- Discussion:
- most common type of navicular frx;
- caused by a twisting force (usually eversion) applied to the foot;
- acute eversion of foot, resulting in increased tension on posterior tibial tendon or anterior fibers of deltoid ligament, places avulsion pull on navicular tuberosity, producing this fracture;
- note that this fracture often occurs along w/ compression frx of cuboid; & is part of a larger midtarsal frx;
- often avulsion of navicular tuberosity are considered to be an isolated injury, & attention is not given to entire mid tarsal joint complex;
- Exam:
- local tenderness, combined w/ pain on passive eversion or active inversion of the foot;
- Radiographs:
- frx is best viewed on AP and medial oblique x-rays of foot in equinus;
- accessory bones of the foot:
- two accessory osscicles, os supranaviculare & os supraatalare, can occur in this region;
- Treatment:
- small avulsion fractures are treated w/ short leg cast for 4 to 6 weeks;
- larger avulsion fractures can be treated w/ internal fixation;
- in some cases, a painful exostosis will develop, and this can be excised after frx healing