carpal intability

1. CARPAL INSTABILITY
Dr.RUBEESH HASSAN

3. Carpal Anatomy
• 2 CARPAL RAWS:
DISTAL
• Trapezium, trapezoid, capitate, hamate bound
together by strong interosseous (intrinsic)
ligaments to form distal row, which moves
together as a single unit
PROXIMAL
– Scaphoid, lunate and triquetrum form the
proximal row. It has no muscle attachments
and is inherently unstable in compression
without its ligamentous attachments. Acts as
a link between the relatively rigid distal row
and the radioulnar articulations.

4. Intrinsic ligaments
• These have their origin and insertion within the
same carpal row
• Distal row
– To bind all the distal carpal bones together
• Proximal row
– Scapholunate ligament
– Lunotriquetral ligament

5. • Scapholunate ligaments is a C shaped
ligaments composed of dorsal,central and
volar subgroups.
• Dorsal subgroups is strongest,provide
maximum stability.

6. • Additional stabilizers are
• STT,SC -Dorsal stability
Provide resistance against the tendency of the
saphoid to palmar flex
.RSC AND RL Volar side stability.

7. • Lunotriquetral ligament
• 3 subgroup
• palmal aspect is thickest and provide
max stability to lunototriquetral stability.

8. • Proximal carpal bone has no tendinous
insertion and thus often termed as
INTERCALATED SEMENTS
• THREE Sets of tendons cross the proximal row
• Extrinsic flexer and extensers of fingers
• flexers and extensers of wrist
• abducter pollicis longus and EPB
•

9. Movements between the carpal bone is neglible
Movements of proximal carpal bone is
determined by their ligamentous attachments
and mechanical force of tendons that cross
the wrist.

10. Biomechanics of the Wrist
• SL ligament is the most important factor in the
spatial coherence of the carpus.
• The tendons that cross the proximal row exert
a compressive force that is resisted by the
connecting –rod action of scaphoid.
• Instability of scaphoid leads to an alternation
of the articulation between the proximal and
distal row.

11. Biomechanics of the Wrist
• During the radial deviation of the normal wrist
the trapezoid and trapezium exert a volarly
directed force on the distal pole of the scaphoid.
• This couses the scaphoid to flex about its waist.
• This force is then transmitted to the lunate via SL
ligaments and to triquetrum via LT LIGAMENTS.
• Thus proximal row radially deviate as one unit.

12. Biomechanics of the Wrist
Ulnar deviation of normal wrist causes the
hamate to project a dorsally directed force on
triquetrum.
As the triquetrum rotate dorsally by the hamate
,a competent LT imparts an extension moments
on the lunate and indirctly to scaphoid via SL
ligaments.

13. Scaphoid
Flexion bias
Triquetrum
Extension
bias
Lunate

14. • In a balanced proximal row the lunate remains
cantered on the distal radius without tilting
into flexion or exension.
• The tendons that cross the wrist exert a
compressive force across the carpus through
the centrally located capitate at capitolunate
articulation.

15. CLASSIFICATION

16. • Carpal instability is extremely difficult to
classify and many classification schemes exist,
each with advantages and disadvantages.

17. Direction of lunate
● Dorsal intercalated segmental instability (DISI)
● Volar intercalated segmental instability (VISI)
● Ulnar translocation
● Dorsal translocation

18. BASED Pattern of injury
● Carpal instability dissociative (CID)
❍ Dissociation within row
Scapholunate, lunotriquetral
● Carpal instability nondissociative (CIND)
❍ Instability between carpal rows
Midcarpal instability, capitolunate
instability, ulnar translocation

19. BASED Pattern of injury
● Carpal instability complex (CIC)
❍ Feature of CID and CIND
Perilunar injuries, axial carpal
dislocations
● Carpal instability adaptive (CIA)
❍ Extrinsic to wrist
Dorsal malunion of the distal radius that causes
CIND

20. Injury to SL ligaments-DISI

21. DISI
• SL injury –a gap opens between the scaphoid
and the lunate ,into which capitate eventually
collapse.
• The scaphoid ,now free of its tether to lunte
,assumes a position of flexion.
• Lunate no longer balanced by flexion moment
from scaphoid
• Lunate rotate dorsally ---DISI

22. Scaphoid
Flexion bias
Triquetrum
Extension
bias
Lunate

23. VISI
• Isolated injury to LT is insufficient to allow the
flexion moment of the scaphoid to palmar flex
the lunate .
• However if dorsal radiocarpal is also injured
tethering effect on dorsum of lunate is lost
• Scaphoid and lunate angle inti flexion ,while
capitate begins to migrate between lunate and
triquetrum.

24. • Thus injury to both LT and dorsal RC ligaments
leads to VISI

25. MECHANISM OF INJURY
• Fall on outstretched hand-SL AND LT
• Sports injury
• High energy trauma -RTA

26. • Dissociative carpal instability is often directly
caused by hyperextension of wrist
• Mayfield described a 4 part circular
progressive injury termed as PLI

27. MAYFIELD STAGES OF PERILUNAR
INSTABILITY
• Stage 1: dorsal migration of the proximal pole of
scaphoid with resulting injury to the scapholunate
ligaments
• Stage2: further extension ulnar deviation and
supination of carpus leads to progression of the force
• Stage 3: progression of these forces leads to
triquetrum to translate away from lunate with
resultant injury to the LT ligaments.
• Stage 4: disruption of dorsal RC ligaments allow the
lunate to rotate on its palmar ligmentous hinge and
dislocate with resultant articulation of the capitate
into the lunate facet of the radius.

