What happens if radial head is removed?

Removing the radial head, a procedure known as radial head excision, primarily impacts the stability and function of the elbow joint, particularly in the presence of existing ligamentous injuries.

The Role of the Radial Head

The radial head is the top part of the radius bone, located at the elbow joint. It plays a crucial role in:

• Elbow Stability: It helps to stabilize the elbow against outward (valgus) forces.
• Forearm Rotation: It articulates with the capitellum of the humerus and the ulna, enabling the forearm to rotate (pronation and supination), allowing movements like turning a doorknob or flipping a hand over.
• Load Transmission: It helps transmit forces across the elbow joint.

Consequences of Radial Head Excision

Radial head excision is often performed in cases of severe, complex radial head fractures that cannot be repaired. While it can alleviate immediate pain and restore some motion, its removal carries significant long-term consequences, primarily related to elbow stability and mechanics.

The most critical impact of radial head removal is felt when other structures of the elbow, particularly the ligaments, are also compromised.

• Significant Instability with Ligamentous Injury: If there is pre-existing damage to the elbow's supporting ligaments, such as the medial collateral ligament (MCL) or a combined injury involving both the MCL and the lateral ulnar collateral ligament (LUCL), removing the radial head can lead to profound instability of the elbow joint.
• Valgus Instability: Without the radial head providing a bony block against valgus stress (forces that try to push the forearm outward), and especially if the MCL is damaged, the elbow can become prone to abnormal outward angulation, known as valgus instability. This can result in a feeling of looseness or giving way in the elbow.
• Posterior Elbow Dislocation: In severe cases, particularly with combined MCL and LUCL injuries, the removal of the radial head can contribute to the elbow joint becoming so unstable that it dislocates, where the forearm bones separate from the humerus, often moving posteriorly.
• Altered Biomechanics: The absence of the radial head changes the way forces are distributed across the elbow and wrist. This can lead to:
  • Decreased Grip Strength: The altered mechanics can reduce the efficiency of the forearm muscles, impacting grip strength.
  • Pain: Chronic pain can develop due to abnormal stress on other parts of the joint.
  • Forearm Weakness: Difficulties with movements requiring forearm rotation might arise.
  • Progressive Wrist Pain: Over time, increased stress on the wrist joint (due to altered load transmission through the forearm) can lead to pain and even conditions like ulnar impaction syndrome.

Potential Functional Limitations

Individuals who undergo radial head excision, especially with associated ligamentous damage, may experience a range of functional limitations:

• Difficulty with lifting heavy objects.
• Challenges with activities requiring fine motor control and forearm rotation.
• Chronic discomfort or pain during movement or at rest.
• A feeling of the elbow "giving out" or being unreliable.

Summary of Risks

While radial head excision can be a necessary procedure for certain elbow injuries, its potential for causing significant elbow instability, particularly when ligaments are also damaged, makes it a complex surgical decision. In many cases, if feasible, radial head replacement with a prosthesis is considered to better maintain elbow stability and function.