5th Metatarsal Fractures
Fractures are common in the fifth metatarsal and normally occur with sporting activities. The metatarsal bones are a group of 5 long bones in the foot. The fifth metatarsal is located on the little toe side (lateral side) of the foot and connects to the little toe. Strong ligaments attach the base of the fifth metatarsal to the cuboid bone and the fourth metatarsal bone. Because of these strong ligament attachments, it is easier for an individual to fracture the fifth metatarsal than to dislocate it.
A fifth metatarsal fracture can occur in several ways and break in several places. There are 2 types of fractures that often occur in the fifth metatarsal:
- Avulsion fracture
- Jones fracture
A fifth metatarsal fracture is diagnosed by an x-ray showing a break in the bone. Because a Jones fracture may not show up on initial x-rays, additional imaging studies may be required.
In an avulsion fracture, a small piece of bone is pulled off the main portion of the bone by a tendon or ligament. This can occur after forced inversion or rolling in of the foot and ankle. Patient with an avulsion fracture experiences tenderness at the base of the fifth metatarsal, often with brusing and swelling at the site.
Treatment of non-displaced avulsion fractures is conservative. Options include elastic bandaging, low-profile walking boots or casts for 4 to 6 weeks. Weight bearing is allowed as tolerated.
However, for displaced avulsion fractures, they are best managed by either open reduction and internal fixation or closed reduction and pinning.
Jones fracture was first described by Sir Robert Jones when he fractured his fifth metatarsal in 1902 while dancing around a Maypole at a military garden party. Jones fracture involves a fracture at the base of the fifth metatarsal at the metaphyseal-diaphyseal junction, located 1.5cm distal to the tuberosity of the 5th metatarsal. It can either be a stress fracture (a tiny hairline break that occurs over time) or an acute (sudden) break.
Patients normally present with sudden pain at the base of the fifth metatarsal, with difficulty bearing weight on the foot. Bruising and/ or swelling are often present at the site. The mechanism of the injury is described as a laterally directed force on the forefoot during plantar flexion of the ankle.
Jones fracture is a difficult fracture to get to heal due to limited blood supply to that area and often surgery is required. If surgery is not performed, then a short leg cast can be worn for 6 to eight weeks in nonweight-bearing with progressive ambulation after cast removal. It can take 8 to 10 weeks for this fracture to heal and is not always predictable whether or not full healing will occur. Studies have shown about 70% heal with cast treatment.
On the other hand, sugery for Jones fracture has about 95% success rate. In competitive athletes, these fractures are usually treated surgically. Surgery may include placing an intramedullary screw into the bone’s shaft to stabilize the fractured bone, and hold it securely in place while healing occurs. This internal fixation technique allows healing to occur quite rapidly and walking on the foot with a removable boot is allowed within a few days after surgery. Typically, bike exercise can be commenced at about four weeks. Patients may return to running approximately six weeks post-surgery. – CT