Metacarpal fractures

There are many different types of metacarpal fractures. This article takes you through

• undisplaced fractures, which generally don't require surgery
• displaced fractures, which may require surgery
• fractures involving the joint surfaces, which generally require surgery
• the different types of treatment and surgeries that may be used for metacarpal fractures
• examples of specific types of metacarpal fractures

Metacarpal fracture - undisplaced

Some metacarpal fractures require surgery and some don't. If your metacarpal fracture is stable and undisplaced (ie the fragments are still in their normal position) it is unlikely that you will need surgery. Your fracture can be treated with splinting, taping or casting (or a combination of all three of these). Generally a cast is only used for treating metacarpal fractures for children or individuals who will not be able to keep their fingers safely immobilised with a splint. The disadvantage of a cast is that you cannot remove it to exercise your fingers, so your joints may become stiff. Wearing a splint protects the fracture while it is healing, but still allows you to remove the splint to perform the finger exercises prescribed by your hand therapist. If you are able to keep the joints mobile this means that when your fracture is strong enough to allow full use of your hand then you won't be limited by stiffness - so your rehabilitation time is faster.

The speed of fracture healing can be affected by factors such as the type of fracture, your health and your ability to comply with therapy. Usually it is safe to start gentle exercises in a finger with an undisplaced fracture at 3-4 weeks. Speak with your surgeon and hand therapist to determine what is the right time for you, and what sort of exercises you should perform. You will be permitted to do light activities (such as eating a meal) when the fracture is not yet fully healed. At 6 weeks you are usually safe to start using your hand without restrictions. You may be advised to avoid heavy loads or contact sports until 8 weeks. Often you may be advised to strap your injured finger to another finger for support when you initially stop wearing your splint, or during the first few weeks of activity. Your surgeon and hand therapist will be able to advise what is best for you and when you can safely return to normal activities. One of the most common questions patients ask is "When can I drive?". Click here for more information on driving in Victoria with a hand injury or after hand surgery.

Metacarpal fractures - displaced or unstable

If a metacarpal fracture is displaced or if the fracture pattern is unstable it is likely that surgery will be recommended. If you need surgery it is best that this be performed within 2 weeks of your fracture. Displaced fractures are likely to heal with shortening, or angulation, or rotation. These three problems can lead to functional problems with your hand, because your finger will not function in the same way once the fracture heals.

Surgery to fix the fracture can be done in a variety of ways. In some instances your surgeon may tell you about two different ways, and allow you to suggest which you think would work best for you. More commonly your doctor will recommend one particular type of surgery taking into consideration your injury and factors like your occupation, hand dominance, hand use and preferences, explaining why the recommended treatment is the best for you. If your occupation places low stresses on your hands and fingers (such as typing on a computer) you will be able to return to work duties earlier than if your occupation requires heavy manual work. 

Metacarpal intra-articular fractures

Intra-articular fractures involve the joint surface. It is very important that intra-articular fractures are treated properly to reduce the risk of post traumatic osteoarthritis. Generally speaking, if the joint fragments are displaced by more than 1mm it will be recommended that you have surgery, because an irregular joint surface carries a high risk of developing arthritis subsequently.

In most instances surgery is successful in realigning the joint surfaces. If the joint surface is broken into multiple small fragments this is a "nasty" fracture because it is very difficult to repair the joint. If the joint cannot be successfully repaired the subsequent options may include:

- living with a stiff or painful joint

- having a joint fusion (a fused joint is not painful, but it does not move)

- having a joint replacement

Types of surgery for metacarpal fractures

The type of surgery that is performed differs and is largely determined by the type of fracture. The common options are:

- Closed Reduction (this is commonly referred to as a "GAMP", which stands for "General Anaesthetic, Manipulation and Plaster)

This involves manipulation of the fracture under anaesthetic (either local anaesthetic, sedation or general anaesthetic). The displaced fracture is pulled back into position and the fracture is held in position with a splint or cast. This method of treatment is not suitable for unstable fractures, as these fractures will not be able to be held in position with a splint or cast. You will be permitted to start gently moving the finger at 3-4 weeks after the manipulation. This type of treatment is not commonly useful in metacarpal fractures as the bones can't be adequately held in position.

- General Anaesthetic Manipulation and Plaster (GAMP) and K-wire

This involves manipulation of the fracture under anaesthetic. The displaced fracture is manipulated into position and temporary K-wires are inserted through the skin to hold the bone fragments in the correct position. A splint or plaster is then applied. The K-wires are usually removed at 3-6 weeks after surgery. While the K-wires are inside you it is not permissible to move the affected finger, because the wires can bend or break, or cause injury to tendons. Once the wires are removed you will be permitted to start gently moving your finger.

- Open Reduction and Internal Fixation (ORIF)

If you have a displaced or unstable fracture then ORIF treatment is commonly recommended. This surgery involves using wires, screws, or a plate and screws, to hold the bone fragments together solidly. Early movement of the finger is recommended after ORIF treatment to prevent stiffness that can result from scar tissue forming in the tissue planes that were traversed in the surgery. It is still necessary to wear a splint to prevent the finger from forces that could pull apart the metal fixation, but you are able to keep your joints supple through regular gentle exercise. As the fracture heals you are able to put increasing force through the fracture. You are usually able to commence full activities at 6-8 weeks.

The use of internal permanent wires to stabilise a metacarpal fracture is called the Bouquet technique. In the surgery wires are placed within the metacarpal bone, within the "medullary" canal. This technique is appropriate for certain fracture patterns, but generally screws +/- a plate will provide more rigid stability, which means an earlier start to your rehabilitation. Discuss the options with your surgeon, who will be able to advise what is the most appropriate treatment type for you.

Examples of specific types of metacarpal fractures

• 5th metacarpal neck fracture (below) - known as a "boxer's fracture", as it commonly results from a punching injury.

• Metacarpal shaft fracture (below). This is a fracture through the "shaft" of the bone, which is the middle section. These fractures tend to be unstable and if they are displaced or multiple (as in the picture below) surgery will be recommended.
• 1st metacarpal base intra-articular fracture (below). This is commonly referred to as a "Bennett's fracture" - so named because it was described by Edward Hallaran Bennett, Professor of Surgery (1837–1907) at Trinity College of the University of Dublin in 1882. This is the injury sustained by Real Madrid goalkeeper Iker Casillas in January 2013. Surgery is generally recommended because the fracture involves the joint surface, and because the joint tends to dislocate or become unstable at the time of the surgery. Surgery may involve wires or screws.

• A Rolando fracture is similar to a Bennett's fracture, as it also involves a fracture involving the joint surface of the base of the 1st metacarpal bone. In this type of fracture there are three distinct fragments, whereas in the Bennett's fracture there are only two fragments. It was described in 1901 by Silvio Rolando.

Image credit: hand skeleton images created with DrawMD.