Perilunate dislocations

carpal dislaocation

1. DR RASHIK ISMAIL
20/11/17
CARPUS DISLOCATIONS

2. INCLUDES
1) PERILUNATE DISLOCATIONS & # - DISLOCATIONS
2) SCAPHOLUNATE DISSOCIATION
3) LUNOTRIQUETRAL DISSOCIATION
4) ULNOCARPAL DISSOCIATION

3. ANATOMY
The wrist is composed of two rows of bones that provide motion and transfer forces.
C, capitate; H, hamate; L, lunate;
S, scaphoid; T, triquetrum; P, pisiform; Td, trapezoid; Tm, trapezium.

5. Gilula arcs outline proximal and distal surfaces of the proximal carpal row and
the proximal cortical margins of capitate and hamate.

6. Normal anatomic
relationships
1)Radial inclination (23 degrees)
2)Radial length (11mm)
3)Volar tilt (12 degreee)
4) Zero degree Capitolunate angle
5)Carpal height ratio (0.53)
6)Scapholunate angle (47 degrees)
Lunate is the key to carpal stability.
Carpal height ratio
SL ANGLE

7. Wrist Ligaments
Extrinsic
Connect radius to carpus & carpus to metacarpals
Intrinsic
Connect carpal to carpal bone.
oSpace of Poirier: ligament free area btw
radioscapholunate lig & long radiolunate ligament- at
level of midcarpal joint;an area of potential weakness.

8. Extrinsic ligaments
EXTRINSIC : Palmar aspect EXTRINSIC : Dorsal

9. Pathomechanics
Classically, the radius, lunate, and capitate have
been described as a central “link” that is colinear in
the sagittal plane.
 Scaphoid serves as a connecting strut. Any flexion
moment transmitted across the scaphoid is balanced
by an extension moment at the triquetrum.

10. DISI
 When the scaphoid is
destabilized by fracture or
scapholunate ligament
disruption, the lunate and
triquetrum assume a position
of excessive dorsiflexion
(dorsal intercalated segmental
instability [DISI] ) and the
scapholunate angle becomes
abnormally high (>70
degrees).

11. VISI
When the triquetrum is
destabilized (usually by
disruption of the
lunotriquetral ligament
complex), the opposite
pattern (volar intercalated
segmental instability [VISI] )
is seen as the lunate
(intercalated segment) volar
flexes.

12. MECHANISM OF INJURY
FOOSH; axial compressive force
wrist hyperextension,
ulnar deviation, and
intercarpal supination

13. PERILUNATE DISLOCATION &
FRACTURE -DISLOCATIONS

14. Introduction
High energy injury with poor functional outcomes.
Commonly missed (~25%) on initial presentation.

15. Two categories
Perilunate dislocation 
lunate stays in position while carpus dislocates
4 types
transcaphoid-perilunate (MC)
perilunate
transradial-styloid
transcaphoid-trans-capitate-perilunar
 Lunate dislocation   
lunate forced volar or dorsal while carpus remains aligned

16. Mechanism
traumatic, high energy
occurs when wrist extended and ulnarly deviated
leads to intercarpal supination

17. Pathoanatomy
Sequence of events (Mayfield)
 scapholunate ligament disrupted -->
disruption of capitolunate articulation --> 
disruption of lunotriquetral articulation --> 
failure of dorsal radiocarpal ligament --> 
lunate rotates and dislocates, usually into carpal tunnel.

18. Dislocation can course through
Greater arc
ligamentous disruptions with associated fractures of
the radius, ulnar, or carpal bones.  
Lesser arc
purely ligamentous. 
Greater
Lesser

19.  Mayfield Classification
STAGE
1 Scapholunate dissociation
2  + Lunocapitate disruption
3  + Lunotriquetral disruption, "perilunate"
4 Lunate dislocated from lunate fossa (usually volar)
 •associated with median nerve compression

20. 1.SCAPHOLUNATE
DISSOCIATION
2. LUNOCAPITATE
DISRUPTION

21. 3.  LUNOTRIQUETRAL DISRUPTION,


“PERILUNATE"
4.LUNATE DISLOCATION

22. CLINICAL FEATURES
Symptoms
acute wrist swelling and pain
Median nerve symptoms may occur in ~25% of patients
MC in Mayfield stage IV where the lunate dislocates into
the carpal tunnel

23. IMAGING
Radiographs
PA/lateral wrist radiographs
AP 
break in Gilula's arc
Lunate and capitate overlap
Lunate appears triangular "piece-of-pie“ sign 
Lateral 
loss of colinearity of radius, lunate, and capitate
SL angle >70 degrees
MRI
usually not required for diagnosis

24. MANAGEMENT
NON OPERATIVE
Closed reduction and casting
Indications
ono indications when used as definitive
management
Outcomes
ouniversally poor functional outcomes with non-
operative management
orecurrent dislocation is common

25. Closed Reduction technique of Tavernier
finger traps, elbow at 90 degrees of flexion
hand 5-10 lbs traction for 15 minutes
dorsal dislocations are reduced through wrist extension,
traction, and flexion of wrist.
apply sugar tong splint
follow with surgery.

