Navicular stress fracture injury: observational use of plantar pressure measures in elite AFL footballers

Background Navicular stress fracture (NSF) is a relatively uncommon injury according to Australian Rules Football (AFL) injury surveillance data. Like all stress fractures, a disproportionate amount of compression / strain (dose) versus remodeling (response) accounts for bone breakdown. The exact mechanism of injury or anthropometric factors involved in navicular stress fracture remains largely unknown however; several authors speculate a short first metatarsal and metatarsus adductus as contributing factors. It is thought that a long second metatarsal transmits forces unevenly through the medial cuneiform creating shearing stress at the avascular central zone of the navicular. To date no prospective data is available to support these theories. Navicular stress fracture is deemed high risk due to the potential of delayed or non union and often excessive time away from activity.