Management of Dislocated Thumb
Dislocated thumbs should be reduced emergently in the emergency department whenever possible, followed by immobilization in a thumb spica splint or cast for 3-6 weeks, with surgical intervention reserved for cases where closed reduction fails, instability persists, or there is significant ligamentous injury. 1, 2
Immediate Management
Emergency Reduction
- Attempt closed reduction immediately in the emergency department to minimize soft tissue interposition and avoid the need for open surgery 1, 3
- Perform reduction using axial traction followed by forced flexion at the metacarpophalangeal (MCP) joint with continuous pressure over the dorsal aspect 4
- For carpometacarpal (CMC) joint dislocations, apply direct pressure over the dorsal aspect with full thumb abduction 4
- Manage as day surgery if admission is required, but prioritize emergency department reduction 1
Post-Reduction Assessment
- Obtain radiographs in at least 2 views (PA and lateral) after reduction to confirm anatomic alignment 5
- Assess for fracture fragment displacement (>3mm indicates surgical need) and articular involvement (>1/3 of surface requires surgery) 5
- Examine finger alignment during active flexion to detect any rotational malalignment, with all fingers pointing toward the scaphoid tubercle without scissoring or overlap 6
Immobilization Protocol
Conservative Management Criteria
- Immobilize in rigid thumb spica cast or splint for 3-6 weeks for successfully reduced dislocations without instability 5, 4, 2
- Obtain follow-up radiographs at 10-14 days to ensure maintained reduction 5, 6
- Institute immediate active motion exercises for uninvolved joints to prevent stiffness, which is the most functionally disabling complication 6
Surgical Indications
When Closed Reduction Fails
- Proceed to open reduction if closed reduction cannot be achieved or maintained, particularly common in delayed presentations beyond one week 3, 2
- Volar plate interposition is the most common cause of irreducible dislocations and requires surgical removal 3
- Use either dorsal or volar surgical approach; dorsal approach allows direct visualization of interposed structures 3
Specific Surgical Criteria
- Acute instability after reduction warrants percutaneous pinning followed by thumb spica immobilization 2
- Significant swelling preventing adequate assessment of stability requires fixation 2
- Loss of reduction after initial pinning, or failure to achieve anatomic reduction, requires open reduction with possible ligamentous reconstruction 2
- For chronic dislocations (>3 weeks), consider dorsoradial ligament repair with augmentation and pin fixation 7
Critical Pitfalls to Avoid
Delayed Diagnosis
- Thumb dislocations are easily missed clinically and radiologically, especially in children where swelling may obscure deformity 3
- Any persistent pain, swelling, or limited motion after "thumb sprain" warrants repeat radiographic evaluation 3
- Delayed presentation (>1 week) significantly increases the likelihood of requiring open reduction due to soft tissue contracture and interposition 3, 2
Inadequate Follow-Up
- Repeat radiographs at 10-14 days are mandatory to detect loss of reduction before soft tissue healing makes revision more difficult 5, 6
- Monitor for malrotation by having the patient actively flex all fingers—any scissoring or deviation from parallel alignment requires immediate intervention 6
- Assess for persistent pain during the first few weeks, which should prompt reevaluation for malrotation or loss of reduction 6
Expected Outcomes
- With appropriate early closed reduction and immobilization, patients typically return to full range of motion, normal power, and grip strength within 2 months 3, 8
- Successful open reduction when needed also achieves full functional recovery if performed promptly 3
- Chronic instability or residual stiffness can result in severe hand disability, emphasizing the importance of proper initial management 4, 7