Hand Fractures And Dislocation

hand fractures and dislocations

Hand Anatomy

• Metacarpals

Phalanges: distal, medial, proximal

Joints: distal interphalangeal (DIP), proximal interphalangeal (PIP) and metacarpophalangeal (MCP)

Hand Anatomy

Imaging

• Plain radiographs: multiple views are necessary:

AP / PA

• Lateral
• Oblique

CT Scan

First Metacarpal Fractures

Bennett and Rolando fractures are intra-articular MCP fracture-dislocations of the thumb.

These fractures must be distinguished from extraarticular fractures located distal to the carpometacarpal (CMC) joint because the former may require open reduction.

Bennett fracture

A Bennett fracture is a fracture of the base of the thumb resulting from forced abduction of the first metacarpal.

It is defined as an intra-articular two-part fracture of the base of the first metacarpal bone.

Plain radiographic features

• Two-piece fracture of the base of the thumb metacarpal
• Fracture line (radiolucent line)
• Intra-articular extension

Dorsolateral displacement

A small fragment of the 1st metacarpal, attached to the anterior oblique ligament, continues to articulate with the trapezium.

Lateral retraction of the first metacarpal shaft by the abductor pollicis longus When an intra-articular fracture of the 1st metacarpal is comminuted, producing at least three parts, it is referred to as a Rolando fracture which has a worse prognosis

• Dorsal and radial dislocation (force from abductor pollicis longus)

• Small fragment maintains articulation with trapezium.

Rolando fracture

Is a three-part or comminuted intra-articular fracture-dislocation of the base of the thumb (proximal first metacarpal).

It can be thought of as a comminuted Bennett fracture.

Rolando Fracture

• Comminuted Bennett fracture; the fracture line may have a Y, V, or T configuration.

BOXER'S FRACTURE

Fracture of the MCP neck (most commonly fifth MCP) with volar angulation and often external rotation of the distal fragment Fracture of the 3rd, 4th, and 5th MCP, with angulation and external rotation of distal fragment

4th and 5th metacarpal fracture

Fracture of phalanges

• Mechanism of Injury:
• Stepped on (direct force)
• Hit on the tip of finger

Twisting/torsion

Hand Fractures And Dislocation

Mallet Finger. A small avulsion injury is noted at the base of the distal phalanx, which is where the extensor digitorum tendon inserts. This is termed a mallet finger or baseball finger because it is often caused by a baseball striking the distal phalanx and causing the avulsion

MALLET FINGER

Proximal Phalanx

• More common than middle phalanx fractures.
• May result in a great deal of disability.

Dorsal or palmar angulation may occur with these fractures.

Primer of Diagnostic Imaging fifth edition – Weissleder,

• Radiopedia professional website

Imaging of Othopaedic- Springer 2007