Thumb Spica Splint for Thumb Dislocation
For a patient with thumb dislocation, immobilize with a thumb spica cast or splint for 3-6 weeks following reduction, with follow-up radiographs at 10-14 days to ensure maintained alignment. 1
Immediate Post-Reduction Management
- Apply a thumb spica splint immediately after successful closed reduction to maintain joint stability and prevent re-dislocation 1, 2
- Obtain radiographic assessment with at least 2 views (PA and lateral) to confirm adequate reduction and rule out associated fractures 1
- Schedule follow-up radiographs at 10-14 days to verify the fracture or dislocation position remains stable 3
Splint Selection and Duration
- Use either a rigid thumb spica cast or a custom-made thermoplastic/neoprene thumb spica splint for the full immobilization period 3, 1
- Continue immobilization for 3-6 weeks minimum to allow adequate soft tissue healing 1, 2
- For stable reductions after early treatment, a scaphoid-type cast (which includes thumb immobilization) for 6 weeks is sufficient 2
Indications for Surgical Intervention
Proceed directly to surgical fixation rather than splinting alone if:
- Fracture fragment displacement exceeds 3mm 1
- More than one-third of the articular surface is involved 1
- Joint remains unstable after closed reduction attempts 2, 4
- Treatment is delayed beyond the acute injury period 2
For unstable dislocations, percutaneous Kirschner wire fixation should be performed, followed by thumb spica immobilization for 6 weeks 2, 4
Special Considerations for Osteoporosis
Given the concern for underlying osteoporosis in this patient:
- Maintain a lower threshold for surgical stabilization, as osteoporotic bone may not maintain reduction as reliably with splinting alone 5
- Initiate calcium (1000-1200 mg/day) and vitamin D (800 IU/day) supplementation immediately to support bone healing 5
- Arrange for DEXA scan evaluation once the acute injury has healed to assess fracture risk 5
- Consider early orthogeriatric consultation for patients over 50 with fragility-type injuries 5
Post-Immobilization Rehabilitation
After the 3-6 week immobilization period:
- Begin with gentle passive range of motion exercises before progressing to active-assisted movements 3
- Initiate progressive strengthening exercises focusing on thumb stability and grip strength 3
- Consider transitioning to a removable custom orthosis for symptom relief during activities if residual pain persists 5, 3
- Hand exercises to improve joint mobility and muscle strength should be incorporated for all patients 6
Common Pitfalls to Avoid
- Do not use internal fixation alone without addressing capsular and ligamentous injuries, as this leads to persistent dorsal subluxation in up to 50% of cases 4
- Avoid premature discontinuation of immobilization before 3 weeks, as this significantly increases risk of re-dislocation 2
- Do not rely on compression wraps or soft supports for acute dislocations—rigid immobilization is essential 7
- Ensure the splint is properly fitted and custom-made, as poorly fitted orthoses lead to poor compliance and treatment failure 6