Treatment of Fracture of Base of Distal Phalanx of Thumb
For displaced fractures of the base of the distal phalanx of the thumb, operative fixation is required when the fracture involves more than one-third of the articular surface, demonstrates palmar displacement of the distal phalanx, or shows an interfragmentary gap >3 mm; otherwise, conservative management with splinting is appropriate.
Initial Diagnostic Approach
Start with 2-view radiography (PA and lateral) as the minimum standard, though adding an oblique projection increases diagnostic yield for thumb fractures 1. This imaging is sufficient to determine fracture characteristics and guide treatment decisions.
Treatment Algorithm Based on Fracture Characteristics
Non-Operative Management
Indicated for:
- Non-displaced or minimally displaced fractures
- Articular involvement <33% of joint surface
- No palmar displacement
- Interfragmentary gap ≤3 mm
Treatment protocol:
- Splint immobilization of the interphalangeal joint for 4-6 weeks for simple distal phalanx fractures 2
- Extension block splinting can achieve good to excellent results even with articular involvement of 22-47% of the volar base 3
Operative Management
Required when ANY of the following criteria are met 1:
- >33% articular surface involvement
- Palmar displacement of distal phalanx
- Interfragmentary gap >3 mm
Surgical options include:
- Transosseous indirect reduction: Minimally invasive technique providing stable fixation with early recovery and reduced complications 4
- Hook plate fixation (Aerni plate/S2-Prong-Plate): Achieves 84.79% good-to-excellent results, though carries risk of nail matrix injury 5
- Extra-articular DIP pinning: Two connected K-wires (one in distal phalanx shaft, one perpendicular to middle phalanx) removed after 1 month, showing good functional outcomes 6
Critical Pitfalls to Avoid
Nail matrix injury represents the most significant complication during operative treatment 5. Use meticulous surgical technique when approaching dorsally.
Delayed diagnosis can lead to functional impairment 1. If initial radiographs are equivocal but clinical suspicion remains high, consider CT without contrast rather than waiting 10-14 days for repeat radiographs.
Inadequate immobilization duration in conservative management leads to treatment failure. Strict adherence to the full splinting period is essential—even brief removal can compromise healing.
Post-Treatment Expectations
For operative cases, expect:
- Average pain scores of 0.4/10 at 20 weeks
- QuickDASH scores averaging 7.41/100
- Active flexion deficit of approximately 30° compared to contralateral side
- Overall hand strength reaching 85% of uninjured side 6
The key decision point is accurate assessment of the three operative criteria on initial radiographs—this single determination drives all subsequent management and directly impacts long-term function and quality of life.