Treatment of Left Thumb Dislocation
For an acute left thumb dislocation, perform immediate closed reduction followed by immobilization in a thumb spica cast or splint for 3-6 weeks, with surgical intervention reserved for cases with fracture fragment displacement >3mm or involvement of more than one-third of the articular surface. 1
Initial Diagnostic Imaging
- Obtain at least 2-view radiographs (posteroanterior and lateral) immediately to assess for associated fractures, fracture fragment displacement, and articular surface involvement 1
- Most thumb fractures are visible on 2-view examination, though adding an oblique projection slightly increases diagnostic yield 2
- The location of the dislocation matters critically—distinguish between interphalangeal (IP) joint, metacarpophalangeal (MCP) joint, or carpometacarpal (CMC) joint dislocations, as each has different treatment implications 3
Treatment Algorithm Based on Dislocation Type
For Simple Dislocations Without Significant Fracture
Closed reduction with immediate immobilization is the treatment of choice: 1, 4
- Perform closed reduction in the emergency department
- Apply thumb spica cast or splint for 3-6 weeks 1
- Arrange close follow-up with hand surgery 5
Indications for Surgical Intervention
Proceed directly to surgical fixation if: 1
- Fracture fragment displacement exceeds 3mm
- More than one-third of the articular surface is involved
- The dislocation is irreducible by closed means (volar plate or flexor tendon may be blocking reduction) 6
Special Consideration for CMC Joint Dislocations
CMC joint dislocations require more aggressive management due to high rates of recurrent instability and post-traumatic arthritis: 7
- Early ligamentous reconstruction (within 7 days) is superior to closed reduction and pinning alone for CMC dislocations 7
- Closed reduction with pinning alone resulted in 50% requiring revision surgery for recurrent instability or degenerative arthritis 7
- Early reconstruction with flexor carpi radialis weave preserved range of motion and grip strength with minimal degenerative changes 7
- For chronic CMC dislocations, open reduction with pin fixation and dorsoradial ligament repair with augmentation is effective 8
Post-Reduction Management
- Maintain immobilization for 3-6 weeks in thumb spica cast or splint 1
- Monitor for pain relief and restoration of function during follow-up 1
- After cast removal, initiate rehabilitation program focusing on joint mobility and muscle strength 4
Critical Pitfalls to Avoid
Do not miss irreducible dislocations: The volar plate or flexor pollicis longus tendon can become interposed and block closed reduction, particularly in IP joint dislocations—if reduction is not easily achieved, suspect soft tissue interposition and proceed to open reduction 6
Do not undertreated CMC dislocations: Simple closed reduction and pinning of CMC joint dislocations leads to unacceptably high failure rates; early ligamentous reconstruction should be strongly considered 7
Do not delay diagnosis in osteoporotic patients: Patients with underlying osteoporosis have increased risk of associated fractures that may be radiographically occult initially—maintain high index of suspicion and consider repeat imaging at 10-14 days if clinical suspicion persists despite negative initial films 2
Long-Term Considerations for Osteoporotic Patients
If the patient develops post-traumatic thumb base osteoarthritis:
- Consider long-term orthosis use for symptom relief 2, 3, 1
- Initiate exercises to improve function and muscle strength 2, 3
- Topical NSAIDs are first-line pharmacological treatment due to favorable safety profile in older patients with comorbidities 2, 3
- Reserve surgery (trapeziectomy, interposition arthroplasty) for severe cases when conservative treatments fail 3, 1