Management of Thumb Base Fracture in Adults
For an adult with a thumb base fracture, immediate treatment depends on whether the fracture is extra-articular or intra-articular: extra-articular fractures with <30° angulation can be managed with closed reduction and thumb spica casting, while intra-articular fractures (Bennett or Rolando) require closed reduction with percutaneous K-wire fixation to achieve <1mm articular step-off and prevent post-traumatic arthritis. 1, 2
Initial Assessment and Classification
The first critical step is determining fracture pattern through radiographic evaluation:
- Extra-articular fractures involve the metaphyseal region without joint surface involvement 1
- Bennett fractures are two-part intra-articular fractures with a small ulnar fragment that remains attached to the anterior oblique ligament 1, 2
- Rolando fractures are comminuted intra-articular fractures, typically T- or Y-shaped 1, 2
The key deforming forces act to displace these fractures into varus and shortening due to the pull of the abductor pollicis longus, making reduction easy but maintenance difficult 2.
Treatment Algorithm by Fracture Type
Extra-Articular Fractures
- Closed reduction and thumb spica immobilization is appropriate for most extra-articular fractures 1, 2
- Angulation up to 30° can be tolerated because substantial compensatory motion exists at the thumb carpometacarpal joint 2
- For unstable fractures that cannot maintain reduction, consider percutaneous K-wire fixation or anterograde intramedullary headless compression screw, which allows early range of motion without crossing the articular surface 3
- Immobilization duration is typically 4-6 weeks 4
Bennett Fractures (Two-Part Intra-Articular)
- Closed reduction with percutaneous K-wire fixation is the treatment of choice for most Bennett fractures 1, 2
- The goal is anatomic reduction with <1mm articular step-off to minimize long-term risk of post-traumatic arthritis 2
- Good functional results are observed even with residual deformity, but anatomic reduction should still be pursued 1, 2
- For large Bennett fragments, open reduction and internal fixation may be necessary to achieve anatomic reduction with rigid fixation 2
Rolando Fractures (Comminuted Intra-Articular)
- Treatment depends on fragment size and comminution severity 1
- Non-comminuted or minimally comminuted fractures: open reduction and internal fixation to allow anatomic reduction with rigid fixation and early range of motion 2
- Severely comminuted fractures: external fixation with limited open reduction and internal fixation, followed by bone grafting of metaphyseal defects if necessary 1, 2
- Articular impaction in severely comminuted fractures makes restoration of the articular surface difficult and is implicated in post-traumatic arthritis 1
Critical Early Mobilization Protocol
A common pitfall is prolonged immobilization leading to debilitating stiffness:
- Begin active motion exercises of all uninjured fingers immediately to prevent stiffness 5
- Splints or casts should not obstruct movement of uninjured digits 5
- After stable fixation of intra-articular fractures, early range-of-motion exercises should begin within the first postoperative days 6
- Failure to maintain motion can result in stiffness requiring multiple therapy visits and possibly additional surgical intervention 5
Special Considerations for Patients Over 50 Years
In patients over 50, a thumb base fracture may represent an underlying fragility fracture requiring comprehensive evaluation:
- Systematically evaluate all patients for subsequent fracture risk, including review of clinical risk factors, DXA of spine and hip, imaging for vertebral fractures, falls risk assessment, and identification of secondary osteoporosis 7, 8
- Ensure adequate calcium and vitamin D intake, smoking cessation, and alcohol limitation 7, 5
- Consider initiating anti-osteoporotic therapy with drugs demonstrated to reduce vertebral, non-vertebral, and hip fractures (bisphosphonates or denosumab) 8
- For frail elderly patients with multiple comorbidities, implement orthogeriatric co-management and fall prevention programs including balance training 5
Pain Management
- Provide multimodal analgesia immediately, including acetaminophen 5
- Avoid opioids as first-line agents in elderly patients due to increased risk of falls, delirium, and mortality 8