Is management the same for distal ulnar fractures?

Management of Distal Ulnar Fractures

Management of distal ulnar fractures is not the same as distal radius fractures, and treatment should be guided by the specific characteristics of the ulnar fracture, associated injuries, and patient factors rather than applying the same protocols used for distal radius fractures. 1

Assessment and Classification

• Distal ulnar fractures often occur in conjunction with distal radius fractures but can also present as isolated injuries
• Key radiographic assessment should include:
  • Standard 3-view radiographs to assess fracture pattern and displacement
  • Evaluation of distal radioulnar joint (DRUJ) alignment with a true lateral radiograph 1
  • Assessment of ulnar styloid involvement
  • Evaluation for associated ligamentous injuries

Treatment Approach

Isolated Distal Ulnar Fractures

• Isolated intra-articular fractures of the distal ulna are rare but require careful evaluation 2
• Displaced intra-articular fractures may require internal fixation to prevent:
  • Difficulties in forearm rotation
  • Ulnocarpal impaction
  • Late post-traumatic arthritis

Ulnar Fractures Associated with Distal Radius Fractures

1. Ulnar Styloid Fractures

   • Often associated with distal radius fractures 3
   • Many are asymptomatic even when nonunion occurs
   • Treatment is generally conservative unless there is DRUJ instability

2. Distal Ulnar Shaft/Neck Fractures

   • May require fixation if significantly displaced or causing DRUJ instability
   • Often managed conservatively when minimally displaced

3. Distal Ulnar Physeal Fractures (in children)

   • Higher risk of growth disturbance (50%) compared to distal radial physeal injuries (4.4%) 3
   • Require close monitoring for potential growth arrest

DRUJ Considerations

• DRUJ problems are common after distal forearm fractures 4
• All patients should receive a post-reduction true lateral radiograph to assess DRUJ alignment 1
• DRUJ instability may require specific treatment beyond fracture management
• Symptoms on the ulnar side of the wrist with decreased forearm rotation after healing may indicate DRUJ disorders 4

Complications to Monitor

• Radioulnar length discrepancy
• DRUJ instability or incongruity
• Triangular fibrocartilage complex (TFCC) tears
• Ulnar styloid nonunion (often asymptomatic) 3
• Decreased range of forearm rotation
• Ulnar-sided wrist pain

Post-Treatment Care

• Similar immobilization principles as distal radius fractures (typically 3-4 weeks)
• Home exercise program after immobilization period 1
• Monitor for ulnar-sided wrist pain which may indicate DRUJ pathology

Key Differences from Distal Radius Fracture Management

• Greater focus on DRUJ stability assessment
• Different fixation techniques may be required for ulnar fractures
• Higher risk of growth disturbance in pediatric ulnar physeal fractures
• Management decisions more heavily influenced by DRUJ function rather than just fracture alignment

While the 2022 AAOS/ASSH guidelines provide detailed recommendations for distal radius fractures, they do not specifically address isolated distal ulnar fractures in the same depth 1. Treatment decisions for distal ulnar fractures should focus on preserving DRUJ function and stability rather than simply applying the same protocols used for distal radius fractures.