Definition

The fracture of the forearm refers to the break of one or both forearm bones, the radius and ulna.

Pathology

In adults, the fracture of the forearm accounts for most arm fractures. They frequently involve both the radius and ulna. If only one bone is broken, it is usually the ulna. In children it is critical to evaluate the fracture in relation to the growth plate (or physis) of the radius and ulna, as injury to the growth plates can compromise full bone growth. The classification of forearm fractures differs in adults and children and consequently their treatment management.

Classification

The fractures of the forearm are classified according to the location of the break, whether occurring close to the elbow (proximal), near the wrist (distal) or in the length between these joints (also named shaft or diaphysis). They are also defined by the specific characteristics of the fracture. Below some of the most used classification systems:

Closed fracture, when the extremities of the fractured bone are contained within the soft tissue and the skin is intact

Open fracture, when the extremities of the bone protrude through a wound

Simple fracture, when the bone break maintains the bone anatomical alignment

This classification of forearm fractures is often used in adults and children:

Growth plate fracture: occurs in children and refers to a fracture including the physis (growth plate at either end of the bone where cartilage grows and becomes ossified bone)

Greenstick fracture: is a partial fracture of the bone only found in children. The periost (skin covering the bone) around the fracture is intact

Torus fracture (buckle fracture): compression of the top layer of bone with bending of the opposite bone side. The broken bones are undisplaced

Metaphyseal fracture: is a fracture of the upper or lower section of the bone shaft, outside the growth plate

The Orthopaedic Trauma Association classification of radial and ulna diaphyseal (shaft) fractures includes:

Type A: simple fracture of ulna (A1), radius (A2), or both (A3)

Type B: wedge fracture of ulna (B1), radius (B2), or both (B3)

Type C: complex fractures

Associated injuries

Forearm fractures often occur together with other injuries to the wrist and elbow and are also associated with soft tissue injuries to nerves, more likely the radial nerve, which may result into drop hand. Injury to vessels may involve the radial and ulnar arteries. As a consequence of a fracture the patient may develop a compartment syndrome, which consists of increased swelling and pressure of the soft tissues around the forearm fractures.

Causes

Fractures to the forearm can be produced by high-energy trauma or low energy falls. Forearm fractures are more frequent in males. The main causes are:

Fall on a hard surface with outstretched arm

Motor vehicle accidents

Direct blow to the forearm (nightstick, baseball bat)

Forceful twisting of the forearm pushing the elbow beyond its normal range of movement caused by automobile and motorbike accidents

Machinery accidents

Cancer metastases to the bones (pathological fracture)

Gun shot

Risk factors

A number of recreational sports and ageing constitute typical factors that increase the risk of forearm fractures:

Sports (skate-/snow-boarding)

Contact sports (football, rugby, soccer)

Motor vehicle and motor bicycle driving

Manoeuvring of farming and industrial machines

Elderly individuals prone to falls

Postmenopausal women

Osteoporotic bones

Congenital bone conditions

Symptoms

The typical symptoms of forearm fracture are:

Acute, sharp pain in the forearm at time of injury

Pain increasing with movement

Swelling around the fractured bone(s)

Deformation of the arm, flopping arm

Bleeding

Feeling of bone fragments when moving the forearm

Patient inability to straighten or rotate the arm as a consequence of the fracture

Treatment

Nonoperative treatment

Early management of forearm fractures is usually provided at the Emergency Department. If fractured bone fragments are not displaced or minimally displaced and do not impact on elbow or wrist joint movement, conservative treatment is recommended. This comprises an early closed reduction performed by an orthopaedic surgeon to realign the fractured bone(s), followed by the immobilisation using a splint, a cast or a brace above the elbow. A splint is worn for 6 weeks in the more simple cases and a cast between 6 and 10 weeks in more complex fractures. Additional conservative treatment aims at reducing swelling, pain and inflammation with:

Arm elevation

Ice pads

Analgesics (pain killers)

Administration of NSAIDs

Surgical treatment

Surgery is necessary in significantly displaced, comminuted and / or open fractures or in case of high instability when both forearm bones are fractured. The option of surgery will also depend on the age, general health and the osteoporotic nature of the bone. Several approaches are available to fix the fractures of the forearm, including:

Open reduction and internal fixation (ORIF) consists of a large skin incision, a plate inserted along the fracture length that is fixed with screws. It is the most common method. It may require the employment of bone graft especially with bone loss due to comminuted or open fractures

Intramedullary rod or nail, a metal introduced in the bone shaft canal and fixed on the outer bone extremities with screws. The rod can be introduced either from the proximal or distal end of the bones

External fixation via percutaneous screw fixation is used to maintain bone alignment while the fracture is healing. This is often followed by permanent internal fixation within 14 days after the injury. This method is used in situations where an immediate internal fixation cannot be performed, eg. multiple injured patients and in open fractures with high risk of infection transmitted to the bone. In rare cases the external fixator remains in place until the fracture has healed.