Summary Tarsal Navicular Fractures are rare fractures of the midfoot that may occur due to trauma or due to repetitive microstress. Diagnosis can be made with plain radiographs of the foot. Treatment is generally nonoperative with cast immobilization and non weight-bearing for the majority of fractures. Surgical management is indicated for nonunions, significantly displaced fractures, and for elite athletes. Etiology Navicular fractures can be traumatic navicular avulsion fractures mechanism is plantarflexion or eversion/inversion can involve talonavicular or naviculocuneiform ligaments navicular tuberosity fractures mechanism is eversion with simultaneous contraction of PTT may represent an acute widening/diastasis of an accessory navicular navicular body fractures mechanism is axial loading stress fracture mechanism of injury is usually due to chronic overuse often seen in athletes running on hard surfaces also common in baseball players considered a high risk injury due to risk of AVN most common complications include delayed union and non-union Spontaneous navicular AVN (Mueller-Weiss syndrome) Spontaenous navicular AVN is a rare disease that and can be seen in middle aged adults with chronic midfoot pain Anatomy Articulations navicular bone articulates with cuneiforms cuboid calcaneus talus Biomechanics navicular bone and its articulations play an important role in inversion and eversion biomechanics and motion Classification Sangeorzan Classification of Navicular Body Fractures (based on plane of fracture and degree of comminution) Type I Transverse fracture of dorsal fragment that involves < 50% of bone. No associated deformity Type II Oblique fracture, usually from dorsal-lateral to plantar-medial. May have forefoot ADduction deformity. Type III Central or lateral comminution. ABduction deformity. Presentation Symptoms vague midfoot pain and swelling Physical exam midfoot swelling tenderness to palpation of midfoot usually full ROM of ankle and subtalar joint Imaging Radiographs may be difficult to see and are often missed recommended views AP lateral oblique 45 degree radiograph best to visualize tuberosity fractures CT more sensitive to identify fracture than radiographs MRI will show signal intensity on T2 image due to inflammation Treatment of Stress Fractures Nonoperative cast immobilization with no weight bearing indications any navicular stress fracture, regardless of type, can be initially treated with cast immobilization and nonweight bearing for 6-8 weeks with high rates of success Operative open reduction and internal fixation indications high level athletes nonunion of navicular stress fracture failure of cast immobilization and non weight bearing Treatment of Traumatic Fractures Nonoperative cast immobilization with no weight bearing indications acute avulsion fractures most tuberosity fractures minimally displaced Type I and II navicular body fractures Operative fragment excision indications avulsion fractures that failed to improve with nonoperative modalities tuberosity fractures that went on to symptomatic nonunion open reduction and internal fixation indications avulsion fractures involving > 25% of articular surface tuberosity fractures with > 5mm diastasis or large intra-articular fragment displaced or intra-articular Type I and II navicular body fractures technique medial approach used for Type I and II navicular body fractures ORIF followed by external fixation vs. primary fusion indications Type III navicular body fractures navicular avascular necrosis technique must maintain lateral column length fusion of talonavicular and naviculocuneiform joints in navicular avascular necrosis