eMedicine Specialties > Orthopedic Surgery > Hand & Upper Extremity
Forearm Fractures
Updated: Dec 19, 2008
Introduction
The forearm is a complex anatomic structure serving an integral role in upper extremity function. The dexterity of the upper limb depends on a combination of hand and wrist function and forearm rotation. The forearm bones can be considered struts linking 2 halves of a condylar joint formed by the proximal and distal radioulnar joints. Thus, any change in the geometry of the radius or ulna alters the congruency and range of motion of this condylar joint.
Closed fracture of the forearm in the middle-third area is complicated by compartment syndrome, with early blisters and a tense compartment.
The same patient as in Image above, with fasciotomy and external fixation to the radius and intramedullary nailing of the ulna.
Sequestrum of the proximal radius. Sequela to an open fracture of the radius and ulna and multiple surgeries.
Malunion, especially shortening and angulation of the radius or ulna, may cause functional problems at the wrist or elbow. If functional disability is to be avoided following fracture, precise anatomic reduction is necessary.
As a result of the complex arrangement of neurovascular structures surrounding the radius and ulna, surgical approaches to the forearm for fracture fixation require particular care in planning and execution.
This article addresses injury to the diaphyseal radius and ulna, as well as associated injury to the distal and proximal radioulnar joints.
Related eMedicine topics:
Fracture, Forearm
Distal-Third Forearm Fractures
Middle Third Forearm Fractures
Elbow and Forearm Overuse Injuries
Problem
To restore the functional dynamics of the upper limb, very careful attention must be paid to accurate reconstruction of injured structures.
In children, rapid bone-healing times and the possibility of remodeling with growth allow conservative treatment much of the time.1 In adults, nonoperative treatment in the form of plaster casting is often inadequate to ensure anatomic reduction and healing. Achieving anatomic reduction by closed methods is difficult and. often, maintaining a reduction is impossible.
For an optimal result, the basic rule is that a stable anatomic reduction with preservation of mobility must be achieved. Operative treatment is therefore the rule, rather than the exception, in adults, the treatment principles of the AO group (Arbeitsgemeinschaft für Osteosynthese, or Association for the Study of Osteosynthesis) have revolutionized treatment of radius and ulna fractures.
Frequency
The literature provides few detail in regard to the incidence of fractures of the radius and ulna in adults. McQueen and his coworkers have comprehensively analyzed the incidence of forearm fractures seen at the trauma unit of the Royal Infirmary of Edinburgh over a 3-year period. This unit caters exclusively to adult trauma cases in a specified area and population and thus is a very good guide to the epidemiology of forearm fractures in a westernized country. The causes of injury included direct trauma, fall from a height, road traffic accidents, and sporting injuries. Unlike in other regions, injuries related to gunshots and firearms are not prevalent as a cause of injury in this region. Of the 2812 fractures, just 5% were diaphyseal forearm fractures, and an overwhelming majority of 76% were distal radius fractures.
Data from the National Hospital Ambulatory Medical Care Survey show that radius and/or ulna fractures account for 44% of all forearm and hand fractures in the United States.2
Etiology
The mechanism of injury is variable. The most common cause is a direct blow to the forearm, producing a single (nightstick) fracture of the ulna, radius, or both. The next most likely mechanism is a fall on an outstretched hand with the forearm pronated. Other mechanisms of injury include road traffic accidents and athletic injuries. The force generated is usually much greater than that required to cause a Colles fracture. Most forearm shaft fractures resulting from falls occur in athletes or in persons who fall from heights.
Gunshot wounds can result in fracture of both bones of the forearm. These injuries are commonly associated with nerve or soft-tissue deficits and frequently have significant bone loss. Severely debilitating and mutilating injuries are caused by accidents involving farmyard machines and industrial machinery. These severely mangled extremities pose a challenge from the time the decision is made to salvage the limb until the final result.
Pathophysiology
Fractures of both bones of the forearm are usually classified according to the level of fracture, the pattern of the fracture, the degree of displacement, the presence or absence of comminution or segment bone loss, and whether they are open or closed. Each of these factors may have some bearing on the type of treatment to be selected and the ultimate prognosis. Disruption of the proximal or distal radioulnar joints is of great significance to treatment and prognosis. Determining whether the fracture is associated with joint injury is imperative because effective treatment demands that both the fracture and the joint injury be treated in an integrated fashion.
