Chapter 30 - Flexor and Extensor Tendon Injuries

Question 1

predominant collagen in tendon?

Answer 1

Type I collagen

Question 2

Phases of tendon healing: inflammatory phase

Answer 2

injury to 7days

infiltration of fibroblasts and macrophages

repair strength relies ENTIRELY on suture

Question 3

Proliferative phase of tendon healing

Answer 3

second phase 7-21 days

neovascularization occurring

fibroblasts deposit T III collagen (immature) - later gets replaced by type I

Question 4

remodeling phase of tendon healing

Answer 4

weeks 3-12

collagen fibers become reorganized along the length of the tendon

Question 5

mechanisms of tendon healing: extrinsic tendon healing

Answer 5

inflammatory cells and fibroblasts derived from tendon sheath

predominates when repair is immobilized

collagen deposition is disorganized

Question 6

mechanisms of tendon healing: intrinsic tendon healing

Answer 6

inflammatory cells and fibroblasts derived from within tendon and epitenon

predominates if motion rehab used post op

Question 7

diagnosing an FDS injury

Answer 7

inability to flex the PIP joint with the adjacent digits held in extension

Question 8

Zone III extensor tendon injuries indicate disruption of what structure?

Answer 8

central slip of the common extensor

positive elson test - inability to actively extend the PIP joint with the joint resting in 90degrees of flexion, or the DIP extends with attempted PIP extension

Question 9

Zone V extensor tendon injuries indicate disruption of what structure(s)

Answer 9

sagittal bands

loss of active mcp extension ans extensor tendon subluxation into valleys between mcp joints with MCP flexion

Question 10

What tendon lies ulnar - EDC or EIP?

Answer 10

EIP

Question 11

what tendon lies ulnar - EDM or EDC?

Answer 11

EDM

Question 12

What mm belly is the most distal in the fourth dorsal extensor compartment?

Answer 12

EIP

Question 13

when to repair a partial flexor tendon laceration

Answer 13

when more than 60% of the tendon is disrupted

Question 14

strength of a repair is directly proportional to what?

Answer 14

the number of core sutures in the repair (3-0 or 4-0 core suture usually)

Question 15

minimum number of core sutures required to allow active motion immediately post op?

Answer 15

4

Question 16

Jersey finger

Answer 16

Zone one flexor tendon injury - either avulsion of the FDP off the volar lip of the distal phalanx, or a fracture of the volar lip of the distal phalanx base

Question 17

Type I jersey finger

Answer 17

FDP retracted to palm - vincula are disrupted

recommend acute repair (<7-10 days post injury)

Question 18

Type II jersey finger

Answer 18

FDP to level of PIP (vincula intact)

repair within several weeks

Question 19

Type III jersey finger

Answer 19

attached to large avulsion fragment

Question 20

passive motion protocols for flexor tendon repair

Answer 20

kleinert - wrist at 45 flexion, rubber bands to the nails - actively extend fingers then rubber bands pull down slowly

duran - wrist at 20 degrees flexion - patient passively extends the DIP and PIP joints

Question 21

early active motion protocols

Answer 21

use dorsal blocking splint limiting wrist etension to neutral or slight flexion

moderate force and potentially high excursion

Question 22

synergistic motion regimen

Answer 22

low force, high tendon excursion

passive digit flexion with active wrist extension followed by active digit extension coupled with active wrist flexion

compared with passive motio regimen, active motion - less flexion contracture, increased joint motion, equivalent re-rupture rates

Question 23

when does repair re-rupture happen most frequently?

Answer 23

post op day 7-10

Question 24

zone I extensor tendon injury - mallet finger

Answer 24

forced hyperflexion of an extended dip

treat with full time extension splinting of DIP for 6-8 weeks

Question 25

Zone II extensor tendon injury (acute boutonniere deformity)

Answer 25

acute loss of PIP extension 2/2 central slip injury

mechanism: palmar dislocation of the pip joint

subsequent volar subluxation of the lateral bands causes DIP extension

TX; PIP extension splinting with DIP free

Question 26

lumbrical plus deformity

Answer 26

paradoxical extension of the IP joint of the injured digit with attempted flexion

caused by overlengthening of the fdp distal to lumbrical tendon - causes force of FDP to be transmitted to lumbrical (insertion on radial lateral band) rather than flexor