The Common Vein Copyright 2011
Definition
Fractures of the navivular are usually caused by irect trauma or axial loading. and are often characterized by
Cortical avulsion fractures occur when there is excessive flexion or eversion of the midfoot. The talonavicular capsule and the anterior deltoid ligament fibers are prone to avulsion.
Tuberosity fractures occur when there is eversion and posterior tibial tendon contraction that can cause a diastasis of an accessory navicular.
Navicular body fractures are usually due to axial loading. The Sangeorzan Classification includes three types. Type I are transverse, type II are oblique, and type III are with central or lateral comminution with abduction.
Navicular stress fractures are most common in runners and basketball players.
The fracture may be complicated in the acute phase by neurovascular injury, or in the subacute or chronic phases by nonunion, malunion, infection, osteonecrosis, and osteoarthritis.
The diagnosis of this injury is usually made by a combination of physical examination and x-ray imaging.
Imaging includes the use of plain x-rays, and if indicated CT-scan, or MRI.
Avulsion fractures are treated with immobilization and possible excision of bone fragments. If greater than 25% of the articular surface is disrupted as result of the fracture and ORIF procedure is required.
Tuberosity fractures are treated with surgery if there is greater than 5mm of diastasis or intra-articular fragments. Most of these injuries are treated with a few weeks of immobilization.
Body fractures with minimal displacement are treated non-operatively with immobilization for types I and II injuries. When there is significant displacement and joint disruption, surgery is required. Type III injuries can require an ORIF with possible external fixation.
Stress fractures are treated non-operatively initially but can require surgical fixation if they persist.
The Normal Navicular Oblique Projection |
| Courtesy Ashley Davidoff MD 46713c02.800 |
The Navicular from Above |
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The 3D reconstructed CT scan of the forefoot exemplifies the normal anatomy of the distal tibia, fibula, tibio-talar joint, talo navicular joint, and navicular cuboid. The cuneiforms are also well visualized. This patient does have an avulsion fracture off the navicular but it is not obvious on this view. Courtesy Ashley Davidoff MD 72585 |
References
Davis MF, Davis PF, Ross DS. Expert Guide to Sports Medicine. ACP Series, 2005.
Elstrom J, Virkus W, Pankovich (eds), Handbook of Fractures (3rd edition), McGraw Hill, New York, NY, 2006.
Koval K, Zuckerman J (eds), Handbook of Fractures (3rd edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.
Lieberman J (ed), AAOS Comprehensive Orthopaedic Review, American Academy of Orthopaedic Surgeons, 2008.
Moore K, Dalley A (eds), Clinically Oriented Anatomy (5th edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.
Wheeless’s Textbook of Orthopaedics: Navicular Body Fractures (http://www.wheelessonline.com/ortho/navicular_body_fractures)