Chronic Radial Head Dislocation: Surgical Treatments, Recovery, and Prognosis

What is the surgical treatment for chronic radial head dislocation?

Surgical intervention for chronic radial head dislocation aims to restore anatomical alignment, stabilize the radio-ulnar joint, and preserve elbow and forearm function, often involving complex procedures such as open reduction, annular ligament reconstruction, and osteotomies to address long-standing deformities and instability.

Understanding Chronic Radial Head Dislocation

Chronic radial head dislocation refers to a long-standing displacement of the radial head from its normal articulation with the capitellum of the humerus and the ulna. Unlike acute dislocations, which occur suddenly, chronic dislocations have often been present for weeks, months, or even years, leading to adaptive changes in the surrounding soft tissues (ligaments, joint capsule) and bony structures.

Common causes include:

• Monteggia Fracture-Dislocation: A fracture of the ulna associated with dislocation of the radial head. If untreated or improperly managed, the radial head dislocation can become chronic.
• Congenital Conditions: Such as isolated congenital radial head dislocation or syndromic conditions like multiple hereditary exostoses.
• Traumatic Injuries: Severe elbow trauma that disrupts the annular ligament and other stabilizing structures, leading to persistent instability.
• Ligamentous Laxity: General joint hypermobility or specific laxity of the elbow ligaments.

Due to the adaptive changes in the joint and surrounding tissues, manual reduction (non-surgical) is typically ineffective for chronic dislocations. The deformed tissues and bone changes often prevent stable relocation, necessitating surgical intervention.

Goals of Surgical Intervention

The primary objectives of surgically treating chronic radial head dislocation are multifaceted and aim to restore optimal elbow and forearm mechanics:

• Anatomical Reduction: Re-establishing the correct alignment of the radial head within the capitellum and proximal ulna.
• Joint Stability: Reconstructing or repairing the annular ligament and other soft tissue stabilizers to prevent re-dislocation.
• Pain Alleviation: Reducing discomfort caused by abnormal joint mechanics or impingement.
• Functional Restoration: Improving range of motion, strength, and the ability to perform daily activities, including pronation and supination of the forearm.
• Prevention of Degenerative Changes: Minimizing the long-term risk of osteoarthritis in the elbow joint.

Factors Influencing Surgical Decision

The choice of surgical procedure is highly individualized and depends on several critical factors:

• Patient Age: Younger patients, especially those with significant growth potential, may benefit from procedures that preserve the radial head. In older patients with degenerative changes, radial head excision or replacement might be considered.
• Etiology of Dislocation: Whether the dislocation is congenital, traumatic, or associated with a specific syndrome influences the approach.
• Duration of Dislocation: Longer-standing dislocations often involve more significant soft tissue contractures and bony deformities, requiring more complex procedures.
• Associated Injuries: The presence of an ulnar fracture (as in Monteggia) or other elbow injuries dictates the need for combined procedures.
• Degree of Deformity: The extent of radial head malformation or the presence of bony blocks to reduction.
• Surgeon's Experience: The specific techniques available and the surgeon's expertise in complex elbow reconstruction.

Common Surgical Procedures for Chronic Radial Head Dislocation

Surgical treatment often involves a combination of techniques, tailored to the individual patient's pathology.

• Open Reduction of the Radial Head:

  • This involves surgically exposing the dislocated radial head and manually repositioning it back into its correct anatomical location.
  • Often, soft tissue releases (e.g., of the biceps tendon, brachialis muscle) are required to overcome chronic contractures that prevent reduction.
  • In cases of Monteggia fracture-dislocation, the ulnar fracture is first stabilized, which indirectly aids in reducing the radial head.

• Annular Ligament Reconstruction or Repair:

  • The annular ligament is crucial for stabilizing the radial head. In chronic dislocations, it is often torn, attenuated, or displaced.
  • Direct Repair: If the ligament tissue is adequate, it can be directly repaired.
  • Reconstruction: More commonly, the ligament needs to be reconstructed using a tendon graft (e.g., palmaris longus, gracilis, or triceps fascia). The graft is passed around the radial neck and secured to the ulna, mimicking the native annular ligament.

• Osteotomies:

  • Ulnar Osteotomy: In Monteggia fracture-dislocations, a corrective osteotomy of the ulna (cutting and re-aligning the bone) may be necessary to restore proper length and angulation, which in turn helps to reduce and stabilize the radial head.
  • Radial Osteotomy: Less common, but may be used to correct significant deformities of the radial neck or shaft that impede reduction or function.

• Radial Head Excision (Resection Arthroplasty):

  • This procedure involves surgically removing the radial head.
  • Indications: Often considered in older patients with irreducible, painful dislocations, or those with significant degenerative changes who do not require a stable forearm axis for weight-bearing activities. It is also an option when other reconstructive efforts fail.
  • Considerations: While it can relieve pain and improve some motion, it may lead to proximal migration of the radius, altered load distribution across the elbow, and potential wrist pain in the long term.

• Radial Head Arthroplasty (Replacement):

  • Involves replacing the resected radial head with a prosthetic implant (metal or pyrocarbon).
  • Indications: Used when radial head excision is not desirable (e.g., younger, active patients, or when stability of the forearm axis is critical, such as in certain trauma cases or for preventing proximal migration).
  • Considerations: Provides joint stability and improved load bearing compared to simple excision, but carries risks associated with implant loosening, wear, or infection.

• Bone Grafting:

  • If chronic dislocation has led to bone loss or significant defects, bone grafts (autograft from the patient or allograft from a donor) may be used to fill voids and provide structural support.

Post-Operative Rehabilitation and Recovery

Post-surgical care is critical for optimal outcomes and typically follows a structured rehabilitation protocol:

• Immobilization: The elbow is usually immobilized in a cast or brace for a period (e.g., 3-6 weeks) to protect the surgical repair and allow initial healing.
• Gradual Range of Motion: Following immobilization, a physical therapy program begins with gentle, progressive range-of-motion exercises to prevent stiffness and regain elbow and forearm movement.
• Strengthening: As healing progresses, strengthening exercises for the elbow and surrounding musculature are introduced.
• Return to Activity: A gradual return to daily activities and sports is guided by the surgeon and physical therapist, typically over several months. Full recovery can take 6-12 months or longer.

Prognosis and Potential Complications

The prognosis for surgical treatment of chronic radial head dislocation varies widely depending on the underlying cause, the extent of the deformity, and the specific procedures performed.

• Outcomes: Many patients experience significant pain relief and improved elbow function. However, complete restoration of normal motion and strength may not always be achieved. Some residual stiffness, pain, or limited range of motion is possible.
• Potential Complications: As with any major surgery, risks include infection, nerve damage, blood vessel injury, re-dislocation, persistent pain, stiffness, heterotopic ossification (abnormal bone growth), and implant-related issues if an arthroplasty was performed.

Surgical treatment for chronic radial head dislocation is a complex reconstructive endeavor that requires careful planning and a dedicated rehabilitation effort to achieve the best possible functional outcomes.