Navicular Stress Fracture

Navicular stress fracture is a high-risk stress fracture of the tarsal navicular, typically in young athletes in running, sprinting and jumping sports, ballet and military training.

BOFAS describes the navicular as the second most common stress fracture site in the foot. Pain is vague, dorsal and midfoot, worse with activity and eased by rest. Plain radiographs are often normal, and symptoms commonly last months before diagnosis.

It is high risk because the central third is relatively hypovascular and heavily loaded: if missed or under-treated, it can fail to unite, displace or complete.

The navicular forms the apex of the medial longitudinal arch. It articulates with the talus proximally, the 3 cuneiforms distally and the cuboid laterally, and tibialis posterior inserts on its tuberosity.

Medial and lateral vessels supply the bone but leave a relatively hypovascular central third. Stress fractures occur here, usually in a sagittal or near-sagittal plane, as the navicular is compressed between the talar head and the cuneiforms under repetitive load.

Predisposing factors:

• •Training error: a sudden rise in volume or intensity, or a change of surface
• •Biomechanics: cavus foot, restricted ankle dorsiflexion, short first metatarsal, metatarsus adductus
• •Bone health: relative energy deficiency in sport (REDs), low bone mineral density, vitamin D deficiency
• •Sport: sprinting, jumping, ballet en pointe, loaded military marching