[Stress fractures of the tarsal navicular. Apropos of 20 cases].

Twenty cases of tarsal navicular stress fractures were observed in 17 patients. These fractures are rare, often go unrecognized, and are reputed to unite with difficulty. A clue to diagnosis was given by the description (young athletic person in sports involving sudden starts and stops). The lesion was not always visible on X-rays of the foot in supination and dorsal flexion (only 10 out of 20 in this series). Use of tomography and tomodensitometry was essential. Treatment was based on compressing the fracture with a screw without grafting or freshening, followed by immobilization of the foot with a cast and no weight bearing for 45 days. Union occurred in 19 out of the 20 cases. Thirteen patients were able to practice their sport without a loss of performance after a period ranging from 3 to 14 months. Treatment varied given the risk of spontaneous non union: incomplete fractures discovered early often responded to orthopedic treatment; fractures associated with large intra-osseous lytic lesions required addition of bone grafting. These fractures can be prevented through the use of inner arch supports especially if a predisposing factor exists such as a short first metatarsal bone.