PHALANX FRACTURES

Question 1

Most common location for phalanx fractures

Answer 1

Distal phalanx

Question 2

Mechanism of injury for phalanx fractures

Answer 2

Depends on age

• young = sports injuries
• middle aged = occupational injuries (machinery)
• old = falls

Question 3

Clinical assessment of rotational deformity with phalanx fractures

Answer 3

Look for scissoring of digit with tenodesis effect

Question 4

Deformity with proximal phalanx fractures

Answer 4

Proximal fragment pulled into flexion by interossei
Distal fragment pulled into extension by central slip
Results in apex volar angulation

Question 5

Deformity with middle phalanx fractures

Answer 5

1. Fracture distal to FDS insertion (neck or distal shaft):
   - proximal fragment pulled into flexion by FDS insertion
   - distal fragment pulled into extension by terminal extensor tendon
   - results in apex volar angulation
2. Fracture proximal to FDS insertion (base or proximal shaft):
   - proximal fragment pulled into extension by central slip
   - distal fragment pulled into flexion by FDS insertion
   - results in apex dorsal angulation

Question 6

Indications for surgical management of phalanx fractures

Answer 6

1. Open fractures
2. Displaced intra-articular fractures
   - > 1/3 articular surface = joint subluxation
   - pilon fractures = comminuted base fractures
3. Fractures with significant angulation or shortening
   - angulation > 10deg
   - shortening > 2mm
4. Any rotational deformity = scissoring

Question 7

Classification of middle phalanx base fractures

Answer 7

Partial articular vs. complete articular
Partial articular:
1. Volar base 
- hyperextension injury
- avulsion of volar plate 
2. Dorsal base 
- hyperflexion injury
- avulsion of central slip
3. Lateral base
- avulsion of collateral ligaments
Complete articular = pilon fractures

Question 8

Tuft fracture definition

Answer 8

Distal phalanx fracture caused by crush injury
Generally stable = nail plate dorsally and pulp volarly
Often associated with nail bed or pulp laceration

Question 9

Classification of distal phalanx base fractures

Answer 9

1. Volar base
   - hyperextension injury
   - avulsion of FDP insertion
2. Dorsal base
   - hyperflexion injury
   - avulsion of terminal extensor tendon