CHAPTER 12: WRIST

Question 1

What wrist injuries are commonly encountered?

Answer 1

Carpal Instabilities – SL and LT
Carpal Dislocations – Lunate and Perilunate
Carpal Fractures – Scaphoid

Question 2

What is a DISI and VISI deformity?

Answer 2

• SL ligament pulls lunate volarly
• LT ligament is pulls lunate dorsal.
• SL is weaker, so more likely to be injured

VISI – Volar Intercalated Segment Instability

• LT ligament problem
• if damaged lunate and scaphoid deviated volarly

DISI - Dorsal Intercalated Segment Instability
- SL Ligament problem
- lunate and triquetral are deviated dorsally
→ Terry Thomas Sign
- Use Clench-Fist view to see dynamic SL disassociation.

Question 3

What is a SLAC wrist?

What is the Watson shift test?

Answer 3

DISI deformity left → OA → SLAC (Scapho-lunate advanced collapse)

Watson shift test
- In ulnar deviation, the scaphoid has lots of space to sit un-flexed
- Radial deviation squeezes scaphoid into flexion.
- SL ligament stops it from completely flexing and popping out dorsally
– if SL ligament is disrupted → ‘pop’ and feel scaphoid dorsally

Question 4

What is SLAC Arthrodesis?

Answer 4

Scaphoid Excision and Four Corner Fusion of Lunate = Capitohamatotriquetrolunate fusion

Question 5

Perilunate and lunate dislocation

Answer 5

Perilunate Dislocation / Instability
- normally Radius, Lunate & Capitate lie in a row

Lunate Dislocation
- surgical emergency - lunate and haematoma impinge on median nerve → needs urgent decompression

Question 6

How do you describe scaphoid fractures?

What is a SNAC wrist?

Answer 6

‘SUDE’: 
Stable 
Unstable 
Displaced 
Established Non-Union 

SNAC - Scaphoid non-union advanced collapse

Question 7

What are Gilula’s lines?

Answer 7

Proximal edge of distal row
Distal edge of proximal row
Radio-carpal

Question 8

What are the differential diagnoses of radial wrist pain?

Answer 8

1. Intersection syndrome
2. FCR Tendinitis
3. DeQuervain’s
4. Scaphoid – Fracture-SNAC, SL Tear-SLAC
5. CMCJ – OA base of thumb
6. Sup branch rad nerve
7. ?Trigger
8. STT OA

Question 9

What are the differential diagnoses of central wrist pain?

Answer 9

1. Kienbock’s Disease - associated with -ve ulnar variance
2. Ganglion (SLL tear)
3. Carpometacarpal Boss

Question 10

What are the differential diagnoses of ulnar wrist pain?

Answer 10

1. Ulnar-carpal impingement - associated w +ve ulnar variation
2. TFCC tears
3. Piso-triquetral arthritis
4. Fractured hook of hamate

Question 11

What is the function of TFCC?

Answer 11

Stabilises DRUJ, supports ulnar carpus

Palmer Classification - Essentially:
Class 1 - Traumatic tear - A, B, C, D
Class 2 - Degenerative - A-E

1A Central perforation
1B Ulnar avulsion +/- distal ulnar fracture
1C Distal avulsion
1D Radial avulsion +/- sigmoid notch fracture
2A TFCC wear
2B TFCC wear + lunate / ulnar chondromalacia
2C TFCC perforation + lunate / ulnar chondromalacia
2D C+ L-T ligament perforation
2E D+ ulnocarpal arthritis

Question 12

What is Kienbocks disease?

Answer 12

Lunatomalacia - AVN of dorsal pole of lunate

Question 13

How does Kienbocks present?

Answer 13

Painful stiff swollen wrist
Young active adult
M:F 3:1
Unilateral, Dominant
stress fracture
Assoc w ulnar minus variance 
23% normal and 78% Kienbock’s have ulnar negative variance

Question 14

How do you diagnose Kienbock’s disease?

Answer 14

X-ray
CT
MRI
Bone Scan

Question 15

What are the treatment options?

Answer 15

Clinical stage v Rx (Lichtman)
I +ve bone scan & normal x-ray = immobilise
II sclerotic x-ray = radial shortening to get neutral variance
III lunate collapse x-ray = shorten radius + resect lunate + tendon interposition
IV carpal arthritis = proximal row carpectomy or wrist fusion

Question 16

What is ulnar variance?

Answer 16

Horizontal line drawn from junction of the distal articular surface and sigmoid notch of the radius (curve that articulates with ulna)

+ve variance = ulnar head above this line
→ ulnar impingement syndrome
-ve variance = ulnar head below this line
→ Kienbock’s disease, SL dislocation

Question 17

How is SNAC wrist classified?

Answer 17

Stage I: Arthritis localised to distal scaphoid and radial styloid

Stage II: Radioscaphoid + scaphocapitate arthritis, but preservation of lunocapitate joint

Stage III: Periscaphoid arthritis involving radiostyloid, distal scaphoid, scaphocapitate, and lunocapitate joints

Question 18

What is the treatment for different stages of SNAC wrist?

Answer 18

Stage I: radial styloid
- radial styloid excision + bone graft of scaphoid nonunion

Stage II: radioscaphoid, scaphocapitate

• proximal scaphoid fused to capitate and lunate with excision of distal scaphoid (Viegas)
• scaphoid excision, four-corner fusion

Stage III: radioscaphoid, scaphocapitate, lunocapitate

• scaphoid excision, four corner fusion
• wrist arthrodesis

Question 19

What is a SLAC and SNAC wrist?

Answer 19

• scapho-lunate rupture → SLAC wrist

- scaphoid fracture → SNAC wrist