Radius and Ulnar Shaft Fractures

Etiology

Both bone forearm fractures result from high-energy trauma in young individuals with age-appropriate bone quality. In adults, the common mechanisms that result in bone fractures are motor vehicle accidents, athletic injuries, and falls from height. Both bone forearm fractures that result from low-energy trauma, such as a fall from standing height, are typically only seen in individuals with impaired bone quality.[4]

Epidemiology

Despite the commonality of radius and ulnar shaft fractures, studies that define the epidemiology are scarce. It appears that there is bimodal age distribution with peaks before age 40 and after age 60. Men have similar rates of both bone fractures compared to women early in life. However, women experience a higher proportion of fractures after age 60.[5] High school athletes and active individuals have also been shown to be at-risk populations.[6][7]

Pathophysiology

The most common cause is trauma, typically from an axial load on an outstretched hand or a direct blow to the forearm. In the elderly, forearm fractures are often the result of poor bone quality secondary to osteoporosis. Less commonly, both bone forearm fractures can be an insufficiency fracture due to cancer or other pathologic bone disorders.[8]

History and Physical

Patients generally present with forearm pain after a high-energy mechanism of injury. As with any trauma, the priority is to rule out any life-threatening injuries first. Begin by following the trauma life support protocol, including primary and secondary surveys. Both bone forearm fractures often present with a visible deformity and have significant potential for open fractures. Thus, a thorough examination of the skin surrounding the fracture site should be performed.

Open fractures should be treated with prompt antibiotics, irrigation, and a tetanus booster if needed. The appropriate timing to debridement and closure is a debated topic in the literature. A thorough neurovascular examination of the entire extremity should be performed. The anterior interosseous nerve (AIN), posterior interosseous nerve (PIN), and ulnar nerve distributions should be assessed for motor and sensory deficits. Motor function testing of the AIN can be performed by having the patient perform the ‘a-okay’ sign, the PIN with a ‘thumbs-up,’ and the ulnar nerve with the crossing of the fingers. The radial and ulnar arteries should also be assessed using Doppler if needed. Capillary refill to all digits should be evaluated, monitored, and appropriately documented.

While uncommon, concomitant injuries to the distal radioulnar joint should always be assessed by physical examination and radiographic parameters.[9] The volar and dorsal compartments of the forearm must always be assessed in the setting of an acute both-bone forearm fracture. An analysis of the national trauma database that included over 300,000 adults indicated that 1.22% of forearm fractures required fasciotomy for suspected or confirmed compartment syndrome.[10] Compartment syndrome can also occur in the setting of open fractures. Multiple studies on acute compartment syndrome of the forearm have demonstrated the presence of compartment syndrome in the setting of an open fracture.[11][12] 

Evaluation

Orthogonal radiographs of the forearm should be obtained during the evaluation of both bone forearm fractures. Standard radiographs should include an AP (anterior-posterior) and lateral views of the forearm. Oblique views of the forearm and imaging of the wrist and elbow should be considered as needed. CT scan is rarely required in the setting of both bone forearm fractures but can be useful for complex fractures or if there is a concern for intraarticular involvement.

Treatment / Management

Non-operative treatment of both bone forearm fractures in the pediatric population is common and typically results in a good to excellent outcome.[13] However, non-operative treatment of adult forearm fractures is rarely indicated, and the comparison of non-operative to operative treatment in the literature is scarce.[14] Isolated radial shaft fractures usually require surgical fixation to maintain adequate anatomic alignment and rotation.

Isolated minimal or non-displaced ulnar shaft fractures can be treated nonoperatively with casting or functional bracing, close follow-up, and serial examinations. Because most forearm fractures require surgery, initial reduction and immobilization should be performed with the goal of best preparing the patient for surgery.

For significantly displaced fractures, procedural sedation can be used to properly reduce the fracture and apply a splint. Open fractures should be reduced and thoroughly irrigated, and antibiotics should be started as soon as possible. Standard immobilization is achieved using a sugar-tong splint with the forearm in neutral rotation and the elbow flexed to 90 degrees. Surgical treatment options include open reduction internal fixation (ORIF) and intramedullary nailing. Shorter intraoperative times and decreased scarring are observed benefits following fixation with intramedullary nailing.[15] However, achieving rotational stability as well as restoration of the radial bow is difficult with the use of intramedullary nailing. ORIF with plate and screw construct is generally accepted as the gold standard for treatment.[16] Comparison of ORIF and intramedullary nailing has been inconclusive.[17][18] (A1)

Some studies suggest that a hybrid fixation method of plate fixation of radius and intramedullary nailing of the ulna is a better approach as it shows good stability, fewer complications, and good clinical outcomes.[19] The fracture pattern typically dictates the type of plate and screw construct. Compression plating is often utilized for oblique or transverse fractures to achieve compression at the fracture site and promote primary bone healing. In the setting of long oblique or spiral fracture patterns, interfragmentary screws are utilized to provide compression at the fracture site, and a spanning plate is applied for neutralization.

Finally, bridge plating techniques are utilized for fractures with significant comminution and when interfragmentary compression is unattainable. The goal of any fixation method is to achieve anatomic length, alignment, and rotation across the fracture site. Bone grafting is often utilized if segmental defects are present. However, its effect with regard to fracture union is debated.[20][21] Open fractures are classified using the Gustilo-Anderson classification system. Prompt administration of antibiotics is critical in the management of open fractures. Irrigation and debridement at the time of fixation are indicated for all open fractures. The amount of soft tissue damage may dictate the type of fixation method chosen. For example, Gustilo-Anderson IIIB open fractures with large soft tissue defects may require temporary external fixation prior to definitive fixation and skin coverage.(B2)

Differential Diagnosis

The diagnosis of both bone forearm fractures is relatively straightforward with appropriate imaging. Associated injuries can often be ruled out with imaging of the elbow and wrist, as well as a thorough secondary assessment. Galeazzi and Monteggia fractures should be ruled out with any both-bone forearm fracture. A Galeazzi fracture is described as a distal one-third radial shaft fracture with associated injury to the distal radioulnar joint.[22] A Monteggia fracture is described as a fracture of the proximal one-third of the ulnar shaft with associated dislocation of the radial head. These fracture patterns are more often seen in the pediatric population. Treatment of these fracture variants differs from that of both bone forearm fractures.

Treatment Planning

Treatment planning in both bone forearm fractures depends on many factors. Some of these factors include affected bones, mechanism of the injury, fracture pattern, soft tissue status, demographics, degree of initial displacement, etc. The treatment outcome also depends on the above factors and the accuracy of the reduction with regard to angulation, length, and rotation of the reduced fractures.[23] 

Surgical Approaches for Radius

Henry's Approach

A fair exposure of the whole radius is best provided by the anterior (Henry) approach. The landmark of the incision extends from the bicep tendon to the radial styloid. The incision is made over the fracture site, and dissection is made between the brachioradialis and flexor carpi radialis muscle. The radial nerve and radial artery, which run under the brachioradialis muscle, are retracted. Every effort should be made to maintain the forearm in supination to move the posterior interosseous nerve away from the operative field. For proximal forearm exposure, the supinator muscle is cut medially at the insertion site, and the plate is placed under the reflected part. The forearm is pronated to partially release the pronator teres from insertion. For distal radius exposures, flexor policies longus and pronator quadratus are mobilized from the radius.[24][25]

Thompson Approach

This posterolateral approach is less commonly used due to implant-related complications (tendon injury & implant irritation). The landmark for incision extends from the lateral epicondyle to the Lister's tubercle. The dissection is made between the extensor carpi radialis brevis (ECRB) and extensor digitorum communis (EDC) proximally, while the inter-nervous plane between extensor carpi radialis brevis (ECRB) and extensor pollicis longus (EPL) is used for distal forearm exposure. Similar to the volar approach, supination is maintained to save the posterior interosseous nerve.[26]

Direct Lateral Approach

This approach avoids major neurovascular bundle, which is at risk in both above-mentioned surgical approaches. The incision is made over the mobile wad, and the plane is made between the extensor carpi radialis longus (ECRL) and extensor carpi radialis brevis (ECRB) proximally. The distal direct lateral approach involves an interval between extensor carpi radialis longus (ECRL) and brachioradialis (BR). [27]

Surgical Approach for Ulna

The universal approach for the ulna involves an incision over the shaft of the ulnar border. The dissection is made between the extensor carpi ulnaris and flexor carpi ulnaris muscle. The plate is usually placed over the medial or ulnar surface of the ulna.[28]

Prognosis

The prognosis after both-bone forearm fractures is generally very good. Studies have shown very high rates of union in two months following operative fixation.[29][30] Range of motion exercises of the wrist and elbow are encouraged early following operative fixation, often within one week. Mild decreases in grip strength and range of motion have been observed; however, rates of disability are low.[31][32][33]

Complications

Acute compartment syndrome is a devastating complication of both bone forearm fractures treated with or without surgery. If compartment syndrome is confirmed or suspected, emergent fasciotomy should be performed.[34] Complications following the surgical intervention of both bone forearm fractures include infection, bleeding, non-union, malunion, cross-union, and neurovascular injury. These are minimized by routine surgical safety measures, including medically optimizing the patient before surgery, using standard approaches, and administering antibiotics perioperatively. The use of bone grafting for significantly comminuted or segmental fractures may decrease the risk of non-union.[35]

The risk of radioulnar synostosis has been associated with a single-incision approach.[36] Inadequately treatment and/or reduction of both bone forearm fractures can cause significant loss of motion and function. Malunion particularly limits the pronation-supination movements.[37] Hardware may become bothersome and necessitate removal. There is an increased risk of refracture after plate and screw removal. Initial characteristics of the fracture, early removal, lack of bracing after hardware removal, and characteristics of the plate all appear to influence the risk of refracture.[38] Disruption of the proximal or distal radioulnar joints, as well as the radiocapitellar joint, should be appropriately evaluated for and treated as there are unique complications with these injuries.[36]