LT LIGAMENT INJURY AND VISI

Question 1

VISI definition

Answer 1

Form of CID associated with dysfunction of LTIL
Results in imbalance between SL and LT ligaments
Palmar flexion of lunate and scaphoid

Question 2

Anatomy of lunotriquetral interosseous ligament

Answer 2

C-shaped structure with dorsal, proximal, volar parts
Volar part thickest and strongest
Role in stability and proprioception = high concentration of mechanoreceptors like ACL

Question 3

Prerequisites for development of VISI

Answer 3

Secondary stabilisers must be defunctioned
Secondary stabilisers:
1. Volar radiolunate ligaments
2. Dorsal radiocarpal (radiotriquetral) ligament

Question 4

3 stages of LT dissociation

Answer 4

1. Stage I = partial injury
2. Stage II = complete injury with dynamic instability
3. Stage III = complete injury with static deformity

Question 5

Aetiology of LT ligament injury

Answer 5

Traumatic vs. atraumatic
Traumatic = FOOSH with wrist in extension/ radial deviation/ carpal pronation
Atraumatic
1. Inflammatory
2. Degenerative = attritional tears with positive UV
3. Infective

Question 6

4 main radiographic features of LT ligament injury on PA view

Answer 6

1. Piece of pie sign (wedge shaped lunate) = lunate flexion
2. Cortical/ signet ring sign = scaphoid flexion
3. Break in Gilula’s arcs
4. Generally no widening of LT interval

Question 7

4 main radiographic features of LT ligament injury on lateral view

Answer 7

1. SL angle < 30deg (normal = 30-60deg)
2. RL angle > 15deg volar (normal = 0 +/- 10deg)
3. ? CL angle
4. Spilled tea cup sign = lunate flexion

Question 8

Indications for non-operative management of LT ligament injury

Answer 8

1. Elderly low-demand patient
2. Asymptomatic
3. Partial tear
   Non-operative management has high failure rate

Question 9

3 factors to consider with surgical management of LT ligament injury

Answer 9

1. Acuity = repair vs. reconstruction
2. Correctability = reconstruction vs. fusion
   - Recon with PL tendon graft or ECU left attached distally has better outcomes than fusion
3. Arthritis = fusion
   - LT fusion has high nonunion rate
   - Radiolunotriquetral fusion