II. Epidemiology
- Boys are affected at a younger age than girls
III. Pathophysiology
- Traction injury of peroneus brevis insertion at base of fifth Metatarsal
- Repeat microtrauma to peroneus brevis insertion
IV. Signs
- Fifth Metatarsal base pain, swelling, tenderness
- Provocative maneuvers
- Resisted Eversion
- Passive Inversion
- Plantar Flexion
V. Imaging
-
Bedside Ultrasound or XRay
- Fragmentation and widening of the apophysis (or normal)
- MRI
- Indicated to evaluate for alternative diagnosis (e.g. Stress Fracture suspected)
VI. Differential Diagnosis
-
Fifth Metatarsal Fracture
- Acute inversion injury with avulsion Fracture
- Os Vesalianum (normal accessory bone)
- Smooth rounded bone edges (contrast with irregular edges of Apophysitis)
VII. Management
- Relative rest
- Hard-soled shoe (indicated if pain is severe)