RADIUS AND ULNA SHAFT FRACTURES

EPIDEMIOLOGY

Forearm fractures are more common in men than women, secondary to the higher incidence in men of motor vehicle collisions (MVC) and motorcycle accidents (MCA), contact athletic participation, altercations, and falls from a height.

The ratio of open fractures to closed fractures is higher for the forearm than for any other anatomic area except the tibia.

ANATOMY

The forearm acts as a ring; a fracture that shortens either the radius or the ulna results either in a fracture or a dislocation of the other forearm bone at the proximal or distal radioulnar joint. Direct injuries (“nightstick”) are an exception.

The ulna, which is relatively straight, acts as an axis around which the laterally bowed radius rotates in supination and pronation. A loss of supination and pronation may result from radial shaft fractures in which the lateral curvature (“radial bow”) has not been restored.

The interosseous membrane occupies the space between the radius and ulna. The central band is approximately 3.5-cm wide running obliquely from its proximal origin on the radius to its distal insertion on the ulna. Sectioning of the central band alone reduces stability by 71% (Fig. 21.1).

Fracture location dictates deforming forces:

• Radial fractures distal to the supinator muscle insertion but proximal to the pronator teres insertion tend to result in supination of the proximal fragment owing to unopposed pull of the supinator and biceps brachii muscles.

• Radial fractures distal to the supinator and pronator teres muscles tend to result in neutral rotational alignment of the proximal fragment.

  FRACTURES OF BOTH THE RADIUS AND ULNA SHAFTS

  Mechanism of Injury

These fractures are most commonly associated with high-energy (MVC, MCA) accidents, although they are also commonly caused by direct trauma (while protecting one’s head), gunshot wounds, and falls either from a height or during athletic competition.

Pathologic fractures in this area are uncommon.

Clinical Evaluation

Patients typically present with gross deformity of the involved forearm, pain, swelling, and loss of hand and forearm function.

A careful neurovascular examination is essential, with assessment of radial and ulnar pulses, as well as median, radial, and ulnar nerve function.

One must carefully assess open wounds because the ulna border is subcutaneous, and even superficial wounds can expose the bone.

Excruciating or unremitting pain, tense forearm compartments, or pain on passive stretch of the fingers should raise suspicions of impending or present compartment syndrome. Compartment pressure monitoring should be performed, with urgent fasciotomy indicated for diagnosed compartment syndrome.

Radiographic Evaluation

Anteroposterior (AP) and lateral views of the forearm should be obtained, with oblique views obtained as necessary for further fracture definition.

Radiographic evaluation should include the ipsilateral wrist and elbow to rule out the presence of associated fracture or dislocation (e.g., Monteggia, Galeazzi).

The radial head must be aligned with the capitellum on all views.

Classification

Descriptive

Closed versus open

Location

Comminuted, segmental, multifragmented

Displacement

Angulation

Rotational alignment

Orthopaedic Trauma Association Classification of Fractures of the Radial and Ulna Shaft

See Fracture and Dislocation Compendium at http://ota.org/compendium/index.htm.

Treatment

Nonoperative

The rare, nondisplaced fracture of both the radius and the ulna may be treated with a well-molded, long arm cast in neutral rotation with the elbow flexed to 90 degrees.

The patient should have frequent follow-up to evaluate for possible loss of fracture reduction.

Operative

Because the forearm can be considered a “joint,” responsible for motion, open reduction and internal fixation is the procedure of choice for displaced forearm fractures involving the radius and ulna in adults.

Patient positioning is supine with the extremity on a radiolucent hand table.

An anterior (volar, Henry approach) or posterior (dorsal, Thompson) approach may be used for

radius shaft fixation. The advantage of a posterior approach is that it allows for the identification of the posterior interosseous nerve (PIN) in the supinator for proximal radius fractures. The anterior approach is advantageous for fractures which extend into the distal metaphysis.

Internal fixation involves use of compression plating (3.5-mm dynamic compression [DC] plate) with or without bone grafting.

Principles of plate fixation:

• Restore ulnar and radial length (prevents subluxation of either the proximal or distal radioulnar joint).

• Restore rotational alignment.

• Restore radial bow (essential for rotational function of the forearm).

The ulna may be plated on either the volar or dorsal aspect, depending on the location of the fragments and contour of the ulna surrounding the fracture site. Using two separate incisions decreases the incidence of radioulnar synostosis.