Presentation
Nondisplaced diaphyseal fractures of the shafts of both bones of the forearm are rare, and the deformity is often obvious, with the patient supporting the deformed and injured limb with the other hand. The symptoms include pain, deformity, and loss of function of the forearm. In these cases, excessive manipulation of the arm should be avoided to prevent further damage to the soft tissues.
Clinical examination should include a careful neurologic evaluation of the motor and sensory functions of the radial, median, and ulnar nerves. Check the vascular status and amount of swelling in the forearm. A tense compartment with neurological signs or stretch pain should arouse the suspicion of compartment syndrome (see first Image below and Image 1 in Multimedia), and compartment pressures should be measured and monitored. This may be of significance in polytrauma patients or in comatose or obtunded patients. A low threshold should be maintained when deciding whether a fasciotomy is needed in patients with impending compartment syndrome (see second Image below and Image 2 in Multimedia).
Closed fracture of the forearm in the middle-third area is complicated by compartment syndrome, with early blisters and a tense compartment.
The same patient as in Image above, with fasciotomy and external fixation to the radius and intramedullary nailing of the ulna.
Open fractures, especially those resulting from gunshot wounds, frequently have associated nerve and major blood vessel involvement. This involvement must be carefully evaluated. Urgent treatment is required for open fractures. A sterile dressing should be placed over the wound, and formal debridement should be reserved for the operating room.
The presence of ipsilateral fractures should be excluded, and a preliminary secondary survey should be performed to rule out other skeletal injuries.
Indications
All displaced adult forearm fractures should be stabilized because no other means of management is available that provides a comparable result. The following are specific indications for operative treatment:
- Fracture of both bones (ie, radius and ulna)
- Fracture dislocations, Monteggia fracture dislocations, and Galeazzi fracture dislocations
- Isolated radius fractures
- Displaced ulnar shaft fractures
- Delayed union or nonunion
- Open fractures
- Fractures associated with a compartment syndrome, irrespective of the extent of displacement
- Multiple fractures in the same extremity, segmental fractures, and floating elbow
- Pathologic fractures
Relevant Anatomy
The radius and ulna function as a unit, but they come into contact with each other only at the ends. They are bound proximally by the capsule of the elbow joint and the annular ligament and distally by the capsule of the wrist joint, the dorsal and volar radioulnar ligaments, and the fibrocartilaginous articular disk. The ulna is relatively straight, has stable articulation with the distal humerus at the elbow, and runs virtually subcutaneously distally to the ulnar styloid at the wrist. The radius is bowed along its length and thus angles at least 13° opposite to the bow to articulate with the capitellum. The radius and ulna form a joint at the distal end, where the strutlike radius sweeps and rotates around the relatively fixed ulna with pronation and supination.
Between the shafts of the radius and ulna is the interosseous space. The fibers of the interosseous membrane run obliquely across the interosseous space from their distal insertion on the ulna to their proximal origin on the radius. The central portion of the interosseous membrane is thickened and is approximately 3.5 cm wide. Hotchkiss et al showed that making an incision on the central band reduces stability by 71%, while making an incision of the triangular fibrocartilage complex and the interosseous membrane proximal to the central band decreases stability by only 11%.3
In the treatment of fractures of the forearm, the radial bow and proper interosseous space must be maintained for normal motion to be achieved. Schemitsch and Richards reported that restoration of the radial bow is related in a linear fashion to the quality of the outcome.4 The normal maximal radial bow, measured from the area between the radius and the ulna across the interosseous membrane, is 15 mm. To achieve 80% of the normal range of movement, this bow must be within 1.5 mm of normal. The same relationship also applies to grip strength. Both the amount and the location of radial bow are crucial correlates to functional outcome.
Contraindications
A medically fit patient has few contraindications to operative fixation of a forearm fracture. Highly contaminated compound fractures, particularly with bone loss, may be managed with temporary external fixation followed by debridement and delayed internal fixation.
More on Forearm Fractures |
 Overview: Forearm Fractures |
| Workup: Forearm Fractures |
| Treatment: Forearm Fractures |
| Follow-up: Forearm Fractures |
| Multimedia: Forearm Fractures |
| References |
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References
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Further Reading
Keywords
forearm fractures, distal-third forearm fractures, middle third forearm fractures, forearm fracture in sports, fractures of the radius and ulna, ulna fracture, radius fracture, radial fracture, ulnar fracture, broken arm, broken ulna, broken radius, broken forearm, fracture of both bones of the forearm, compartment syndrome,
