Treatment of Ulnar Styloid Fractures
Ulnar styloid fractures associated with distal radius fractures do not require surgical fixation when the distal radioulnar joint (DRUJ) is stable after radius fixation, and conservative management with immobilization provides equivalent long-term outcomes to surgical treatment. 1, 2, 3
Initial Assessment
Determine DRUJ stability - this is the critical decision point that guides all subsequent management:
- Perform intraoperative ballottement testing after distal radius fixation to assess DRUJ stability 3
- Obtain radiographs with at least 3 views (posteroanterior, lateral, and 45° semipronated oblique) to characterize the fracture 1, 4
- Classify the fracture location: tip versus base fractures (base fractures have higher rates of TFCC tears and DRUJ instability) 5
Treatment Algorithm Based on DRUJ Stability
For Stable DRUJ (Most Common Scenario)
Conservative management is sufficient regardless of fracture characteristics:
- No surgical fixation is needed even for base fractures or displaced fractures when DRUJ is stable 2, 3, 6
- Apply rigid immobilization (casting preferred over removable splints for displaced fractures) 1
- Supination sugar-tong splinting for average 6.6 weeks (range 4-9 weeks) provides equivalent outcomes to surgical treatment 3
- The presence, location (tip vs base), degree of displacement, or eventual union status does not affect patient-rated outcomes at 1 year 2, 6
Key evidence supporting conservative management:
- A prospective study of 134 surgically treated distal radius fractures found 52% had associated ulnar styloid fractures, with 76% remaining nonunited at 1 year, yet there was no statistical difference in QDASH scores (6.7 vs 8.4, p=0.47) or PRWE scores (4.8 vs 7.5, p=0.24) between patients with and without ulnar styloid fractures 2
- A randomized trial comparing conservative versus operative treatment found similar long-term flexion-extension ranges (122±25° vs 119±18° vs 120±16°) and modified Mayo wrist scores (87±7 vs 89±8 vs 85±9) regardless of treatment method 3
For Unstable DRUJ (Uncommon)
Surgical fixation is indicated:
- DRUJ instability after radius fixation requires treatment of the ulnar styloid fracture 3, 5
- Base fractures with DRUJ instability have higher incidence of TFCC tears requiring intervention 5
- Angle-stable hook plate fixation achieves 100% bony healing in surgical series 7
Timing Considerations
Non-urgent management is appropriate for closed fractures:
- Surgical intervention within 48 hours is not mandatory for closed distal ulna fractures without neurovascular compromise 1
- Delayed casting within a few days does not negatively impact outcomes for stable fractures 1
- Initial management with appropriate splinting and pain control while awaiting orthopedic evaluation is acceptable 1
Immediate intervention (within 24 hours) is required only for:
- Open fractures requiring debridement and antibiotics 1
- Vascular injury or mangled extremity 1
- Compartment syndrome 1
- Severe soft tissue compromise 1
Common Pitfalls to Avoid
Do not routinely fix ulnar styloid fractures based solely on radiographic appearance:
- The degree of pre-operative displacement predicts nonunion risk but does not mandate surgical treatment in the absence of DRUJ instability 5
- Even large base fractures with significant displacement do not require fixation if DRUJ is stable 2, 6
- Nonunion of ulnar styloid fractures, while common (occurring in 76% of cases), does not correlate with worse functional outcomes when DRUJ is stable 2
Recognize that associated ulnar styloid fractures may not require separate fixation when managing distal radius fractures:
- Studies show no significant difference in outcomes between treatment and non-treatment of ulnar styloid fractures when the radius fracture is properly managed 4
- Guidelines are inconclusive regarding fixation of ulnar styloid fractures associated with distal radius fractures 1