What is the evaluation and management approach for chronic radial head dislocation?

Evaluation and Management of Chronic Radial Head Dislocation

Initial Diagnostic Evaluation

Obtain CT without contrast to fully characterize the injury pattern, identify associated fractures (particularly coronoid fractures which are commonly missed on plain radiographs), and assess the current state of the radiocapitellar relationship. 1

Key Imaging Studies

• Plain radiographs should include anteroposterior views in internal and external rotation plus an axillary or scapula-Y view to assess radiocapitellar alignment and identify any healed fractures 2
• CT without contrast is essential because it identifies coronoid process fractures that indicate severe instability and are frequently missed on radiographs alone 1
• MRI without contrast should be obtained to assess the current state of the lateral collateral ligament complex, medial collateral ligament, capsule, and any associated tendinous injuries 3
• Stress fluoroscopy can quantify the degree of instability: <10° widening indicates slight instability, >10° widening indicates moderate instability, and frank redislocation indicates gross instability—this directly impacts surgical planning 3

Critical Radiographic Features to Assess

• Shape of the radial head articular surface: A normal concave proximal radial articular surface is the primary criterion for surgical candidacy 4
• Ulnar and radial alignment: Look for any deformity of the ulna or radius that would require corrective osteotomy 4, 5
• Lateral joint space widening: Increased gap between radial head and lateral condyle on stress views demonstrates lateral ligamentous insufficiency 3
• Associated coronoid fractures: These are sequelae of prior elbow dislocation and indicate undertreated soft tissue ligamentous injuries 3

Management Approach

Surgical Indications

Surgery is indicated for patients with incapacitating symptoms who have a normal concave radial head articular surface, regardless of patient age or duration of dislocation. 4

The key surgical criteria are:

• Normal concave radial head articular surface 4
• Normal shape and contour of the ulna and radius (any deformity should be corrected by osteotomy) 4
• Patient age and duration of dislocation are unimportant factors 4

Surgical Technique

The optimal surgical approach combines open reduction of the radial head with oblique ulnar osteotomy (with both angulation and elongation) and annular ligament reconstruction, using rigid plate fixation. 5, 6

Specific Technical Components:

• Oblique ulnar osteotomy with angulation and elongation is the key to achieving good reduction—both angulation and elongation are required to allow the radial head to reduce properly 5
• Rigid plate fixation at the osteotomy site 5
• Bone grafting at the osteotomy site if necessary 5
• Annular ligament reconstruction using two drill holes in the proximal ulna placed at the original attachments of the annular ligament, which can be repaired (if avulsed) or reconstructed using triceps tendon 4
• Radial osteotomy may be added if radial deformity is present 5

Postoperative Management

• Immobilization: Apply cast with forearm in neutral rotation for 2-4 weeks 5
• Early mobilization: Initiate active finger motion exercises immediately to prevent hand stiffness, which is a functionally disabling complication 1
• Expected return to function: Patients typically return to work approximately 5 months after surgery 7

Expected Outcomes

Studies using the modified oblique osteotomy technique report good reduction in 7 of 9 patients (78%), with only 2 patients experiencing subluxation (both had slight radial head deformity preoperatively) 5. Patients with successful reduction achieve full range of motion in all planes by one year postoperatively 7. The most common complication is loss of pronation 8.

Prognostic Factors

Severe motion restriction combined with instability portends a challenging reconstruction with guarded prognosis, as patients with moderate instability and prolonged immobilization demonstrate significantly worse Mayo Elbow Performance Scores. 3

The degree of preoperative carrying angle asymmetry associated with flexion contracture correlates significantly with final elbow scores 8.

Critical Pitfalls to Avoid

• Do not miss coronoid fractures—they indicate severe instability and require CT imaging for identification 1
• Do not perform reduction without correcting ulnar malalignment—correction of malalignment with ulnar osteotomy is the key to preventing redislocation 5
• Do not operate on patients with deformed radial heads—slight radial head deformity preoperatively predicts postoperative subluxation 5