without deformity
  • Technique
    • Subtalar or triple arthrodesis
    • Excision of coalition with or without interposition of fat or tendon

Rehab and Return to Play


  • Needs to be updated

Return to Play/ Work

  • Needs to be updated

Complications and Prognosis


  • Incidental or asymptomatic lesions
    • No evidence suggesting that asymptomatic coalition may lead to future problems[21]
  • Conservative vs surgical management
    • Calcaneonavicular coalitions respond less to conservative treatment than talocalcaneal coalitions[28]
  • Surgical outcomes
    • Mahan et al observed 73% of patients achieved good results, regardless of the type of coalition[29]
    • Khoshbin et al reevaluated patients after resection of calcaneonavicular and talocalcaneal coalitions, found that 85% of the patients did not require additional procedures[30]
    • Mosca showed 87% of patients achieved good results after talocalcaneal coalition resection[31]
  • Predictors of good outcome with conservative management (need citation)
    • Skeletal immaturity at presentation
    • Nonathletic patient
    • Ankylosed subtalar joint in neutral


See Also


  1. Harris RI, Beath T. Etiology of peroneal spastic flat foot. J Bone Joint Surg Br 1948; 30B:624–634.
  2. Bohne WH. Tarsal coalition. Curr Opin Pediatr 2001; 13:29–35.
  3. 3.0 3.1 3.2 Stormont DM, Peterson HA. The relative incidence of tarsal coalition. Clin Orthop 1983; (181):28–36.
  4. Solomon LB, Rühli FJ, Taylor J, et al. A dissection and computer tomograph study of tarsal coalitions in 100 cadaver feet. J Orthop Res. 2003;21:352–358
  5. Mosier KM, Asher M. Tarsal coalitions and peroneal spastic flat foot: a review. J Bone Joint Surg. 1984;66-A:976–984
  6. Conway JJ, Cowell HR. Tarsal coalition: clinical significance and roentgenographic demonstration. Radiology. 1969; 92:799--811.
  7. Kumai T, Takakura Y, Akiyama K, et al. Histopathological study of nonosseous tarsal coalition. Foot Ankle Int. 1998; 19:525--531.
  8. Moe DC, Choi JJ, Davis KW. Posterior subtalar facet coalition with calcaneal stress fracture. AJR Am J Roentgenol. 2006;186(1):259–64.
  9. Kulik SA, Clanton TO. Tarsal coalition. Foot Ankle Int. 1996;17:286–296
  10. Vincent KA. Tarsal coalition and painful flatfoot. J Am Acad Orthop Surg. 1998;6:274–281
  11. Leonard MA. The inheritance of tarsal coalition and its relationship to spastic flat foot. J Bone Joint Surg Br 1974; 56B:520–526.
  12. Graham JM, Braddock SR, Mortier GR, et al. Syndrome of coronal craniosynostosis with brachydactyly and carpal/tarsal coalition due to Pro250Arg mutation in FGFR3 gene. Am J Med Genet 1998; 77:322–329.
  13. Swensen SJ, Otsuka NY. Tarsal coalitions–calcaneonavicular coalitions. Foot Ankle Clin 2015; 20:669–679.
  14. Burnett SE, Wilczak CA. Tarsal and tarsometatarsal coalitions from Mound C (Ocmulgee Macon Plateau site, Georgia): implications for understanding the patterns, origins, and antiquity of pedal coalitions in Native American populations. Homo Int Z Vgl Forsch Am Menschen 2012; 63:167–181.
  15. Cowell HR. Tarsal coalition–review and update. Instr Course Lect 1982; 31:264–271.
  16. Fuson S, Barrett M. Resectional arthroplasty: treatment for calcaneonavicular coalition. J Foot Ankle Surg 1998; 37:11–15.
  17. Rocchi V, Huang M-T, Bomar JD, Mubarak S. The ‘double medial malleolus’: a new physical finding in talocalcaneal coalition. J Pediatr Orthop 2018; 38:239–243.
  18. Newman JS, Newberg AH. Congenital tarsal coalition: multimodality evaluation with emphasis on CT and MR imaging. Radiographics 2000; 20:321–332.
  19. Kernbach KJ. Tarsal coalitions: etiology, diagnosis, imaging, and stigmata. Clin Podiatr Med Surg 2010; 27:105–117.
  20. Crim JR, Kjeldsberg KM. Radiographic diagnosis of tarsal coalition. AJR Am J Roentgenol 2004; 182:323–328.
  21. 21.0 21.1 Taniguchi A, Tanaka Y, Kadono K, et al. C sign for diagnosis of talocalcaneal coalition. Radiology 2003; 228:501–505.
  22. Brown RR, Rosenberg ZS, Thornhill BA. The C sign: more specific for flatfoot deformity than subtalar coalition. Skeletal Radiol. 2001; 30:84--87.
  23. Liu PT, Roberts CC, Chivers FS, et al. ‘Absent middle facet’: a sign on unenhanced radiography of subtalar joint coalition. AJR Am J Roentgenol 2003; 181:1565–1572.
  24. Resnick D. Talar ridges, osteophytes, and beaks: a radiologic commentary. Radiology. 1984; 151:329--332.
  25. Wechsler RJ, Schweitzer ME, Deely DM, et al. Tarsal coalition: depiction and characterization with CT and MR imaging. Radiology. 1994; 193:447--452.
  26. Downey MS. Tarsal coalitions. A surgical classification. J Am Podiatr Med Assoc 1991; 81:187–197.
  27. Rozansky A, Varley E, Moor M, et al. A radiologic classification of talocalcaneal coalitions based on 3D reconstruction. J Child Orthop 2010; 4:129–135.
  28. Klammer G, Espinosa N, Iselin LD. Coalitions of the tarsal bones. Foot Ankle Clin 2018; 23:435–449.
  29. Mahan ST, Spencer SA, Vezeridis PS, Kasser JR. Patient-reported outcomes of tarsal coalitions treated with surgical excision. J Pediatr Orthop 2015; 35:583–588.
  30. Khoshbin A, Bouchard M, Wasserstein D, et al. Reoperations after tarsal coalition resection: a population-based study. J Foot Ankle Surg 2015; 54:306–310.
  31. Mosca VS. Subtalar coalition in pediatrics. Foot Ankle Clin 2015; 20:265–281.
Created by:
John Kiel on 15 November 2021 19:14:44
Last edited:
4 October 2022 12:37:14