Radial Head Dislocation: Symptoms, Causes, and Diagnosis

What are the symptoms of a radial head dislocation?

A radial head dislocation, an injury to the elbow joint, typically presents with immediate and severe pain, visible deformity, swelling, and a significant loss of the ability to move the arm, particularly with rotation of the forearm.

Understanding the Radial Head and Elbow Joint

The elbow is a complex hinge joint formed by the articulation of three bones: the humerus (upper arm bone) and the ulna and radius (forearm bones). The radial head is the proximal, disc-shaped end of the radius bone, which articulates with the capitellum of the humerus and the radial notch of the ulna. It plays a crucial role in elbow flexion and extension, as well as forearm pronation (turning the palm down) and supination (turning the palm up). A dislocation occurs when the radial head is forced out of its normal anatomical position, disrupting the joint's integrity.

Causes of Radial Head Dislocation

Radial head dislocations often result from significant trauma, though the specific mechanism can vary:

• Falls onto an outstretched hand (FOOSH): This is a common mechanism, where the force travels up the arm and can disrupt the elbow joint.
• Direct impact to the elbow: A direct blow to the elbow can force the radial head out of alignment.
• Hyper-extension or hyper-flexion injuries: Extreme movements beyond the joint's normal range can lead to dislocation.
• Traction injuries (e.g., Nursemaid's Elbow): While more common in children and involving subluxation rather than full dislocation, strong pulling on the arm can injure the radial head.
• Complex elbow dislocations: Radial head dislocation can be part of a larger, more severe elbow dislocation involving multiple bones and ligaments.

Primary Symptoms of a Radial Head Dislocation

The symptoms of a radial head dislocation are typically immediate and pronounced, reflecting the acute nature of the injury and the disruption to joint mechanics.

• Sudden, Severe Pain:
  • Pain is usually localized to the elbow joint, specifically on the lateral (outer) side where the radial head is located.
  • The pain is often described as sharp, intense, and debilitating, worsening with any attempt to move the arm.
• Visible Deformity or Swelling:
  • The elbow may appear visibly misshapen, with a noticeable bulge or displacement on the outer aspect of the elbow where the radial head has shifted.
  • Rapid onset of swelling around the joint is common due to bleeding and inflammation within the joint capsule.
• Limited Range of Motion:
  • Patients will experience significant difficulty and pain when attempting to bend (flex) or straighten (extend) the elbow.
  • Pronation and Supination Impairment: The most characteristic limitation is often the inability or extreme pain with rotating the forearm (turning the palm up or down), as the radial head's articulation is critical for these movements.
• Tenderness to Palpation:
  • The area directly over the dislocated radial head will be extremely tender to the touch.
• Audible Pop or Click (at time of injury):
  • Many individuals report hearing or feeling a distinct "pop" or "click" at the moment the dislocation occurs, indicative of the bone displacing from its joint.
• Neurological Symptoms (Less Common but Possible):
  • In some cases, the dislocation can compress or stretch nearby nerves (such as the radial nerve), leading to:
    • Numbness or tingling in the forearm or hand.
    • Weakness in the wrist or finger extensors (difficulty lifting the wrist or straightening fingers).

Associated Injuries

It's crucial to understand that a radial head dislocation rarely occurs in isolation. It is frequently accompanied by other injuries that contribute to the overall symptom profile and complexity of the condition:

• Olecranon Fracture: A break in the bony prominence at the back of the elbow (part of the ulna).
• Coronoid Process Fracture: A fracture of the small projection on the ulna that helps stabilize the elbow.
• Ligamentous Injuries: Damage to the collateral ligaments (medial and lateral) that provide stability to the elbow joint.
• Capsular Tears: Tearing of the joint capsule itself.
• Fractures of the Humerus: Less common, but possible in severe trauma.

The presence of these associated injuries can exacerbate pain, swelling, and functional limitations.

When to Seek Medical Attention

Any suspected radial head dislocation requires immediate medical attention. Do not attempt to reduce the dislocation yourself, as this can cause further damage to nerves, blood vessels, or surrounding tissues. Prompt diagnosis and treatment are essential to minimize complications, restore joint function, and prevent long-term issues such as chronic pain, stiffness, or instability.

Diagnosis of Radial Head Dislocation

Diagnosis typically involves:

• Physical Examination: A healthcare professional will assess the elbow for deformity, swelling, tenderness, and range of motion, and check for any neurological deficits.
• X-rays: X-rays are crucial to confirm the dislocation, determine the direction of displacement, and identify any associated fractures.
• CT Scan or MRI: In complex cases or when soft tissue injuries are suspected, a CT scan (for bone detail) or MRI (for ligament and cartilage assessment) may be performed.

Conclusion

A radial head dislocation is a serious injury characterized by acute pain, visible deformity, swelling, and significant loss of elbow and forearm motion. Recognizing these symptoms and seeking immediate medical evaluation are paramount. Early and accurate diagnosis, often involving imaging, is critical for effective treatment and the best possible recovery outcomes.