Fracture

Epidemiology

 

Young men

 

Aetiology

 

FOOSH

- axial load, dorsiflexion and radial deviation

 

DISI occurs in ulna deviation

 

Herbert Classification

 

Type A    Stable acute fracture

 

A1 Tubercle

Scaphoid Tuberosity FractureScaphoid Tuberosity Fracture

 

A2 Incomplete waist fracture

Incomplete Scaphoid FractureScaphoid Fracture Incomplete

 

Type B    Unstable acute fracture

 

B1 Distal oblique fracture

Scaphoid Fracture 3D Isolated

 

B2 Complete waist fracture

Scaphoid Fracture Complete

 

B3 Proximal pole fracture

Scaphoid Proximal Pole Fracture

 

B4 Trans-scaphoid perilunate fracture

 

Type C    Delayed Union

 

Type D    Established Non-union

 

D1 Fibrous Union (stable)

D2 Pseudarthrosis (unstable / early deformity)

D3 Sclerotic Pseudoarthrosis (Late deformity)

D4 Avascular Necrosis (fragmented proximal pole)

 

Anatomy

 

Scaphoid is Greek for boat

- shaped more like a twisted peanut

 

Scaphoid 3D VolarScaphoid 3D Dorsal

 

Majority is articular

- except for dorsal ridge

- this is the site of entry of majority of blood supply

 

Vascularity

 

Gelberman & Menon J Hand Surg 1980

- latex injection

 

2 major vascular leashes

 

1.  Dorsal ridge artery

- branch of radial artery

- major blood supply

- 70- 80% scaphoid including proximal pole

- enters through the non articular dorsal ridge

 

2.  Distal tubercle

- palmar & superficial palmar branches of radial artery

- perfuse distal 20% to 30% of scaphoid

 

Fracture Location

 

Waist 65%

Proximal third 25%

Distal third 10%

 

Complications

 

1.  Non union

 

Undisplaced

- union > 95%

- rare with immediate immobilisation

 

Displaced

- non union 50%

 

2.  AVN

- increases the more distal the fracture (50% proximal pole)

- increases with displacement (AVN 50%)

 

3.  Malunion and DISI

- associated with increased intra-scaphoid angle

 

Clinical Features

 

Tender anatomical snuffbox

Swelling

Reduced ROM

 

X-ray

 

5 images will pick up 99% of fractures

- PA 

- Lateral

- PA in 45° oblique pronation

- PA 45o oblique supination

- PA in ulna deviation

 

Scaphoid PAScaphoid Fracture LateralScaphoid Fracture ObliqueScaphoid Fracture Long Axis

 

Increased intra-scaphoid angle / humpback deformity

- > 35o abnormal

- > 45o associated with poor outcome i.e. DISI

- also demonstrated to lead to loss of extension

 

2 week delay

 

Issue

- tender in ASB

- no sign of fracture on initial x-ray

- usual treatment is to place in cast and xray in 2 weeks

- can be delayed appearance of scaphoid fracture

 

Leslie and Dixon JBJS 1981 

- 222 fractures

- 98% seen at time of presentation

- 2% became evident over ensuing weeks

- these were only incomplete and located on concave side of scaphoid

 

Excluding scaphoid fracture

- CT - easy to obtain, inexpensive

- MRI - highly sensitive, but expensive and difficult to obtain

 

Instability 

 

1.  Displacement > 1mm on any film

2.  Intra-scaphoid > 35o

3.  Proximal pole fracture

4.  Comminution

5.  SL > 60o

6.  Radio-lunate angle > 15o

7.  Perilunate trans-scaphoid dislocation

 

Can be very difficult to assess displacement on plain films

- suggest use of CT

 

CT

 

1mm slices in sagittal plane of scaphoid

- plane of metacarpal

 

Position

- patient prone 

- hand over head

- fully pronated 

 

Scaphoid Fracture 3D CTScaphoid Fracture 3D CT

 

Bone Scan

 

Highly sensitive

- 5% to 15% incidence of false positives

 

MRI

 

Very sensitive for occult fracture

Identifies AVN

Identifies carpal instability

 

