Q66.89 Other specified congenital deformities of feet
Tarsal Coalition ICD-9
755.67 (Anomalies of foot, NEC) tarsal coalitions, talonavicular synostosis, coalition of calcaneous, calcaneonavicular bar, astrgaloscaphoid synostosis)
Tarsal Coalition Etiology / Epidemiology / Natural History
Congenital anomaly with the union of 2 or more tarsal bones causing decreased or absent motion.
can be a cartilaginous, fibrous, or bony union most often seen in the hindfoot and less commonly in the midfoot.
typically teenager with increasingly midfoot pain, insidious onset, activity related, and relieved by rest. Stiffness of foot, hx of ankle sprains.
Disorder of mesenchymal segmantation. May be inherited in an autosomal dominant pattern. (Leonard MA: JBJS 1974;56Br:520-526)
Occurs in @1% of US population
talocalcaneal, calcaneonavicular most common. Rare=talonavicular, calcaneocuboid, cubitonavicular, and naviculocuneiform joints.
leading cause of peroneal spastic flatfoot
Tarsal Coalition Anatomy
Tarsal Coalition Clinical Evaluation
history of repeated ankle sprains or vague, nonspecific symptoms in the hindfoot or midfoot following minor trauma.
c/o calf pain due to peroneal spasticity, flatfoot, limited subtalar motion,
Typically teenagers, age 10-12
restriction of hindfoot inversion and eversion, full ROM of ankle
Tarsal Coalition Xray / Diagnositc Tests
plain radiographs often normal, best evaluated with CT scan(Herzenberg, Foot Ankle 1986;6:273-288)
C-sign on lateral x-ray is highly sensitive and specific for TCC. C-sign = a C-shaped line formed by the medial outline of the dome of the talus and the posteroinferior outline of the sustentaculum tali. (Sakellariou A et al: Talocalcaneal coalition: Diagnosis with the C sign on lateral radiographs of the ankle. JBJS Br 2000;82:574-578)
Other x-ray findings include a talar beak, narrowing of the posterior subtalar joint space, failure to visualize the middle subtalar joint, and loss of height of the longitudinal arch.
CT: indicated before surgical treatment to ipsilateral coalitions, ie concommitant calcaneonavicular and subtalar coalitions.
Tarsal Coalition Classification / Treatment
conservative=heel cup with medial-wedge or longitudinal arch support. Short leg walking cast with slight varus mold for 2-4weeks followed by UCBL orthosis.
Calcaneonavicular or talocalcaneal coalition=WBSLC for 2-4wks followed by UCBL orthosis. Consider resection of the coalition and interposition of autogenous fat graft, or extensor digitorum brevis muscle if non-op treatment fails (Gonzalez P, JBJS 1990;72A:71).
Consider primary triple arthrodesis in patients with degenerative changes in the subtalar or midfoot joints.