Proximal Radius (Radial Neck) Fractures

Key Points:

  • Radial neck fractures are rare
  • Associated injuries are common and should be ruled-out
  • The most common complication is stiffness or loss of motion
  • Treatment should follow a stepwise approach

Description:

Proximal radius fractures include fractures of the proximal portion of the radius including the radial neck and head.  They are often associated with other injuries including olecranon fractures, elbow dislocations, medial epicondyle fractures and ulna shaft fractures. Understanding the normal ossification pattern of the elbow and proximal radius is essential for correct diagnosis. The radial head ossifies around age 4 years. The unique anatomic features that need to be considered while analyzing these injuries include the normal proximal radial alignment with 15° of valgus and 5° of apex anterior angulation. Due to the annular ligament stabilizing the distal fragment, translation is often seen at fracture site. Excessive translation may block forearm rotation by a cam effect. (Tibone, 1981) While most fractures are metaphyseal, physeal fractures can occur and place the radial head at high risk of avascular necrosis (AVN).

Epidemiology:

The incidence of radial neck fracture is around 1% of all pediatric fractures and between 5-10% of all pediatric elbow fractures. (Basmajian, 2014; Schmittenbecher, 2005; Tibon, 1981; Zimmerman, 2013) Most occur between ages 8 and 12. Around 30-50% are associated with other injuries such as ulna, olecranon and distal humerus fractures, elbow dislocation and collateral ligament injury. (Basmajian, 2014; Schmittenbecher, 2005; Tibon, 1981; Zimmerman, 2013)

Clinical Findings:

There may be elbow swelling and ecchymosis.  Patients will exhibit pain and limited range of motion.  A careful neurovascular examination is important, particularly the assessment of posterior interosseous nerve function.

Imaging Studies:

Typically, radiographs are the only imaging studies required.  Classification is based on plain radiographs.  There are several classifications described, most taking into consideration the amount of displacement (angulation) and translation of the fragment. Proximal/ head fractures are classified according to the Salter-Harris scheme. The presence of associated injuries or dislocation is also noted.

Etiology:

The typical mechanism of injury is a fall over an extended and outstretched arm associated with a valgus force.

Treatment:

The approach to a proximal radial fracture should follow a stepwise approach from closed reduction, to percutaneous assisted reduction, to open treatment. (Basmajian, 2014) The decision is made base on the amount of angulation and translation. (Schmittenbecher, 2005; Zimmerman, 2013) Fractures with less than 30º (45º for younger children) of angulation and < 2-3 mm translation may be treated closed without need for reduction as long as full pronation and supination is present. Fractures with angulation >30º and translation >3mm (>50%) should initially be treated with attempted closed reduction under sedation or anesthesia. If closed reduction is unsuccessful, then percutaneous-assisted reduction should be attempted. This can be performed with direct manipulation of the fragment with a Kirschner wire or Freer elevator. The wire should come from posterior-distal and the forearm should be held in pronation to increase the distance from and protect the posterior interosseous nerve. Another option is the Metaizeau technique which utilizes an elastic nail in a retrograde fashion, engaging the proximal fragment for manipulation and fixation. Irreducible or unstable fractures should be treated with open reduction and internal fixation or open reduction with percutaneous fixation.  Outcomes are influenced by factors including patient age, injury mechanism, fracture characteristics, and treatment approach.  Specifically, a patient age >10 years old is associated with worse prognosis as is increased fracture angulation and translation.  Higher energy injuries and those associated with concomitant elbow injuries are also associated with worse outcomes.  Finally, fractures treated with an open surgical approach have worse prognosis and higher complication rate. (Basmajian, 2014)

Complications:

The most common complications include elbow stiffness and pain. Growth disturbance such as radial head overgrowth or physeal arrest may occur.  Less common complications include avascular necrosis (higher risk after open reduction), posterior interosseous nerve (PIN) injury (either due to trauma or iatrogenic), compartment syndrome, heterotopic ossification, malunion, nonunion, and radioulnar synostosis. (Basmajian, 2014; Zimmerman, 2013)

References:

  1. Basmajian HG, Choi PD, Huh K, Sankar WN, Wells L, Arkader A. Radial neck fractures in children: experience from two level-1 trauma centers. J Pediatr Orthop B. 2014; 23(4): 369-74.
  2. Schmittenbecher PP, Haevernick B, Herold A, Knorr P, Schmid E. Treatment decision, method of osteosynthesis, and outcome in radial neck fractures in children: a multicenter study. J Pediatr Orthop 2005; 25:45–50.
  3. Tibone JE, Stoltz M. Fractures of the radial head and neck in children. J Bone Joint Surg Am. 1981; 63(1): 100-6.
  4. Zimmerman RM, Kalish LA, Hresko MT, Waters PM, Bae DS. Surgical management of pediatric radial neck fractures. J Bone Joint Surg Am. 2013; 95(20): 1825-32.

Top Contributors:

Alexandre Arkader, MD