Radial head fracture

Radial head fractures are a common type of elbow fracture that typically occurs after a fall on an outstretched arm.^[1] They account for approximately one third of all elbow fractures and are frequently associated with other injuries of the elbow.^[2][3] Radial head fractures are diagnosed by a clinical assessment and medical imaging.^[2][4] A radial head fracture is treated according to the severity of the injury and its Mason-Johnston classification. Treatment may be surgical or nonsurgical. Stable isolated fractures typically have excellent outcomes.^[5] Unstable fractures with other associated injuries have varying outcomes. Common adverse outcomes include stiffness, pain, poor bone healing, and hardware complications.^[6]

Radial head fracture
Radial head fracture (red arrow) with posterior and anterior sail sign (blue arrows)
Specialty	Orthopedics
Symptoms	Pain or tenderness over the radial head; bruising; swelling; limited range of motion.
Causes	Fall on an outstretched arm
Diagnostic method	Based on of clinical symptoms and medical imaging
Treatment	Varies according to severity of injury but may include: immobilization followed by range of motion exercises; joint aspiration with mobilization; surgical correction

Signs and symptoms

Symptoms of radial head fractures typically include pain and swelling around the elbow.^[1] The elbow and forearm may have restricted movement.^[1]

Diagnosis and classification

Radial head fractures are diagnosed from a clinical assessment and diagnostic imaging.^[7] Symptoms may include pain or tenderness at the radial head, bruising, swelling, and a limited range of motion of the injured elbow.^[2] Diagnostic imaging may include ultrasound, plain radiography (x-ray imaging), Computed tomography scan (CT), and magnetic resonance imaging (MRI).^[2][4] A fat pad sign may be present on diagnostic imaging and may indicate a radial head fracture.^[5]

A diagnosed radial head fracture can be classified according to the Mason-Johnston system.^[3]

Mason-Johnston Classification of Radial Head Fractures

Type	Description
1	Non-displaced fracture
2	Minimal displacement with angulation or impression (>2mm)
3	Comminuted fracture with dislocation
4	Radial head fracture with dislocation of the elbow

• 
  CT scan showing a radial head fracture
• 
  Radial head fracture seen on 3D CT reconstruction

Treatment

Radial head fracture treatment is informed by the Mason-Johnston classification, patient symptoms, and fracture stability. An unstable fracture will involve fracture displacement, fractures to adjacent structures and injury to other associated soft tissues. A stable type 1 radial head fracture is typically managed with conservative measures including joint aspiration, immobilization in a sling for a few days and followed by early range of motion exercises.^[2][6] If range of motion is still limited after joint aspiration it may indicate a mechanical block which is treated surgically.^[5] Stable type 2 radial head fractures may be treated as a type 1 if the displacement is minimal. Unstable type 2 - 4 fractures generally warrant surgery. Surgical correction can include fracture fragment excision, radial head reconstruction, open reduction and internal fixation, and radial head excision with artificial replacement.^[6] Associated structures that were damaged during the injury may also need to be repaired.

Rehabilitation exercises are recommended and tailored to fracture and treatment type. It is recommended to wait 6 weeks before resuming load bearing with a stable type 1 fracture and 10-12 weeks following surgery for unstable type 2-4 fractures.^[8]

Prognosis and Complications

Stable type 1 and 2 radial head fractures often have good outcomes with most cases regaining complete range of motion and having minimal residual stiffness or pain.^[5] Outcomes for unstable type 2-4 radial head fractures vary greatly depending on the severity of the injury and the surgical intervention.^[5][6] Some of the more common complications of unstable radial head fractures includes stiffness, poor bone healing, nerve damage, and pain/prominent hardware.^[6]