A break in one or both of the bones in the lower part of the arm is called a forearm fracture.
The two bones in the forearm are the radius and the ulna. The radius is the bone nearest your thumb and the ulna nearest the little finger. A strong membrane between the two bones holds them close together but allows them to rotate around each other to a certain degree. At the proximal (upper) end of the bones, the ulna articulates with the radius and the humerus (upper arm bone) to form the elbow joint, and at the furthest (distal) end, the radius articulates with the ulna and three of the wrist bones. Together they allow a great deal of mobility in the arm, wrist, and hand.
Forearm fractures can happen at any location along the length of the bones and may involve muscles, tendons, or ligaments. There are several types of fracture that may or may not involve the elbow or wrist joints. The various fractures include:
Torus fracture: Often called a buckle fracture. Compression of the top layer of bone causes the other side of the bone to bend. The broken bones are still in position.
Greenstick fracture: Only children sustain these fractures. Part of the bone is broken, but not all the way through.
Metaphyseal fracture: Refers to a fracture of the metaphysis (the upper or lower part of the bone shaft) but does not involve the growth plate.
Growth plate fracture: A fracture involving the physis (growth plate found at either end of the bone where cartilage gradually becomes bone). The growth plate of the radius at the wrist end is the most common location for this fracture. Most fractures of this sort heal well with no residual bone growth problems.
Colles’ fracture: A fracture that extends across the end of the radius. This injury is more common in adults due to bone brittleness.
Galeazzi fracture: An injury that combines a fracture of the radius, with displaced pieces of bone, and a dislocation of the ulna at the wrist.
Monteggia fracture: Again, this injury involves both forearm bones, but in this instance the location is at the proximal end of the forearm, the ulna is fractured and the radius dislocated.
Up to half of all childhood fractures are forearm fractures, and of these, about three-quarters are fractures of the radius, near the wrist.
A fall onto an outstretched arm is the most common cause of a forearm fracture. Falls from monkey bars at school are notorious for causing such injuries. Other traumatic causes may include a heavy blow to the forearm or a twisting of the arm that forces the elbow beyond its normal range of motion. Examples of such situations are motor vehicle accidents or contact sport accidents.
Some diseases or conditions can increase the risk of sustaining a forearm fracture. These include osteoporosis, congenital bone conditions, the normal aging process, poor nutrition, and decreased muscle.
- Pain, possibly severe, made worse with movement of the elbow or wrist
- Possible numbness in the forearm and hand
- Deformity of the forearm, for example an unusual curve or lump
- Tenderness, swelling, and possible bruising of the forearm, wrist or hand
- Inability to turn the palm of the hand up or down
Diagnosis of a forearm fracture is based on questions about the circumstances of the injury, your symptoms, a physical examination of the arm, and X-rays. Computed tomography (CT) scans may be used to view the soft tissues in the forearm, such as cartilage and tendons. Your doctor will also check blood flow and nerve responses in the hand and fingers to rule out damage to the blood supply or nerves.
While waiting to see the doctor a splint can be applied to the underside of the hand, wrist, and forearm. The arm should be elevated, if possible. An ice pack, placed on the injured area, will start to reduce swelling. It is important not to try to realign any bones, but instead seek medical attention.
If the fractured bone or bones are still in their correct position, and the fracture is relatively straightforward, treatment will consist of immobilizing the bones while they heal. This is achieved with a cast or splint. Depending on the injury, the splint may be only on the forearm, or it may cover the arm from the hand to above the elbow.
A simple fracture usually requires 3-4 weeks in a cast, while a more complicated injury may need 6-10 weeks.
Pain medication may be prescribed, or you can take, with medical approval, over-the-counter pain relieving medicines such as acetaminophen (Tylenol).
Elevating the forearm above the level of the heart whenever possible will help to reduce swelling and thereby relieve pain.
Sometimes the doctor is able to realign displaced bones by physically manipulating them without the need for surgery. If not, or if the bone fragments are unstable and unlikely to remain in position for healing, if the bone has pierced the skin, or if the bones have already begun healing but they are incorrectly aligned, surgery will be needed. Orthopedic fixing devices such as screws, pin, or plates may be used to hold the bones in place until healing is complete.
The degree of recovery depends somewhat on the age and general health of the patient. A child will recover much more rapidly and with a greater chance of regaining full mobility of the wrist and elbow joints. An older person may never regain total pre-injury mobility, and may also have an increased risk of developing carpal tunnel syndrome as a complication of the injury.
After the cast has been removed, the elbow and wrist joints will probably be stiff, but with time and movement the stiffness will usually go away. The muscles of the forearm and joints will have weakened through lack of use, and the actual bones themselves will still be slightly fragile. Care should be taken for a few weeks to allow strength to build up again.
If the fracture involved the growth plate in a child, regular monitoring by a physician is recommended, to make sure that the bones are growing normally.