Treatment of Thumb Metacarpal Fracture
For thumb metacarpal fractures, initial management depends on fracture pattern: extra-articular fractures with <30° angulation can be treated with closed reduction and thumb spica immobilization, while intra-articular fractures (Bennett and Rolando) require anatomic reduction with <1 mm articular step-off, typically achieved through closed reduction with percutaneous K-wire fixation for Bennett fractures or open reduction with internal fixation for complex patterns. 1
Initial Diagnostic Approach
Imaging requirements:
- Obtain at minimum a 2-view radiographic examination (PA and lateral), though adding an oblique projection slightly increases diagnostic yield for thumb fractures 2
- A standard 3-view examination of the hand (PA, lateral, and oblique) is preferred when evaluating the entire hand 3
- CT is generally not indicated for acute metacarpal fractures unless there is concern for complex articular involvement 2, 3
Treatment Algorithm by Fracture Type
Extra-Articular Fractures
Conservative management is appropriate when:
- Angulation ≤30° (compensatory motion at the thumb CMC joint tolerates this deformity) 4, 1
- No malrotation present 4
- Shortening <5 mm 4
Treatment approach:
- Closed reduction followed by thumb spica cast immobilization for 4 weeks 5, 6
- The substantial compensatory motion at the trapeziometacarpal joint allows tolerance of up to 30° angulation without significant functional impairment 1
Intra-Articular Fractures (Bennett and Rolando)
Bennett fractures (two-part intra-articular):
- Primary treatment: Closed reduction with percutaneous K-wire fixation through the metacarpal shaft to the trapezium 5, 1
- Use 1-2 K-wires for stabilization 5
- Immobilize for 4 weeks post-operatively 5
- Good functional results occur even with some residual deformity, though the goal remains anatomic reduction with <1 mm articular step-off to minimize posttraumatic arthritis risk 1
Large Bennett fragments:
- Open reduction and internal fixation is preferred to achieve anatomic reduction with rigid fixation and allow early range of motion 1
Rolando fractures (three-part or comminuted intra-articular):
- Simple three-part patterns: Open reduction with internal fixation 1
- Comminuted patterns: External fixator application with limited open reduction and internal fixation, followed by bone grafting of metaphyseal defects if necessary 5, 1
Delayed Presentation
- When closed reduction is unsuccessful in delayed cases, proceed to open reduction with K-wire pinning 5
Post-Operative Management
Critical rehabilitation principles:
- Initiate active finger motion exercises immediately following stable fixation to prevent stiffness (the most common functionally disabling complication) 3
- Wrist motion does not need early initiation following stable fracture fixation 3
- When external fixation is used, limit the duration to reduce complications 3
- Consider vitamin C supplementation for prevention of disproportionate pain 3
Common Pitfalls and Caveats
Imaging errors:
- Relying on only 2 views may miss fracture details; obtain at least 2 views for thumb, preferably 3 views when imaging the entire hand 2, 7
- Delayed diagnosis from inadequate initial imaging can lead to functional impairment 7
Treatment considerations:
- Severe deforming forces act to displace thumb base fractures into varus and shortened positions, making maintenance of reduction challenging 1
- Secondary degenerative changes (trapeziometacarpal joint narrowing) are commonly observed even after successful operative treatment (seen in 76% of cases in one series) 5
- Despite radiographic changes, functional outcomes remain good with proper treatment—patients typically return to previous occupations including manual labor 5
Surgical indications that should not be missed: