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Tarsal coalitions develop due to failure of mesenchymal separation of tarsal bones.
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Most commonly coalitions are calcaneonavicular or talocalcaneal.
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Subtalar stiffness results in pathologic kinematics with increased risk of ankle sprains, most often planovalgus foot deformity and progressive joint degeneration.
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Resection of the coalition yields good results; tissue interposition may reduce the risk of reossification, and concomitant deformity should be addressed.
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The primary trigger to joint fusion
Coalitions of the Tarsal Bones
Section snippets
Key points
Historical perspective and incidence
The entire historical perspective is summarized in Table 1. Clinical series estimate the incidence of tarsal coalitions about 1% to 6%; however, because they are often asymptomatic or undiagnosed the real incidence certainly might be higher.2, 4, 5, 6, 7 Better accuracy may be obtained using cadaver series reporting rates of 12.7% to 13% in series of more than 100 dissected specimen.8, 9 MRI series on 574 consecutive patients revealed a similar rate of 11.5%.5
The most common found type is the
Cause
Most coalitions are congenital. Leboucq in 1890 was the first to propose a failure of segmentation of primitive mesenchyme.24 This is generally accepted since Harris found mesenchymal coalitions in fetal cadavers. However, today an autosomal dominant inherited pattern with a high penetrance is assumed.11, 13, 25 Of patients with symptomatic tarsal coalitions, Leonard found asymptomatic coalitions in 39% of all and 76% of first-degree relatives. Coalition may be associated with other congenital
Pathophysiology
During the swing phase of gait the subtalar joint complex is positioned in a flexible valgus to accommodate for ground contact. During stance phase it changes into a rigid varus to allow effective translation of muscle force into body motion. External tibia rotation is compensated by subtalar internal rotation. If the coalition locks the subtalar joint motion, the gliding of the navicular and cuboid at the end of dorsiflexion is stopped and as a consequence the midtarsal joints need to
Clinical presentation
In adolescents who complain about foot pain tarsal coalition should always be kept in mind.34 Timing of onset of symptoms is thought to correspond with the time of ossification and increasing stiffness of the foot.10, 35, 36 In calcaneonavicular coalitions this typically occurs at age 8 to 12 years, whereas in talocalcaneal coalitions they ossify later (12–16 years).37 Diffuse pain that exacerbates during activity is the main symptom and can be triggered by a minor trauma.38 As a consequence
Imaging
In 1921 Slomann was first to describe the identification of a calcaneonavicular coalition on plain radiograph.44 For calcaneonavicular coalitions the 45° oblique view has a sensitivity of 90% to 100%. Talocalcaneal coalitions are more likely to be missed due to superimposed bony structures and their oblique orientation.44, 45 Fibrocartilaginous coalitions are identified by a decreased bony gap bordered by irregular sclerotic margins. Standard examination consists of weight-bearing ankle
Natural history
The fact that most coalitions remain asymptomatic through entire life is reflected by the difference between the incidences of clinical and cadaver or advanced imaging studies. Calcaneonavicular coalitions are less likely to progress into secondary joint degeneration and assumable because subtalar motion is less restricted.9
Conservative treatment
The first-line treatment consists of nonoperative treatment strategies. Activity modifications, antiinflammatory measures including nonsteroidal antirheumatics or corticoid injections and functional orthotics can be applied.56 Physical therapy is used to address any peroneal and calf muscle tightness.30 If pain relief is insufficient cast immobilization in a neutral position for 3 to 6 weeks can be offered. After cast removal 30% of patients may remain pain free but the response rate is worse
Resection of Calcaneonavicular Coalition
Failed conservative treatment may warrant surgical treatment.
The patient is positioned supine or in the lateral decubitus position. The investigators prefer Ollier approach over the sinus tarsi. Once the inferior extensor retinaculum is divided the surgeon advances to the coalition reflecting the muscle belly of the short toe extensor from its insertion on the calcaneus. Preventing to open the talonavicular joint capsule protects its cartilage and later subluxation. A bone block of at least
Joint fusion in tarsal coalition
In case of multiple coalitions, failed primary resection and/or joint degeneration fusion is considered (Fig. 5). Fuson and colleagues38 found that the level of pain was the determining factor to decide for joint fusion. Therefore, resection of coalitions should not be confined to adolescent patients. Good results have been shown not to depend on age as long as no joint degeneration has occurred.63, 98 The talar beak is caused by traction of the capsule and should not be misinterpreted as
Summary
Tarsal coalitions are the result of impaired mesenchymal separation of the tarsal bones. The most common types include calcaneonavicular or talocalcaneal coalitions. They usually get first time symptomatic because of an ankle sprain. Subtalar stiffness results in pathologic kinematics with increased risk of ankle sprains, planovalgus foot deformity, and progressive joint degeneration.
Resection of the coalition yields good results. Tissue interposition may reduce the risk of reossification, and
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Cited by (29)
Tarsal coalitions: Focusing on calcaneonavicular and talocalcaneal coalitions
2023, Fuss und SprunggelenkAn update on tarsal coalitions
2023, Orthopaedics and Trauma[Translated article] Tarsal coalitions as a cause of pain in the foot of children: Therapeutic options
2022, Revista Espanola de Cirugia Ortopedica y TraumatologiaLateral Arthroscopic Subtalar Arthrodesis for Talocalcaneal Coalition: Surgical Technique
2022, Arthroscopy Techniques
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