VISI

 

Definition

 

Volar Intercalated Segmental Instability (VISI) secondary to injury to the lunate-triquetral ligament

 

Etiology

 

FOOSH

 

Anatomy

 

Lunate-triquetal ligament C shaped and strongest palmar

- scaphoid imparts a flexion moment on proximal row

- triquetrum imparts an extension moment

- balanced by ligamentous attachments to lunate

 

Pathology

 

Tear lunate-triquetral ligament and get palmarflexion of lunate with dorsiflexion of triquetrum

 

Classification

 

CID	CIND VISI
Static Dynamic	Ligamentous laxity in teenage girls Entire proximal row is flexed  Lunate triangular / scaphoid cortical ring sign
	Wrist clunking Non operative

 

Symptoms

 

History of injury 

Pain on ulnar side of wrist 

Weakness 

 

Signs

 

Swelling and tenderness over triquetro-lunate joint 

Pain with ulna deviation / pronation / axial compression

 

Reagan Ballotment 

- Triquetro-lunate ballottement

- pisiform-triquetral with thumb and index finger

- lunate with other hand

 

 

Differential diagnosis

 

DRUJ instability

TFCC tear

Ulna head OA

Pisiform triquetral OA

Hamate fracture

ECU subluxation

 

Xray

 

AP xray

- palmarflexion of scaphoid - Scaphoid shortened + cortical ring sign 

- palmarflexion of lunate  - appears triangular 

- broken Shenton's line (of proximal carpal row)

 

Lateral xray

- decreased scapholunate angle < 30^o

- palmarflexion of lunate: capitate - lunate angle > 10^o / radio - lunate angle > 10^o

 

Operative management

 

Options

 

Repair

Reconstruct with ECU

Lunate - triquetral fusion

 

Technique

 

Dorsal approach

- restore LT orientation with K wires

- repair ligament with intra-osseous sutures

- +/- reconstruct with half of ECU through drill holes

 

Lunate-triquetral fusion