Perilunate Fractures and Dislocations

Epidemiology

 

Young men in 20's and 30's

 

Aetiology

 

High energy injuries

- fall from heights

- MVA

 

Mayfield Classification

 

Injury progresses from radial to ulna

- usually disruption proximal row either side of lunate

 

1.  Capitate usually displaces dorsally initially

- volar lunate dislocation is end stage

 

2.  Volar capitate dislocations do occur

- dorsal lunate dislocation as end stage

 

Spontaneous reduction can also occur

 

Cadaver study 

 

Stage 1 - SL dissociation 

 

Stage 2 - CL dissociation / capitate dislocates

 

Stage 3 - LT dissociation

 

Stage 4 - Lunate dislocates

 

Presentation

 

Swollen and painful wrist

- +++ clinical suspicion

 

Volar lunate dislocations

- fingers semiflexed

 

1/3 have median nerve symptoms

 

Unusual to have compound wound

- usually palmar

 

X-ray

 

Disruption of Gilula's 3 smooth carpal arcs

 

Progressive Injury

 

1.  Capitate dorsal

- lunate remains with radius

- lunate looks triangular on AP

 

Scapholunate Dislocation Capitate Dorsal

 

Perilunate Dislocation 1Perilunate Dislocation 2

 

2.  Lunate dislocates

- usually volar

 

2 main groups of injury

 

1.  Dorsal trans-scaphoid dislocation

- 2/3 of cases

 

Transscaphoid Perilunate DislocationTransscaphoid Perilunate Dislocation Lateral

 

2.  Dorsal perilunate dislocation

- 1/3 of cases

 

Associated Injuries

 

Scaphoid fracture

Radial styloid fracture

Capitate fracture

 

Chronic presentations

 

Missed in 20%

- reasonable ROM

- little pain

 

May present with CTS

 

May present with flexor tendon ruptures

 

Management

 

A.  Acute perilunate dislocation

 

Initial Reduction

 

Traction under anaesthesia / conscious sedation

- dorsiflex wrist

- counterpressure on palmar lunate

- gradual wrist flexion with pressure on dorsal capitate

 

Perilunate Reduced 1Perilunate Reduced 2

 

Definitive

 

Poor results with non operative management

- require anatomical repair of proximal row

- wait 3-5 days for swelling to settle

 

1.  No scaphoid fracture

 

Reduce lunate

- closed reduction

- open reduction

 

Dorsal approach

- longitudinal incision

- 3/4 extensor compartment

- mobilise EPL laterally

- open dorsal between DRC and DIC ligaments

- joysticks in scaphoid and lunate

- reduce DISI deformity

- K wires SC / SL / LT (areas of ligament rupture)

- repair SL ligament back onto scaphoid with anchors / transosseous sutures

- ORIF any capitate fractures

- repair LT ligament + augment with capsule

 

+/- Volar approach

- difficulties reducing lunate

- perform CTD

- repair rent in volar capsule / Space of Poirier

 

Perilunate Dislocation ORIF APPerilunate Dislocation ORIF Lateral

 

Perilunate Dislocation APPerilunate Dislocation Lateral ORIF

 

Perilunate ORIF 1Perilunate ORIF 2

 

Recent trends

- add SL screw

- add Blatt capsulodesis

- repair rent in volar capsule

- make wrist as stiff as possible to prevent late OA

 

2.  Trans Scaphoid Perilunate

 

Perilunate Dislocation Closed ReductionTrans scaphoid Perilunate Pre ORIF

 

Trans scaphoid Perilunate ORIF

 

Dorsal approach

- ORIF scaphoid fracture

- repair LT ligament

- K wires LT and TC (SL ligament is intact)

- ORIF capitate

 

+/- Volar approach

- CTD

- repair rent in capsule

 

Post op

 

Aim is for a stable but stiff wrist

- 8 weeks in cast, then removal of K wires

- begin ROM

 

Results

 

80% strength

 

Reduced ROM

- usually 100o F/E

 

Chronic unreduced perilunate dislocations

 

< 6 months

 

Attempt open reduction

 

Salvage

 

Options

- scaphoidectomy + 4 corner fusion

- PRC

- wrist arthrodesis