What is the appropriate management for a triquetral avulsion fracture?

Management of Triquetral Avulsion Fractures

For triquetral avulsion fractures, immobilize in a short-arm cast for 3 weeks, which is the standard conservative treatment for these injuries 1.

Diagnostic Approach

When evaluating suspected triquetral avulsion fractures:

• Initial imaging should be standard 3-view wrist radiographs (PA, lateral, and 45° semipronated oblique) 2
• The lateral view is critical as dorsal avulsion fractures are often missed on frontal views alone 1
• If radiographs are equivocal but clinical suspicion remains high, obtain CT without IV contrast to confirm the diagnosis 2

Critical Distinction: Dorsal vs. Volar Fractures

The location of the avulsion determines both prognosis and management:

Dorsal avulsion fractures (93% of cases):

• Most common type, typically benign 1
• Result from either ligamentous avulsion or impaction by the ulnar styloid 1
• Present with localized dorsal tenderness over the triquetrum 1
• Treat conservatively with 3 weeks of short-arm cast immobilization 1
• Residual symptoms may persist for several months but are not uncommon 1

Volar avulsion fractures (rare but problematic):

• These are high-risk injuries that require additional workup 3
• Involve the radial aspect of the volar triquetral surface 3
• Strongly associated with lunotriquetral ligament tears and carpal instability 3
• Obtain MRI to evaluate for ligamentous injury 1
• Consider wrist arthroscopy as the gold standard to confirm LT ligament rupture, followed by transfixation of the LT joint 1
• All five patients in one series had persistent pain and instability at 1 year despite treatment 3

Treatment Algorithm

1. Purely osseous dorsal avulsion: Short-arm cast for 3 weeks 1
2. Volar avulsion or body fractures:
   • Obtain MRI to assess ligamentous structures 1
   • Consider arthroscopy if instability suspected 1
   • May require surgical intervention for significant displacement or instability 4

Common Pitfalls

• Volar avulsions are easily missed on standard radiographs and were not recognized in the emergency room in any of the five cases in one series 3
• Do not assume all triquetral avulsions are benign—volar fractures indicate significant perilunate ligament injury 3
• When a volar avulsion is identified, further evaluation for carpal instability is mandatory 3

Expected Outcomes

For standard dorsal avulsion fractures treated conservatively, outcomes are generally good 4. However, patients should be counseled that residual symptoms may persist for several months 1. In contrast, volar avulsions have a much worse prognosis with persistent pain and instability being common 3.