[Synostosis and tarsal coalitions in children. A study of 68 cases in 47 patients]

The authors report their experience with tarsal coalitions in children. The purpose of this study was to discuss the origins of the << too long anterior process >> of the calcaneum, and to propose a simple therapeutic strategy for diagnosis and treatment.

The study included 47 children (68 feet), with one or more idiopathic tarsal coalitions. All patients had physical examinations to record symptoms, morphology of the foot, mobility of the foot, gait analysis, standard radiographs, and in some cases CT scans or MRI. The average age of the patients was 11.5 years old, 7 patients had a positive family history for tarsal coalitions. 66 per cent of the patients had mild tarsal pain or a history of repeated ankle sprains. The conservative treatment concerned 28 feet: 3 casts, 2 injections of corticosteroids into the subtalar joint, insole-shoes in 3 cases, and abstention in 20 cases. The operative treatment (40 feet) consisted of resection of calcaneonavicular coalitions (24 feet) resection of talocalcaneal coalitions (3 feet), mediotarsal and subtalar arthrodesis (8 feet), resection of calcaneonavicular coalition combined with the ""Cavalier'' procedure described by Judet (3 feet), calcaneal osteotomy (2 feet).

The mean follow-up was 42 months. The morphology of the involved foot was normal in 33 cases, flat foot was seen in 24 cases (4 peroneal spastic flat feet), pes cavus in 3 cases, club foot in 2 cases, pes varus in 4 cases, ""Z'' shaped feet in 2 cases. The radiological examination was demonstrative of tarsal coalition in 61 feet. 7 tarsal coalitions were seen during operative procedures. The location or the coalition was calcaneonavicular (57), talocalcaneal (16), talo-navicular (8), calcaneo-cuboid (7), naviculo-cuneiform (4). The secondary radiographic signs were studied for each foot. In the conservative group, 2 patients degraded their clinical status, one developed a spastic flat foot. In the surgical group, all except 2 patients had good clinical and functional results. One patient had persistent pain in the subtalar joint after a technically correct calcaneonavicular resection. One patient had recurrent spastic flat foot following isolated talocalcaneal resection in a foot presenting multiple tarsal coalitions. This patient was reoperated by a mediotarsal and subtalar arthrodesis with a good result.

The authors believe that tarsal coalitions have to be recognized based on a history of repeated ankle sprains or subtalar pain. Pain radiographs are diagnostic in most cases. CT scans and MRI are useful when radiographs are negative, especially in young children, or for talocalcaneal coalitions. The authors believe that the ""the too long anterior process'' of the calcaneum in calcaneonavicular coalition has the same embryologic origin. Operative treatment is suitable, when tarsal coalitions are symptomatic or after failure of conservative treatment. Resection gives good results with calcaneonavicular coalitions and selected talocalcaneal coalitions. The mediotarsal and subtalar arthrodesis is suitable in spastic flat foot, or when the bony-bridge is too big, or when the involved joint presents degenerative changes in these cases, the MRI is very useful to select patient for resection or for arthrodesis.

Evocative history and plain radiographs are diagnostic of most tarsal-coalitions. Modern imagery is useful for difficult diagnostics, for young children, or for evaluation of a joint before resection or arthrodesis. Resection is a good treatment for calcaneonavicular coalitions and gives good results for talocalcaneal coalitions in selected patients.