The fifth metatarsal
is commonly fractured if one is an active
person. There are several different classifications of these fractures, most almost identical unless one is trained and experienced in such things. There are two
main categories of fractures:
- Proximal : these include acute fractures of the metaphysis (tuberosity), commonly refered to as the dancer's fracture. Also, the Jones fracture, stress fractures of the proximal diaphysis, and acute-on-chronic diaphyseal fractures are placed in this category.
- Distal : including intra-articular metatarsophalangeal fractures as well as midshaft and neck fractures
A fracture of the base of the fifth metatarsal (the dancer's fracture) typically occurs with inversion injuries to the ankle and may accompany an ankle sprain. In other words, the dancer's fracture is an injury to the bump connecting the fifth metatarsal to the tarsus.
The term Jones fracture is used to describe several different types of fractures of the proximal fifth metatarsal. The true Jones fracture, originally described in 1902 by Sir Robert Jones, consists of a transverse fracture at the junction of the diaphysis and metaphysis. In other words, the Jones fracture is when someone breaks their fifth metatarsal right between the bump connecting to the tarsus and the skinny part of the bone.
A stress fracture is commonly encountered in athletes who do a lot of running, most often soccer players. Soccer shoes tend to be very narrow, tight-fitting shoes that allow the fifth metatarsal to hang over the sole laterally. This is not a good thing, and can lead to injury.
Acute-on-chronic fractures are basically the same as Jones fractures, except that they display cortical thickening and a lucency in the lateral cortex. In other words, they heal funny.
Midshaft and neck fractures: With athletic activity, direct trauma to the fifth metatarsal midshaft and neck may result in fractures. This is when the thin part of the bone is fractured more towards the toes.
Intra-articular metatarsophalangeal fractures: In active people, metatarsal head fractures may occasionally result from direct trauma, and these injuries require careful evaluation. The intra-articular fragment is usually displaced in the plantar and lateral direction. A subtle osteochondral fracture pattern can be noted secondary to shear injury from dorsal dislocation of the metatarsophalangeal joint. These are bad and often serious. Sometimes these fractures require a pin to be surgically implanted in the bone to regain foot strength and mobility.
Info obtained from the emergency room doctor on duty friday night at the Holland Community Hospital in Holland, MI. Additional information found at www.physsportsmed.com, www.aafp.org, and www.gentili.net.