Hand Fractures/Dislocations

What three structures provide the greatest stability to the proximal interphalangeal (PIP) joint?

The three-sided box configuration of the medial and lateral collateral ligaments and the volar plate.

What is the classification of Mallet fractures of the finger?

Type 1: closed tendon avulsion with or without fracture

Type 2: laceration with extensor tendon disruption

Type 3: open injury with loss of skin and tendon substance

Type 4: physeal fracture in children

What is the treatment of choice for a displaced fracture of the dorsal base of the distal phalanx comprising over 25% of the articular surface?

Operative intervention with closed or open reduction and internal fixation.

What is the treatment of choice for a volar base fracture of the distal phalanx with loss of the flexor digitorum profundus insertion?

Open reduction and internal fixation.

What is the acceptable angulation for metacarpal shaft fractures (index, middle, ring, and little)?

1. Index metacarpal: 10 to 15 degrees

2. Middle metacarpal: 10 to 15 degrees

3. Ring metacarpal: 30 to 35 degrees

4. Small metacarpal: 40 to 45 degrees

What is the most likely direction of angulation of an unstable transverse metacarpal shaft fracture?

Apex dorsal angulation due to the volar directed pull of the interosseous muscles.

What are some indications for operative fixation of phalangeal and metacarpal fractures?

• Malrotation

• Irreducible fractures

• Intra-articular fractures

• Open fractures

• Fractures with bone loss

• Fractures with associated tendon, vascular or nerve injury

• Polytrauma patients

How does one assess for malrotation in phalangeal and metacarpal fractures?

The hand is assessed with the fingers in extension and flexion. In extension the fingers should be parallel and in flexion they should all point toward the scaphoid tuberosity. Malrotation would present as subtle overlap or scissoring of the fingers.

What is the number one complication of operatively treated phalangeal fractures?

Digital stiffness.

What is the most likely block to reduction in a complex dorsal dislocation of the metacarpophalangeal (MCP) joint?

Volar plate.

What two structures act as a noose around the metacarpal head in an irreducible (complex) dorsal dislocation of the index MCP joint?

The flexor tendons (ulnarly) and the lumbricals (radially) maintain a tight encirclement around the narrow neck of the metacarpal preventing reduction.

In a Bennett fracture, what is the deforming force that causes proximal migration of the thumb metacarpal?

Abductor pollicis longus.

What is a Stener lesion?

A Stener lesion is formed when the distally avulsed ulnar collateral ligament of the thumb MCP joint comes to lie dorsal to the leading edge of the adductor aponeurosis.

What are the most reasonable treatment options for a fracture/dislocation of the PIP joint with a severely comminuted volar base fracture of the middle phalanx involving 40% of the joint surface?

Volar plate arthroplasty or Suzuki-type dynamic external fixation/traction.

In volar dislocation of the PIP joint, what commonly associated injury must be examined for?

Rupture or avulsion of the extensor tendon central slip.

What is the treatment for a fifth metacarpal neck fracture (Boxer fracture) with 40 degrees of apex dorsal angulation?

40 degrees is the maximal angulation acceptable; however, some would suggest attempted closed reduction to improve angulation and ulnar gutter splinting.

What is the most common carpal bone fractured?