28. SLAC
• Scapho Lunate Advance Collapse
• In the setting of chronic SL ligament injury
arthritic changes may occure and the
deformity of the capitate ,lunate ,and
scaphoid may become static
• The abnormal position leads to wear of
articular cartilage and serrounding articular
surface resulting in a condition known as
SLAC

29. SLAC -stages
• Stage 1:arthritic changes of the radial styloid
• Stage 2:arthritic changes of scaphoid facet of
distal radius
• Stage3:arthritis of the articulation of capitate
and lunate.

30. Clinical Features
• History
• Fall on outstretched hand
• Often presents late as a sprained wrist which fails to
resolve
• Weakness of wrist, catching ,clunking or episodes of
giving away
• Examination
• Detailed palpation of all the landmarks
• Grip strength often diminished

32. Special tests
• Scapholunate ballotment
• Kirk-Watson’s test
• Lunotriquetral ballotment
• Reagan’s with 2 hands

33. Watsons shift maneuver
• Useful in determining the presence or absence of
SL ligament injury
• Examiner sits across from the patient with a table
in between
• Grasp the radial side of hand with his same hand
• Thumb is placed over palmar side prominance of
scaphoid while fingers provide counter pressure
on the dorsum of the wrist proximal to the carpal
row.

34. Watsons....
• The examiners other hand provides ulnar to radial deviation
by grasping the metacarpals.
• As the wrist moves beyond neutral and to radial deviation
,the dorsally directed pressure on the palmr aspect of the
scaphoid may cause subluxation of scaphoid.
• This subluxaion may produce pain or apprehension in the
patient
• Or examiner may feel subluxation
• The pressure on the distal pole of the scaphoid released
and clunk may be realized as scaphoid relocate.
• Always examine opposite side also –lig laxity

36. Scaphoid ballotment test
• Patient hand is held in pronation.
• Examiner stabilise the lunate betwen thumb
and dorsally and index volarly
• Hold scaphoid also in similar manner
• Scaphoid is transilated dorsally and volarly
while noting the pain and transilation

38. Reagan test
• Lunatriquetral ballotment

39. INVESTIGATION
• X ray
PA
LATERAL VIEW
OBLIQUE VIEW Evaluate static
instability

40. • PA film in radial
and ulnar deviation
• Flexion and extension lateral view dynamic
• Clenched fist view

41. The lines of Gilula

44. MRI
• FOR ligaments tear
• 3 T MRI IS 86 % SENSITIVE

45. ARTHOGRAPHY

46. • GOLD STANDARD for diagnosis of SL /LT
ligaments tear is wrist arthroscopy
• Detect the tear and arthritic changes

47. Treatment
• Presence of arthritis
• Degree of instability
• Chronicity of condition
• Associated injury
• Functional demands of patients must be
considered

48. Non operative treatment
• Dynamic instability in acute setting may be
amenable to conservative treatment
• But patient must understand the
complication like future arthritis
• NSAIDLOCAL STEROID
• Activity modification
• Immobilisation

49. Treatment
SL injury
partial tear 1. Arthroscopic
debridement
+/- percutaneous
pinning
2.capsulodesis

50. Dynamic instability without diastasis
• Arthroscopic debridement +/- percutaneous
pinning
• Capsulodesis
• RASL Screw fixation
• Brunelli reconstruction

51. Acute tear with reducible diastasis
• Ligament repair –transosseous suture/anchor
suture
• Capsulodesis
• RASL Screw fixation
• Brunelli reconstruction

52. Chronic tear with reducible diastasis
• Capsulodesis
• Blatt capsulodesis
• dorsal intercarpal lig capsulodesis
• RASL Screw fixation
• Brunelli reconstruction
• Interosseous graft

53. irreducible diastasis/SLAC changes
• Scaphotrapeziotrapezoid Arthrodesis
• Proximal row carpectomy
• Scaphoid excision with 4 corner fusion

54. RASL procedure
• If repair of the scapholunate ligament is not
possible,a headless compression screw may
be used to approximate the scapholunate
ligament via open /arhroscopic approach
called a reduction and association of scaphoid
and lunate procedure(RASL)

55. CAPSULODESIS
• BLATT CAPSULODESIS- this technique tether
the scaphoid to the distal radius via a flap of
dorsal capsuloligamentous tissue secured with
suture anchor
• Loss of wrist flexion

56. capsulodesis
• Dorsal intercarpal ligament capsulodesis
• Tether the scaphoid to triquedrum
• This leads to long term acceptable function of
the wrist at the cost of early arthritis
degeneration.

57. BRUNELLI RECONSTRUCTION
• Stabilizes the scaphoid in reduced position by
passing FCR tendon through an interosseos
scaphoid tunnel ad to distal radius.

58. SAMMARY
• Scaphoid serves as the connecting rod
between the proximal and distal carpal rows.
• And is stabilised by the scapholunate ligament
directly and lunotriquetral ligament indirectly.
• Disruption of either of this ligament leads to a
pattern instability that left untreated leads to
altered mechanics of wrist and ultimately
arthritis and collapse.

59. SUMMARY
• Arthroscopy is gold standard
• In acute setting conservaive treatmet may be
attempted.
• But recalcitrant cases require surgical
stabilisation.
• Salvage procedure are also available for those
patient who fail initial stabilisation.