26. OPERATIVE
1) Emergent closed reduction/splinting followed
by open reduction, ligament repair, fixation, possible
carpal tunnel release.
2) Proximal row carpectomy
3) Total wrist arthrodesis

27. 1) Emergent closed reduction/splinting
followed by open reduction,ligament
repair, fixation,
Indications
all acute injuries <8 weeks old
Outcomes
Emergent closed reduction leads to 
Decreased risk of median nerve damage
Decreased risk of cartilage damage
Return to full function unlikely
Decreased grip strength and stiffness are common

28. Approaches – Dorsal, Volar, Combined.
Dorsal approach
longitudinal incision centered at Lister's tubercle
excellent exposure of proximal carpal row and
midcarpal joints
does not allow for carpal tunnel release
Volar approach
extended carpal tunnel incision just proximal to
volar wrist crease

29. Combined dorsal/volar approach
Pros
added exposure
easier reduction
access to distal scaphoid fractures
ability to repair volar ligaments
carpal tunnel decompression
Cons
some believe volar ligament repair not necessary
increased swelling
potential carpal devascularization
difficulty regaining digital flexion and grip

30. Technique
Fix associated fractures
Repair scapholunate ligament
Protect scapholunate ligament repair
Repair of lunotriquetral interosseous ligament
Post-op
Short arm thumb spica splint converted to short arm
cast at first post-op visit
Duration of casting varies, but at least 6 weeks

31. 2) Proximal row carpectomy
 Technique
Dorsal and volar incisions if median nerve compression is present
Volar approach allows median nerve decompression with excision
of lunate
Dorsal approach facilitates excision of the scaphoid and
triquetrum

32. Complications
 Median N neuropathy.
Chronic perilunate injury.
Post traumatic arthritis.

33. SCAPHOLUNATE
DISSOCIATION

34. INTRODUCTION
Scapholunate ligament is important for carpal stability
chronic scapholunate deficiency DISI
Ligamentous analog of scaphoid #
Acute/ Degenerative injury.
3components: Dorsal, Proximal & Volar
Associated injuries
DISI
Scaphoid flexes palmar and the lunate dorsiflexes
if untreated, progress into a SLAC 

35. ANATOMY
Scapholunate interosseous ligament
Location
C-shaped structure connecting the dorsal, proximal and
volar surfaces of the scaphoid and lunate bones
dorsal fiber thickened (2-3mm) compared to volar
Biomechanics
Dorsal component provides the greatest constraint
to translation between the scaphoid and lunate bones

36. CLINICAL EXAMINATION
ASB tenderness
Pain increased with extreme wrist extension and radial deviation
Watson test +ve
When deviating from ulnar to radial, pressure over volar aspect of
scaphoid produces a clunk secondary to dorsal subluxation of the
scaphoid over the dorsal rim of the radius.

37. IMAGING
oAdditional radial and ulnar deviation views & clenched fist
Findings
PA radiographs
SL gap > 3mm  (Terry Thomas sign)  
cortical ring sign (caused by scaphoid malalignment)  
scaphoid shortening
Lateral radiographs
dorsal tilt of lunate leads to SL angle > 70° 
capitolunate angle > 20°

38. Terry Thomas sign
Cortical
ring

39. Imaging (Contd…)
Arthrography
as screening tool
always assess the contralateral wrist for comparison
demonstrate the presence of a tear.
Arthroscopy
gold standard for diagnosis

40. MANAGEMENT
Nonoperative
NSAIDS, rest +/- immobilization
Indications
acute, undisplaced SLIL injuries
chronic, asymptomatic tears

41. Operative
SURGERY INDICATION
SL Ligament repair acute scapholunate ligament injury
without carpal malalignment
SL reconstruction Acute, SL lig not ammenable to repair
Scaphoid ORIF vs. CRPP SL ligament injury is d/t scaphoid #
Stabilization with wrist fusion
(STT/SLC)
rigid and unreducible DISI deformity

42. Complications
Disease progression (e.g. SLAC wrist)
Arthritis
Post-operative pain, stiffness, fatigue
Reduced grip strength

43. THANK YOU