Case. 15 Y old boy presented with pain in the foot. No history of injury or any constitutional symptoms. Your diagnosis?

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Marilynn Hancock
5 years ago
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1 Case 15 Y old boy presented with pain in the foot. No history of injury or any constitutional symptoms Your diagnosis?

Diagnosis: Calcaneo-navicular tarsal coalition.

Coalitions occur most commonly in 1% to 2% of the population.

Coalitions are also classified based on the type of intervening tissue and include osseous, cartilaginous, or fibrous types.

2 Diagnosis: Calcaneo-navicular tarsal coalition. C sign Talar beaking Ant eaters nose A coalition is a congenital bridge or bar between adjacent tarsal bones. Coalitions occur most commonly in 1% to 2% of the population. 90% of tarsal coalitions involve the talocalcaneal and calcaneonavicular joints. Coalitions are also classified based on the type of intervening tissue and include osseous, cartilaginous, or fibrous types. It is bilateral in 70% An autosomal dominant inheritance pattern with variable penetrance. Most often presents in adolescence, with insidious or acute onset of midfoot or hindfoot pain. Talocalcaneal coalition is difficult to visualize on standard views of the foot, secondary to the anatomic complexity of this joint. May need CT or magnetic resonance imaging (MRI) to evaluate the location and type of coalition.

3 The mesenchymal anlage fails to complete its normal separation, resulting in the lack of normal tarsal joint formation. Subtalar fusion almost invariably involves the middle facet between the talus and the sustentaculum tali. CLINICAL FINDINGS Is asymptomatic in early childhood. Usually pain starts between 12 and 16 years, with heavy or more active patients. The coalition bar prevents normal subtalar joint motion. Cause: peroneal spastic flatfoot. Often found a rigid flatfoot with decreased hindfoot motion, pes planus, and calcaneus valgus. Talo-calcaneal coalition, the bar ossifies in years Calcaneo-navicular coalition, the bar ossifies in 8-12 years DIAGNOSTIC IMAGING 1. X rays Harris or axial calcaneal view of the foot. 1. Narrowing of the subtalar joint, overgrowth of the lateral process of the talus, 2. Failure of visualization of the middle subtalar joint, the C sign [TC bar] 3. Talar beak in Talocalcaneal bar 4. Ball and socket configuration of the ankle joint. 5. Ant Eater s sign in Talo-navicular coaliton 2. CT Computed tomography and MRI provide similar anatomic coalition delineation. In osseous fusion, a bony bridge is identified between the talus and the sustentaculum at the middle facet.

3. MRI MRI can contribute additional information about marrow edema-like signal changes and tendon pathology, and may differentiate fibrous and cartilaginous coalitions.

In both types, the joint appears narrowed and irregular with cystic and sclerotic changes at the joint margin, but the intervening tissue type is indistinguishable.

4 3. MRI MRI can contribute additional information about marrow edema-like signal changes and tendon pathology, and may differentiate fibrous and cartilaginous coalitions. Fibrous or cartilaginous coalitions cannot be differentiated by CT. In both types, the joint appears narrowed and irregular with cystic and sclerotic changes at the joint margin, but the intervening tissue type is indistinguishable. 80% of patients with subtalar coalition also demonstrate edema-like signal changes in the subchondral bone adjacent to the site of coalition. Abnormal biomechanics may also produce tenosynovitis of the peroneal or flexor tendons. MANAGEMENT Symptomatic patients are initially treated conservatively through activity modification and/or use of a medial heel wedge, arch supports, and orthosis. Foot immobilization via casting may be attempted next if these initial treatment modalities fail. If all conservative approaches prove ineffective at relieving symptoms, surgical management may be indicated. Controversy exists as to the optimal operative approach to the treatment of subtalar coalition, and the choice of operative procedure may be influenced by multiple factors. In symptomatic patients without hindfoot arthrosis, surgical intervention aims at decreasing pain and improving motion, and, therefore, coalition resection is the preferred procedure. Although coalition resection may include the interposition of flexor hallucis longus tendon, 89% of resection patients are satisfied with the reduction in symptoms. In patients with associated degenerative disease, or in cases of failed resection, triple arthrodesis is usually performed.

5 Summary 1. Incidence: 50% each CN and CT coalition. C-N may be slightly higher 2. CN earlier presentation than T-C 2. Radiological signs: Ant eater, C sign, bar, Harris beath 3. Calcaneo-navicular bar: Excision and Fat graft: Olliers [C-N] 4. Talo-calcaneal bar: Excision if <50% [Wilde a hindfoot valgus of greater than 16 and a coalition surface area greater than 50% of the posterior facet on CT were predictors of poor results after resection.] 5. Hind foot is usually neutral: sometimes valgus and rarely varus 6. AD; ball-socket ankle; Hemimelia 7. Presentation after maturity: after warn about later triple

Tarsal Coalition On MR

Tarsal Coalition On MR By William Renner, M.D. This and other topics will be discussed in Tarsal coalition is a congenital anomaly with fusion of the tarsal bones. The fusion may be bony, fibrous or cartilaginous.