ACUTE NAVICULAR FRACTURE

History
. History of trauma
. Midfoot pain and swelling
Physical exam
. Swelling and exquisite pain on dorsomedial aspect of midfoot
. Dorsal lip avulsion – two ligaments insert on dorsum of navicular
. Dorsal talonavicular
. Stressed with inversion and plantarflexion
. Anterior aspect of deltoid ligament
. Stressed with eversion
. Tuberosity fractures
. Result of acute valgus or eversion injury increases stress on posterior
tibialis tendon
Studies
. AP, oblique, and lateral radiographs
. Examine closely formidtarsal joint (Lisfranc) injuries
. Bone scans, CT scan, MRI for occult fractures
. Differentiate acute tuberosity fracture fromaccessory navicular
. Accessory navicular is smooth and regular
Differential diagnosis
. Cuneiformand cuboid fractures
. Navicular stress fracture
. Running or jumping athletes
. Navicular avulsion fracture
Treatment
. Dorsal lip avulsion
. Conservative
. Weight-bearing cast for 4–6 weeks
. Open reduction and internal fixation if fragment is>25% of navicular
. Displaced acute fractures treated with anatomic and stable internal
fixation
. Anatomic reduction of talonavicular joint more critical
. Mobility of this joint is important for function
. Anatomic reduction of anterior and distal navicular not critical
. Naviculocuneiformjoints have littlemotion
Disposition
N/A
Prognosis
. Navicular is largely covered with articular cartilage
. Notmuch room for nutrient vessels to enter
. Makes the tarsal navicular subject to osteonecrosis
Caveats and Pearls
. Located in the uppermost part of the arch, the navicular is the keystone
for vertical stress on the arch
. Anatomic reduction essential to restore talonavicular motion