Management of Acute Salter-Harris Type 2 Fracture of the Thumb
For an acute Salter-Harris type 2 fracture of the thumb in a pediatric patient, perform closed reduction under local anesthesia in the emergency department if displaced, followed by immobilization with a thumb spica splint or cast for 4-6 weeks. 1, 2, 3
Initial Assessment and Imaging
- Obtain a standard 2-view radiographic examination of the thumb (PA and lateral), which shows most thumb fractures adequately, though an oblique projection slightly increases diagnostic yield 4
- Examine specifically for rotational deformity by assessing finger cascade alignment when the hand is in a fist position—even 5 degrees of angulation can cause clinically evident rotational deformity 3
- Check for any nailbed laceration, as this converts the fracture to an open Seymour fracture requiring urgent surgical management 5
Treatment Algorithm
Non-Displaced or Minimally Displaced Fractures (<3mm)
- Immobilize in a thumb spica cast or posterior splint for 4-6 weeks 1, 2, 6
- A posterior splint provides superior pain relief during the first two weeks compared to other immobilization methods 1
Displaced Fractures (≥3mm displacement or any rotational deformity)
- Perform closed reduction under local anesthesia in the emergency department 2, 3
- Satisfactory closed reduction can be obtained with local anesthesia without requiring general anesthesia or operating room resources 3
- After reduction, immobilize in thumb spica cast for 4-6 weeks 1, 2
- If closed reduction fails to achieve <3mm displacement, open reduction with internal fixation is indicated using techniques that avoid violating the growth cartilage 2
Critical Timing Considerations
If there is an associated nailbed laceration (open Seymour fracture), treatment must occur within 24 hours to prevent infectious complications:
- Acute appropriate treatment (irrigation, debridement, reduction, antibiotics within 24 hours) has 0% infection rate 5
- Delayed treatment beyond 24 hours carries a 45% infection rate, including osteomyelitis 5
- This seemingly innocuous injury requires urgent surgical management when the nailbed is involved 5
Follow-Up Protocol
- Obtain radiographic verification between days 7-14 after reduction to detect early malunion 2
- Schedule follow-up at 3-4 weeks to assess healing progress and ensure no displacement has occurred 7
- Avoid routine follow-up imaging beyond this if there are no clinical concerns, as pediatric patients have excellent remodeling potential 1, 8
- Total immobilization duration is typically 4-6 weeks, after which joint mobility exercises should begin 1, 2
Common Pitfalls to Avoid
- Missing rotational deformity on initial examination—always assess finger cascade alignment clinically, as radiographs may not clearly demonstrate rotation 3
- Failing to recognize an associated nailbed laceration, which converts this to an open fracture requiring urgent surgical treatment within 24 hours 5
- Accepting displacement >3mm without reduction, as malunited fractures require surgical intervention with more complex techniques 2, 6
- Overtightening the cast or splint, which can compromise circulation, particularly important in young children 7
Expected Outcomes
- Properly reduced and immobilized fractures heal within 30-45 days with normal joint mobility 2
- The overall complication rate for appropriately treated Salter-Harris II fractures is approximately 2%, with displaced fractures carrying a 17% complication rate if reduction is required 6
- Growth arrest is rare but possible with displaced fractures, emphasizing the importance of anatomic reduction 6