The navicular plays an important role in maintaining the medial longitudinal arch of the foot. Commonly, fractures of the navicular are not evident on plain radiographs. This often leads to a delay in diagnosis, which may result in prolonged disabling foot pain in individuals, particularly young athletes. The 4 types of navicular fractures are (1) cortical avulsion, (2) tuberosity, (3) body, and (4) stress.
Cortical and tuberosity avulsion fractures
Avulsion fracture, the most common fracture of the navicular, is often associated with ligamentous injuries and results from twisting forces on the mid foot. These fractures are commonly treated conservatively, except for avulsion of the posterior tibial tendon insertion (tuberosity fracture), which may be repaired operatively, especially if a proximal dislocation of 1 cm or more is present. An avulsion of the posterior tibial tendon insertion must be differentiated from an accessory navicular (see Other Problems to Be Considered).
Fractures of the navicular body
Fractures of the body are commonly associated with other injuries of the midtarsal joint. Sangeorzan et al categorized navicular body fractures into 3 types, as follows
Type 1 is a coronal fracture with no dislocation.
Type 2 is a dorsolateral to plantomedial fracture with medial forefoot displacement.
Type 3 is a comminuted fracture with lateral forefoot displacement and carries the worst prognosis.
All navicular body fractures with 1 mm or more of displacement require open reduction and internal fixation.
The rest of this article primarily discusses the diagnosis and treatment of navicular stress fractures, which are usually sports-related injuries.
In 1855, Brehaulpt first described stress fractures in military recruits who were subjected to long marches. As more civilians took up physically demanding sports, the incidence of stress fractures has increased in the general population. Towne et al first described stress fracture of the tarsal navicular in 1970.
In athletes, navicular stress fractures are of particular concern because they are underdiagnosed and can lead to significant disability if the diagnosis is delayed.
In a study by Torg et al in 1982, the average time between the fracture and diagnosis was estimated to be 7 months.
Given the significant improvement in outcome with early diagnosis and proper treatment, navicular stress fractures should be considered in any athlete with midfoot pain. In a 2006 study by Saxena and Fullem, navicular stress fractures took up to 4 months to heal posttreatment.
Fracture-dislocation of the navicular may occur in athletes.
This uncommon injury generally requires reduction and examination for stability via fluoroscopy, with the patient under general anesthesia. If the postreduction examination findings confirm stability of the navicular, treatment with a non–weight-bearing cast may be sufficient; otherwise, internal fixation is required.