Thumb Metacarpal Fractures

Alan M. Hirahara, M.D.

Fracture Classification

Intra-articular

I - Bennett Fx

II - Rolando Fx

Extra-articular

IIIA - Transverse

IIIB - Oblique

IV - Children’s physeal

Bennett’s Fracture

• Fracture-dislocation

• First described by Bennett in 1882

• Mechanism of injury– Axial blow directed against the partially flexed

metacarpal– Commonly sustained in fistfights

Bennett’s Fracture

• Fracture line separates major part of MC from small volar lip fragment, producing disruption of CMC joint

Bennett’s Fracture

• Avulsion rather than pure dislocation secondary to strength of anterior oblique ligament (AOL), which anchors volar lip of MC to tubercle of trapezium

Bennett’s Fracture

• Primary variables– Size of volar lip

fragment

– Amount of displacement of shaft

• Associated injuries– Trapezium fractures

– Rupture of MP joint collateral ligaments

Deformity

• Primary forces– Base of MC pulled

dorsally & radially by AbdPL

– Distal attachment of adductor levers base further dorsally

Treatment

• Closed Reduction

• Percutaneous Pin Fixation– Trans-meta

– Trapezium-MC

– Intramedullary

• Open Reduction, Internal Fixation– Herbert screw

– AO screw

• External Fixator

Treatment

• Accept 2 mm displacement– Criteria not well established– OKU Hand & Campbell’s - Accepts 1-3 mm

• 4 weeks thumb spica cast

Bennett Fx - Options

Bennett Fx - CRPP 1

Bennett Fx - CRPP 2

Bennett Fx - CRPP 3

Bennett Fx - CRPP 4

Bennett Fx - ORIF

Rolando’s Fracture

• Rolando described fracture in 1910– Volar lip fragment & large dorsal fragment,

resulting in Y- or T-shaped intra-articular fracture

– Commonly severe comminution

• Least common of adult thumb MC fx

• Prognosis - Poor

Rolando Fx - Xray 1

Rolando Fx - Xray 2

Treatment

• ORIF only attempted if volar & dorsal components are single large fragments

• Traction

• External Fixation

• Limited immobilization with early attempt at remolding via mobilization

Rolando Fx - ORExFix 1

Rolando Fx - ORExFix 2

Rolando Fx - Ex Fix

Rolando Fx - ORIF

Extra-articular Fractures

• Most frequent fracture in thumb metacarpal

• Surgery rarely indicated

• Closed manipulation under regional or local anesthesia

• Spica cast x 4 weeks

Extra-articular Fx - Xray

Extra-articular Fractures

• Avoid hyperextension of MP joint

• Failure to achieve exact alignment not an indication for open reduction

• Can accept 20-30° of residual angulation, without detectable limitation of motion

• Oblique type – With marked vertical inclination, percutaneous

pinning may be necessary

Extra-articular Fx - CRPP