One should consider acute grafting if substantial comminution or bone loss exists.

Use of bridge plating for comminuted fractures, with minimization of soft tissue disruption, may reduce the need for acute bone grafting.

Open fractures may receive primary open reduction and internal fixation after debridement, except in severe open injuries. This approach restores stability, limits dead space, and improves wound care. The timing of bone grafting of open fractures is controversial; it can be performed at the time of delayed primary closure or at 6 weeks after injury.

External fixation may be used in cases with severe bone or soft tissue loss, gross contamination, infected nonunion, or in cases of open elbow fracture-dislocations with soft tissue loss.

Good results have been reported with locked intramedullary nail fixation. However, the indications for intramedullary nailing over plate and screws have not been clearly defined. This procedure is technically more demanding. Some of the reported indications are segmental fractures, open fractures with bone or soft tissue loss, pathologic fractures, and failed plate fixation.

Complications

Nonunion and malunion: These are uncommon, most often related to infection and errors of surgical technique. Patients may require removal of hardware, bone grafting, and revision internal fixation.

Infection: The incidence is only 3% with open reduction and internal fixation. It necessitates surgical drainage, debridement, copious irrigation, wound cultures, and antibiotics. If internal fixation is found to be stable, it does not necessarily need to be removed because most fractures will unite despite infection. Unresponsive infections with severe soft tissue and osseous compromise may necessitate external fixation with wounds left open and serial debridements.

Neurovascular injury: This is uncommon, associated with gunshot injury or iatrogenic causes. Nerve palsies can generally be observed for 3 months, with surgical exploration indicated for failure of return of nerve function. Injuries to the radial or ulnar arteries may be addressed with

simple ligation if the other vessel is patent.

Compartment syndrome: This has been reported to occur in 10% of forearm fractures secondary to gunshot injury, usually in the proximal third of the forearm.

Volkmann contracture: This devastating complication follows a missed compartment syndrome. Clinical suspicion should be followed by compartment pressure monitoring with emergency fasciotomy if a compartment syndrome is diagnosed.

Posttraumatic radioulnar synostosis: This is uncommon (3% to 9% incidence); the risk increases with massive crush injuries or closed head injury. It may necessitate surgical excision if functional limitations of supination and pronation result, although a nonarticular synostosis excision is rarely successful in the proximal forearm. Separate incisions for bony fixation are best for avoiding this complication.

Risk factors include:

• Fracture of both bones at the same level (11% incidence)

• Closed head injury

• Surgical delay >2 weeks

• Single incision for fixation of both bone forearm fractures

• Penetration of the interosseous membrane by bone graft or screws, bone fragments, or surgical instruments

• Crush injury

• Infection

   

  FRACTURES OF THE ULNA SHAFT

These include nightstick and Monteggia fractures, as well as stress fractures in athletes.

A Monteggia lesion denotes a fracture of the proximal ulna accompanied by radial head dislocation.

Mechanism of Injury

Ulna nightstick fractures result from direct trauma to the ulna along its subcutaneous border, classically as a victim attempts to protect the head from assault.

Monteggia fractures are produced by various mechanisms (by Bado classification) (Fig. 21.2):

Type I: Forced pronation of the forearm

Type II: Axial loading of the forearm with a flexed elbow

Type III: Forced abduction of the elbow

Type IV: Type I mechanism in which the radial shaft additionally fails

Clinical Evaluation

Patients with a nightstick fracture typically present with focal swelling, pain, tenderness, and variable abrasions at the site of trauma.

Patients with Monteggia fractures present with elbow swelling, deformity, crepitus, and painful range of elbow motion, especially supination, and pronation.

A careful neurovascular examination is essential, because nerve injury, especially to the radial nerve or PIN, is common. Most nerve injuries have been described with type II Bado fractures.

Radiographic Evaluation

AP and lateral views of the forearm (additional views should include the wrist and elbow) are required.

Oblique views may aid in fracture definition.

Normal radiographic findings:

• A line drawn through the radial head and shaft should always line up with the capitellum.

• Supinated lateral: Lines drawn tangential to the radial head anteriorly and posteriorly should enclose the capitellum.

  Classification of Ulna Fractures

  Descriptive

Closed versus open

Location

Comminuted, segmental, multifragmented

Displacement

Angulation

Rotational alignment

Bado Classification of Monteggia Fractures (Fig. 21.2)

Type I: Anterior dislocation of the radial head with fracture of ulnar diaphysis at any level with anterior angulation

Type II: Posterior/posterolateral dislocation of the radial head with fracture of ulnar diaphysis with posterior angulation

Type III: Lateral/anterolateral dislocation of the radial head with fracture of ulnar metaphysis

Type IV: Anterior dislocation of the radial head with fractures of both radius and ulna within proximal third at the same level

Classification

Orthopaedic Trauma Association Classification of Fractures of the Ulna Shaft

See Fracture and Dislocation Compendium at http://ota.org/compendium/index.htm.

Treatment

Nightstick Fractures

Nondisplaced or minimally displaced ulna fractures may be treated with plaster immobilization in a sugar-tong splint for 7 to 10 days. Depending on the patient’s symptoms, this may be followed by functional bracing for 8 weeks with active range-of-motion exercises for the elbow, wrist, and hand, or simple immobilization in a sling with a compression wrap.

Displaced fractures (>10-degree angulation in any plane or >50% displacement of the shaft) should be treated with open reduction and internal fixation using a 3.5-mm DC plate.

Monteggia Fractures

Closed reduction and casting of Monteggia fractures should be reserved only for the pediatric population.

Monteggia fractures require operative treatment, open reduction, and internal fixation of the ulna shaft with a 3.5-mm DC plate or reconstruction plate. Closed reduction of the radial head with restoration of ulnar length is the rule. Plate application on the tension side (dorsal) is recommended especially in Bado type II fracture.

After fixation of the ulna, the radial head is usually stable (>90%).

Failure of the radial head to reduce with ulna reduction and stabilization is usually the result of inaccurate reduction of the ulna. Secondarily, an interposed annular ligament or, rarely, the radial

nerve or PIN can be the cause.

Associated radial head fractures may require fixation or replacement.

Postoperatively, the patient is placed in a posterior elbow splint for 5 to 7 days. With stable fixation, physical therapy can be started with active flexion–extension and supination–pronation exercises. If fixation or radial head stability is questionable, the patient may be placed in longer term immobilization with serial radiographic evaluation to determine healing, followed by a supervised physical therapy regimen.

Complications

Nonunion: It is seen most often with Bado type II fractures.

Nerve injury: It is most commonly associated with Bado types II and III injuries involving the radial and/or median nerves, as well as their respective terminal branches, the posterior and anterior interosseous nerves. These may also complicate open reduction owing to overzealous traction or reduction maneuvers. Surgical exploration is indicated for failure of nerve palsy recovery after a 3-month period of observation.

Radial head instability: This is uncommon following anatomic reduction of the ulna. If redislocation occurs <6 weeks postoperatively with a nonanatomic reduction of the ulna, repeat reduction and fixation of the ulna with an open reduction of the radial head may be considered. Dislocation of the radial head >6 weeks postoperatively is best managed by radial head excision.

FRACTURES OF THE RADIAL SHAFT

Fractures of the proximal two-thirds of the radius without associated injuries may be considered to be truly isolated. However, radial fractures involving the distal third involve the distal radioulnar joint until proven otherwise.

A Galeazzi refers to a fracture of the radial diaphysis at the junction of the middle and distal thirds with associated disruption of the distal radioulnar joint. It has also been referred to as the “fracture of necessity,” because it requires open reduction and internal fixation to achieve a good result. This lesion is approximately three times as common as Monteggia fractures.

• Variants: Fracture can occur anywhere along the radius or associated with fractures of both radius and ulna with distal radioulnar joint disruption.

Four major deforming forces contribute to a loss of reduction if the fracture is treated by

nonoperative means:

1. Weight of the hand: This results in dorsal angulation of the fracture and subluxation of the distal radioulnar joint.

2. Pronator quadratus insertion: This tends to pronate the distal fragment with proximal and volar displacement.

3. Brachioradialis: This tends to cause proximal displacement and shortening.

4. Thumb extensors and abductors: These result in shortening and relaxation of the radial collateral ligament, allowing displacement of the fracture despite immobilization of the wrist in ulnar deviation.

A reverse Galeazzi fracture denotes a fracture of the distal ulna with associated disruption of the distal radioulnar joint.

Mechanism of Injury

Radial diaphyseal fractures may be caused by direct trauma or indirect trauma, such as a fall onto an outstretched hand.

