What is the treatment for a non-displaced avulsion fracture involving the ulnar styloid process?

Treatment of Non-Displaced Avulsion Fracture Involving the Ulnar Styloid Process

Non-displaced ulnar styloid avulsion fractures generally do not require surgical fixation and can be effectively managed with conservative treatment including immobilization and symptomatic care.1

Initial Assessment and Classification

• Ulnar styloid fractures occur in approximately 55% of all distal radius fractures2
• Key evaluation points:
  • Determine stability of distal radioulnar joint (DRUJ)
  • Assess for displacement (>3mm suggests potential instability)
  • Identify fracture location (tip vs. base)
  • Rule out associated injuries

Treatment Algorithm

Conservative Management (First-Line)

1. Immobilization:

   • Rigid immobilization with cast is preferred for 3-6 weeks1, 3
   • Short arm cast with wrist in neutral position
   • Alternative: Removable splint for minimally displaced fractures3

2. Pain Management:

   • NSAIDs for pain control
   • Ice application during first 3-5 days can provide symptomatic relief1

3. Follow-up:

   • Radiographic follow-up at 3 weeks and at cessation of immobilization3
   • Assess for signs of union and DRUJ stability

Rehabilitation

• Active finger motion exercises should begin immediately following diagnosis to prevent stiffness1
• After immobilization period: progressive range of motion exercises and gradual return to activities

Special Considerations

When to Consider Surgical Intervention

While most non-displaced ulnar styloid fractures heal well with conservative treatment, surgical fixation might be considered in specific situations:

• DRUJ instability despite adequate immobilization
• Large, displaced base fractures involving >50% of the styloid
• Failed conservative management with persistent symptoms

The American Academy of Orthopaedic Surgeons (AAOS) states: "We are unable to recommend for or against fixation of ulnar styloid fractures associated with distal radius fractures."1 This reflects the lack of strong evidence supporting routine surgical fixation of these fractures.

Long-Term Outcomes

Research shows that non-union of ulnar styloid fractures is common but typically does not affect functional outcomes:

• A 2023 study found no significant difference in range of movement, grip strength, or functional scores (DASH) between patients with united versus non-united ulnar styloid fractures2
• The site of fracture (tip or base) did not influence functional outcomes2

Potential Complications

• Non-union (common but often asymptomatic)
• DRUJ instability (rare with non-displaced fractures)
• Ulnar-sided wrist pain
• Triangular fibrocartilage complex (TFCC) injury

Treatment of Symptomatic Non-Union

If symptomatic non-union develops (uncommon with non-displaced fractures):

• Type 1 (stable DRUJ): Simple excision of the ulnar styloid fragment4
• Type 2 (unstable DRUJ): Restoration of TFCC anatomy, either through fragment fixation or excision with TFCC repair4

The evidence strongly suggests that most non-displaced ulnar styloid fractures can be successfully managed with conservative treatment, and surgical intervention should be reserved for specific cases with DRUJ instability or persistent symptoms despite adequate conservative management.