Phalanx Fractures - Hand

Introduction

Common hand injuries that can be broken into the following injuries
- proximal phalanx
- middle phalanx
- distal phalanx
Epidemiology
- incidence
  - most common injuries to the skeletal system
  - accounts for 10% of all fractures
- demographics
  - more common in males 2:1
- location
  - distal phalanx > middle phalanx > proximal phalanx
  - small finger is most commonly affected (accounts for 38% of all hand fractures)
Pathophysiology
- mechanism of injury
  - depends on age
    - 10-29 years old - sports is most common
    - 40-69 years old - machinery is most common
    - >70 years old - falls are most common
Associated conditions
- nail bed injuries
  - associated with distal phalanx fractures

Presentation

Physical exam
- inspection
  - tenderness
  - swelling
  - deformity
  - crepitus
  - look for open wounds
- motion
  - assess for scissoring of digits
    - indicates rotational component
    - can assess via tenodesis
- neurovascular
  - assess for numbness indicating digital nerve injury
  - assess for digital artery injury via doppler

Imaging

Radiographs
- recommended views
  - PA
  - lateral
  - oblique
- findings
  - proximal phalanx
    - apex volar angulation due to
      - proximal fragment pulled into flexion by interossei
      - distal fragment pulled into extension by central slip
  - middle phalanx
    - apex volar angulation if distal to FDS insertion
    - apex dorsal angulation if proximal to FDS insertion

Proximal Phalanx Fractures

Classification
- head fractures
  - can be further classified into
    - type I - stable with no displacement
    - type II - unstable unicondylar
    - type III - unstable bicondylar or comminuted
- neck/shaft fractures
  - can be
    - transverse
    - short oblique
    - long oblique
    - spiral
  - deformity is usually apex volar angulation
    - proximal fragment in flexion (due to interossei)
    - distal fragment in extension (due to central slip)
- base fractures
  - can be
    - extra-articular
    - intra-articular
      - lateral base
Nonoperative
- buddy taping vs. splinting
  - indications
    - extraarticular fractures with < 10° angulation or < 2mm shortening and no rotational deformity
    - non-displaced intraarticular fractures
  - technique
    - 3 weeks of immobilization followed by aggressive motion
Operative
- CRPP vs. ORIF
  - indications
    - extraarticular fractures with > 10° angulation or > 2mm shortening or rotational deformity
    - displaced intraarticular fractures
    - unstable or irreducible fracture pattern
  - techniques
    - crossed K wires
    - Eaton-Belsky pinning through metacarpal head
    - minifragment fixation with plate and/or lag screws
      - lag screws alone indicated in presence of long oblique fracture

Middle Phalanx Fractures

Classification
- head fractures
  - can be further classified into
    - type I - stable with no displacement
    - type II - unstable unicondylar
    - type III - unstable bicondylar or comminuted
- neck fractures
  - deformity is usually apex volar angulation
    - proximal fragment in flexion (due to FDS)
    - distal fragment in extension (due to terminal tendon)
- shaft fractures
  - can be
    - transverse
    - short oblique
    - long oblique
    - spiral
  - deformity can be
    - apex volar angulation
      - if distal to FDS insertion
    - apex dorsal angulation
      - if proximal to FDS insertion
    - without angulation
      - due to inherent stability provided by an intact and prolonged FDS insertion
- base fractures
  - deformity is usually apex dorsal angulation
    - proximal fragment in extension (due to central slip)
    - distal fragment in flexion (due to FDS)
  - can be further classified into
    - partial articular fractures
      - volar base
        
        results from hyperextension injury or axial loading
        
        represents avulsion of volar plate
        
        unstable if > 40% articular surface involved
      - dorsal base
        
        results from hyperflexion injury
        
        represents avulsion of central tendon
      - lateral base
        
        represents avulsion of collateral ligaments
    - complete articular fractures
      - know as pilon fractures
      - unstable in all directions
Nonoperative
- buddy taping vs. splinting
  - indications
    - extraarticular fractures with < 10° angulation or < 2mm shortening and no rotational deformity
    - non-displaced intraarticular fractures
  - technique
    - 3 weeks of immobilization followed by aggressive motion
Operative
- CRPP vs. ORIF
  - indications
    - extraarticular fractures with > 10° angulation or > 2mm shortening or rotational deformity
    - displaced intraarticular fractures
    - irreducible or unstable fracture pattern
  - techniques
    - crossed K wires
    - extension block pinning
    - collateral recess pinning
    - minifragment fixation with plate and/or lag screws
    - volar plate arthroplasty

Distal Phalanx Fractures

Most common phalanx fracture
Classification
- tuft fractures
  - mechanism is usually crush injury
  - usually stable due to nail plate dorsally and pulp volarly
  - often associated with laceration of nail matrix or pulp
- shaft fractures
  - can be
    - transverse
    - longitudinal
- base fractures
  - usually unstable
  - mechanism can be
    - shearing due to axial load, leading to fracture involving > 20% of articular surface
    - avulsion due tensile force of terminal tendon or FDP, leading to small avulsion fracture
  - can be further classified into
    - volar base
    - dorsal base
- Seymour fractures
  - epiphyseal injury of distal phalanx
  - resuls from hyperflexion
  - presents as mallet deformity (i.e. apex dorsal) due to
    - terminal tendon attaches to proximal epiphyseal fragment
    - FDP attaches to distal fragment
Nonoperative
- closed reduction +/- splinting
  - indications
    - most cases
  - nail matrix may be incarcerated in fracture and block reduction
Operative
- remove nail, repair nailbed, and replace nail to maintain epi fold
  - indications
    - distal phalanx fractures with nailbed injury
    - - see nail bed injuries
- CRPP vs. ORIF
  - indications
    - displaced or irreducible shaft fractures
    - dorsal base fractures with > 25% articular involvement
    - displaced volar base fractures with large fragment and involvement of FDP
    - non-unions
  - techniques
    - longitudinal or crossed K wires
    - extension block pinning
    - minifragment fixation with lag screws

Complications

Loss of motion
- most common complication
- predisposing factors include prolonged immobilization, associated joint injury, and extensive surgical dissection
- treat with rehab and surgical release as a last resort
Malunion
- malrotation, angulation, shortening
- surgery indicated when associated with functional impairment
  - corrective osteotomy at malunion site (preferred)
  - metacarpal osteotomy (limited degree of correction)
Nonunion
- uncommon
- most are atrophic and associated with bone loss or neurovascular compromise
- surgical options
  - resection, bone grafting, plating
  - ray amputation or fusion

most common injuries to the skeletal system
account for 10% of all fractures
distal phalanx is most common fractured bone in the hand