Management of Chronic Ununited Ulnar Styloid Fracture
For chronic symptomatic ulnar styloid nonunions, treatment should be based on distal radioulnar joint (DRUJ) stability: if the DRUJ is stable (Type 1), perform simple excision of the fragment; if the DRUJ is unstable (Type 2), perform either open reduction and internal fixation (ORIF) for large fragments or fragment excision with triangular fibrocartilage complex (TFCC) repair.
Clinical Assessment Algorithm
The critical first step is determining whether the nonunion is symptomatic and whether DRUJ instability is present:
- Assess for ulnar-sided wrist pain during activities and at rest
- Perform DRUJ ballottement test to evaluate stability after examining the contralateral wrist for comparison
- Look for associated TFCC tears - these are commonly present with symptomatic ulnar styloid nonunions 1
- Review imaging for fragment size and location (basilar vs tip fractures)
Classification-Based Treatment
The most clinically useful classification divides nonunions into two types 2:
Type 1: Stable DRUJ
- Treatment: Simple excision of the ulnar styloid fragment
- This provides satisfactory pain relief in all cases 2
- No TFCC repair needed if DRUJ remains stable
Type 2: Unstable DRUJ
Treatment depends on fragment size:
Large fragments (basilar fractures):
- ORIF using angle-stable hook plates (2.0mm distal ulna hook plate) 3, 4
- Achieves 100% union rates 3
- Provides stable fixation with low implant removal risk 4
- Technique: Dorsoradial approach between 6th extensor compartment and flexor carpi ulnaris, reduction with plate hooks, autologous cancellous bone grafting for nonunions 3
Small fragments:
- Fragment excision + TFCC repair to distal ulna 2
- Results: 4 excellent, 1 good, 1 fair outcome in 6 patients 2
Important Diagnostic Considerations
Arthroscopy should be strongly considered in all surgical candidates 1. Key findings include:
- Full-thickness chondral injury on dorsal triquetrum
- Dorsal radiolunotriquetral ligament tears
- TFCC avulsion from extensor carpi ulnaris subsheath
- MRI detects TFCC tears in only 62.5% of cases preoperatively 1
Asymptomatic Nonunions
No treatment is indicated for asymptomatic ulnar styloid nonunions 5, 3. The AAOS guideline explicitly states they are "unable to recommend for or against fixation of ulnar styloid fractures associated with distal radius fractures" due to lack of evidence showing benefit 5.
Critical Pitfalls to Avoid
Do not routinely fix ulnar styloid fractures at the time of distal radius fixation - recent meta-analyses show no functional benefit, higher complication rates (hardware prominence, ulnar-sided pain, paresthesias), and increased implant-related problems despite better union rates 6, 7, 8
Do not assume all nonunions are symptomatic - most are asymptomatic and require no intervention
Do not excise fragments without assessing DRUJ stability - unstable DRUJ requires TFCC repair or ORIF, not simple excision alone
Do not rely solely on MRI - it misses TFCC tears in nearly 40% of cases; consider diagnostic arthroscopy 1
Postoperative Protocol
For surgical cases 3:
- Immobilization in forearm splint for 1-2 weeks
- Active finger motion from postoperative day 1
- Lymphatic drainage as needed
- Progressive loading under occupational therapy guidance after bone healing
Expected Outcomes
Surgical treatment of symptomatic nonunions shows significant improvement 4, 1:
- Mean QuickDASH score: 3.69 postoperatively
- Mean VAS pain score: 1.0 postoperatively
- Statistically significant improvements in grip strength and range of motion
- Mean follow-up: 25 months with no complications requiring implant removal 4