Tendon injury

Question 1

What pulleys arise from volar plate

Answer 1

A1, A3, A5 (A2 and A4 from periosteum)

Question 2

Thumb flexor zones and pulleys

Answer 2

Pulleys A1, Y-band (pars annular and oblique) and A2

Zone 1: A2 and distal
Zone 2: A1 and distal
Zone 3: proximal to A1

Question 3

What type of collagen in tendons?

Answer 3

Type 1 arranged in a longitudinal fashion

Collagen molecule> collagen fibril> collagen fiber> fiber bundle> 2ndary fiber bundle> tertiary fiber bundle> tendon unit with epitendon also surrounding units from fiber bundles

Question 4

How many vinculum does each tendon have?

Answer 4

Two
Brevis - close to insertion
Longus - proximal

Vascularization comes through the vincula

Question 5

Function of pulleys?

Answer 5

Annular: mechanical
Cruciate: nutrition

Question 6

3 phases of tendon healing?

Answer 6

Inflammatory phase 1 week (blood cloth, removal of debris)
Proliferative phase 1-3 weeks (fibroblast proliferation, typ 3 collagen, prone to rupture 10-12d)
Remodeling phase >6w (typ 1 collagen, never full strength 40-70%)

Question 7

How much pulley venting is possible

Answer 7

<2/3 of A2 or complete A4

Question 8

Zone 1 different subzones?

Answer 8

1a) Distal to A5
1b) A5, C3 and distal to A4
1c) A4 (overlap zone 2

Question 9

Classifiation FDP avulsion

Answer 9

Leddy Packer
type 1) retracted to palm, no vascularization (urgent, consider arthrodesis)
type 2) retracts to PIP (reinsertion
Type 3) Large fracture fragment, retracts to DIP, both vincula intact
Type 4) Double avulsion, fracture + avulsion from fragment
Type 5) Avulsion + comminuted fracture