The radial shaft in the proximal two-thirds is well padded by the extensor musculature; therefore, most injuries severe enough to result in proximal radial shaft fractures typically result in ulna fracture as well. In addition, the anatomic position of the radius in most functional activities renders it less vulnerable to direct trauma than the ulna.

Galeazzi fractures may result from direct trauma to the wrist, typically on the dorsolateral aspect, or a fall onto an outstretched hand with forearm pronation.

Reverse Galeazzi fractures may result from a fall onto an outstretched hand with forearm supination.

Clinical Evaluation

Patient presentation is variable and is related to the severity of the injury and the degree of fracture displacement. Pain, swelling, and point tenderness over the fracture site are typically present.

Elbow range of motion, including supination and pronation, should be assessed; rarely, limited forearm rotation may suggest a radial head dislocation in addition to the diaphyseal fracture.

Galeazzi fractures typically present with wrist pain or midline forearm pain that is exacerbated by stressing of the distal radioulnar joint in addition to the radial shaft fracture.

Neurovascular injury is rare.

Radiographic Evaluation

AP and lateral radiographs of the forearm, elbow, and wrist should be obtained.

Radiographic signs of distal radioulnar joint injury are:

• Fracture at base of the ulnar styloid

• Widened distal radioulnar joint on AP x-ray

• Subluxed ulna on lateral x-ray

• >5-mm radial shortening

   

  Classification

  Orthopaedic Trauma Association Classification of Fractures of the Radial Shaft

  See Fracture and Dislocation Compendium at http://ota.org/compendium/index.htm.

  Treatment

  Proximal Radius Fracture

Nondisplaced fractures may be managed in a long arm cast. Any evidence of loss of radial bow is

an indication for open reduction and internal fixation. The cast is continued until radiographic evidence of healing occurs.

Displaced fractures are best managed by open reduction and plate fixation using a 3.5-mm DC plate.

Galeazzi Fractures

Open reduction and internal fixation comprise the treatment of choice, because closed treatment is associated with a high failure rate.

Plate and screw fixation (3.5-mm DC plating) is the treatment of choice.

An anterior Henry approach (interval between the flexor carpi radialis and the brachioradialis) typically provides adequate exposure of the radius fracture, with plate fixation on the flat, volar surface of the radius.

The distal radioulnar joint injury typically results in dorsal instability; therefore, a dorsal capsulotomy may be utilized to gain access to the distal radioulnar joint if it remains dislocated after fixation of the radius. Kirschner wire fixation may be necessary to maintain reduction of the distal radioulnar joint if unstable. If the distal radioulnar joint is believed to be stable, however, postoperative plaster immobilization may suffice.

Postoperative management:

• If the distal radioulnar joint is stable: Early motion is recommended.

• If the distal radioulnar joint is unstable: Immobilize the forearm in supination for 4 to 6 weeks in a long arm splint or cast.

• Distal radioulnar joint pins, if needed, are removed at 6 to 8 weeks.

   

  Complications

Malunion: Nonanatomic reduction of the radius fracture with a failure to restore rotational alignment or lateral bow may result in a loss of supination and pronation, as well as painful range of motion. This may require osteotomy or distal ulnar shortening for cases in which symptomatic shortening of the radius results in ulnocarpal impaction.

Nonunion: This is uncommon with stable fixation, but it may require bone grafting.

Compartment syndrome: Clinical suspicion should be followed by compartment pressure monitoring with emergency fasciotomy if a compartment syndrome is diagnosed.

• One should assess all three forearm compartments and the carpal tunnel.

Neurovascular injury:

• This is usually iatrogenic.

• Superficial radial nerve injury (beneath the brachioradialis) is at risk with anterior radius approaches.

• PIN injury (in the supinator) is at risk with proximal radius approaches.

• If no recovery occurs, explore the nerve at 3 months.

Radioulnar synostosis: This is uncommon (3% to 9% incidence).

• See previous discussion.

• The worst prognosis is with distal synostosis, and the best is with diaphyseal synostosis.

Neurovascular injury: This is uncommon, associated with gunshot injury or iatrogenic need for anatomic restoration of the radial fracture to ensure adequate healing and biomechanical function of the distal radioulnar joint.

Refracture: Reported to be as high as 30% after plate removal. One should wait at least 1 year after surgery before plate removal.