Prognosis for Ulnar Styloid Fracture
Ulnar styloid fractures have an excellent prognosis with minimal impact on functional outcomes, regardless of whether they heal or progress to nonunion, and the vast majority do not require surgical intervention.
Overall Healing and Functional Outcomes
- Approximately 75% of ulnar styloid fractures remain nonunited at one year, yet this nonunion does not significantly affect patient function or pain levels 1
- The incidence of ulnar styloid fractures accompanying distal radius fractures is approximately 52-55% 2, 1
- Neither the presence, type (tip vs. base), nor union status of an ulnar styloid fracture significantly affects patient-reported outcomes at one year 1
Functional Impact
- Patients with ulnar styloid fractures show no statistically significant difference in DASH scores (6.7 vs 8.4, p=0.47) or PRWE scores (4.8 vs 7.5, p=0.24) compared to those without ulnar styloid fractures at 12 months 1
- Range of motion, grip strength, and functional scores remain similar between patients with united versus nonunited ulnar styloid fractures 2, 3
- Ulnar styloid fractures do not contribute to distal radioulnar joint (DRUJ) instability in the majority of cases 2
Predictors of Nonunion
While nonunion is common, specific factors increase its likelihood:
- Non-base fractures (tip fractures) have significantly higher nonunion rates compared to base fractures 3
- Substantial displacement (≥1.9mm) is a significant predictor of nonunion 3, 4
- AO/OTA C-type distal radius fractures are associated with higher nonunion rates in univariate analysis 3
Important Clinical Caveat
Displaced basilar ulnar styloid fractures involving deep radioulnar ligament attachments may cause DRUJ instability and warrant closer evaluation 5. However, this represents a minority of cases and requires:
- Careful clinical examination for DRUJ instability (ballottement test, piano key sign) 2
- Assessment of ulnar-sided wrist pain that persists beyond expected healing 6
- True lateral radiographs to assess DRUJ alignment 6
Long-term Monitoring
- Patients with persistent ulnar-sided pain during follow-up require reevaluation, as this may indicate complications requiring intervention 6
- Radiographic follow-up at approximately 3 weeks and at time of immobilization removal is appropriate 6
- The majority of ulnar styloid fractures, even when progressing to nonunion, remain asymptomatic and do not require surgical intervention 1, 5
Treatment Implications
- Conservative management is appropriate for the vast majority of ulnar styloid fractures, as surgical fixation does not improve functional outcomes 1, 4
- Temporary DRUJ immobilization may allow triangular fibrocartilage complex (TFCC) recovery 2
- Immediate active finger motion exercises should begin upon diagnosis to prevent stiffness 6