Management

 

Non operative Management

 

1.  Anatomical Snuff Box Tenderness / Normal Xray

 

Options

 

1.  POP 2/52, rexray out of plaster

2.  MRI / CT

 

2.  Acute undisplaced stable

 

Types

- displaced < 1mm

- incomplete fracture

- tuberosity fracture

 

Scaphoid cast

- short arm thumb spica cast

- long arm cast not necessary

- some evidence that thumb spica not necessary

 

Time in cast

- distal / tuberosity  6/52

- middle 1/3 8/52

- proximal 1/3 10/52

 

Management

- x-ray at 2/52 to ensure no displacement

- x-ray out of cast for union

- see at 6/12 for final xray check union

 

Non-union

- union rate 90 - 95%

 

Operative Management

 

Indications for Surgery

 

A.  Instability

- displaced > 1mm

- intra-scaphoid > 35o

- complex instability / perilunate instability

 

B.  Proximal pole

- high risk of AVN

- 30% rate non union if non displaced

- all theoretically unstable

- could suggest that all need ORIF

- require dorsal approach

 

C.  Athlete / Manual worker with undisplaced

- percutaneous fixation

- early mobilisation and return to work

 

D.  Delayed diagnosis

- may have increased non union rates

 

2.  ORIF

 

Indications

- displaced fractures

- proximal pole

 

Approach

 

1.  Volar approach

- workhorse for waist fractures

- preserves dorsal blood supply

 

2.  Dorsal approach 

- for proximal 1/3 fractures

 

Scaphoid Proximal Pole Fracture

 

Volar approach technique

 

Scaphoid ORIF Volar ApproachScaphoid ORIF Volar Approach 2Scaphoid ORIF Volar Approach 3

 

Position

- supine on arm table

- lead hand

- tourniquet

 

Approach

- volar along FCR

- deviate along thenar edge to STT joint

- elevate thenar muscles

- FCR ulna, deep branch radial artery radially with APL

- divide superficial branch radial artery

- open capsule in line with FCR

- transverse opening at STT

- will divide RSC ligament

 

Clean and reduce fracture

- K wires as joysticks

 

Cannulated headless compression screw 

- central third

- more bone contact, longer screws

- increased stability and therefore union rates

- can remove volar beak of trapezium

- pass cannulated screw wire, measure length

- drive wire into distal radius for stability

- pass screw, bury head

 

Bone graft as required

- very comminuted fracture / unstable

- humpback deformity

- distal radius if small

- iliac crest if large

 

Closure

- close capsule and repair RSC

 

Post op

- 8/52 in thumb spica

- assess union

 

Dorsal approach technique

 

Scaphoid ORIF Proximal Pole Lateral

 

3/4 Approach

- midline incision on RC joint

- open EPL, reflect radially

- sharply elevate EDC, reflect ulnarly

- open capsule over SL joint

 

Flex wrist

 

Insert K wire

- proximal fragment into distal fragment

- entry point is just radial to SL ligament

- drive into trapezium

- check position on multiple views

 

Insert screw

 

Results

 

Herbert ORIF all type B fractures

- B1 90% union (oblique)

- B2 88% union (waist)

- B3 85% union (proximal pole)

 

Percutaneous fixation

 

Advantages

- faster union rates than cast

- union approaching 100%

- less time in cast

- earlier return to work

 

Indications

- minimally displaced fracture in acceptable position

- manual workers / athletes

- anyone who wants to limit time in POP

 

Technique

 

Set up

- supine, tourniquet / arm table / II

 

Traction on thumb

- ulna deviation

- flex wrist over roll of drapes

- II shows long axis of scaphoid

 

Volar stab incision

- over scaphoid tuberosity

- slightly distal

- insert K wire in long axis / central third scaphoid

 

Check wire position

- AP / lateral / 45o obliques

- drill

- can put K wire into distal radius for stability / second K wire

 

Insert cannulated screw

- slightly shorter screw to obtain compression

- usually 24 mm

 

Post op

- POP 2 weeks

- then allow to range out of plaster

- no manual labour / heavy lifting

- check for union at 6/52