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Review of Treatment of Metacarpal (Finger) Fractures

Fractures of the long bones of the fingers (called metacarpals usually only require casting and immobilization for a short time to promote healing. But if the fracture is separated (called displacement), unstable, or incongruent (broken ends don't line up correctly), then surgical fixation may be required.

Fixation refers to the use of Kirschner wires, condylar plates, or interfragmentary screws to hold broken bones together until healing takes place. The surgery may be done as an open or closed reduction and fixation. The goal is to restore normal bone alignment and joint function. Specific approaches depend on the location and severity of the fracture.

Metacarpal fractures can affect the metacarpal head, neck, or shaft. As the authors point out, there aren't too many studies comparing the different ways to repair these fractures. That's why they decided to review all the studies published in the last two years on this topic and summarize it by location of fracture.

Boxer's fracture affecting the metacarpal bone of the little finger is the most common fracture of the metacarpal neck. As the name suggests, the "neck" is the area between the long shaft of the bone and the round knobby end (the "head") that helps form the joint. With a neck fracture, the metacarpal head can poke out into the palm of the hand or rotate causing a deformity.

Typical treatment for Boxer's (metacarpal neck) fracture is just immobilization (nonoperative approach). If surgical fixation is needed, Kirschner wires are used. After surgery, the hand is placed in a cast or splint for up to a week followed by the use of a special metacarpal brace that allows use of the hand. Recovery can take a few months or more. The wires aren't removed for three months. Getting strength and motion back can take a bit longer.

Patients who have had surgery for this type of fracture report they do not like the looks of the scar. Patients who did not have surgery did not like the appearance of the hand (the fifth knuckle disappears without surgical repair). There is also a strange feeling in the hand reported when holding tools.

Fractures of the metacarpal shaft can also be repaired nonoperatively with immobilization. Like metacarpal neck fractures, fractures of the metacarpal shaft require surgery when there is malangulation, rotation, or loss of length of the bone. Type of fixation used depends on the size of the bone at the fracture site. Standard-sized screws may be too big or may reduce bone strength.

Kirschner wires can be used but sometimes they slip, twist or bend. Wires also tend to move or "migrate" causing a loss of reduction (the bone fracture separates more). The surgeon may choose to use more than one wire or to wrap the wire with stainless steel to help improve stability. Another option is the use of a "nail" (long pin) down through the inside of the bone shaft. This type of fixation is referred to as intramedullary nail fixation.

Two other types of fixation are reviewed and discussed. There is the interfragmentary screw and plate fixation and external fixation. The first type (interfragmentary) is used for long fractures of the shaft or spiral-shaped fractures around the shaft.

Interfragmentary screws are used with plates when there are many small fragments of bone, extensive soft tissue damage, and/or multiple fingers injured. Interfragmentary screw and plate fixation can also be used instead of wires. More recent studies have started looking at results based on strength of different screw and plate combinations as well as whether the plates are the locking or nonlocking kind.

And finally, external fixation (hardware is inserted through the skin and bone but located outside the finger). These devices are miniature in size and custom made. The advantage of this type of fixation is early motion while the fracture is still healing. Complications and results have not been reported yet with this type of fixation.

In summary, most metacarpal (finger) fractures can be treated without surgery. The surgeon realigns the bones and puts a cast on the patient's hand. Surgery to reduce the fracture and hold it in place (fixation) may be needed when there is separation of the fractured bone or instability. According to the studies reviewed, there isn't one single ideal fixation strategy. Each patient must be evaluated individually based on which finger is affected; type, location, and severity of fracture, and surgeon preferences.

Reference: Peter C. Rhee, et al. Update on the Treatment of Metacarpal Fractures. In Current Orthopaedic Practice. July/August 2012. Vol. 23. No. 4. Pp. 289-295.