15. Principles of Tendon Healing

Question 1

what are the 3 vascular sources to a tendon?

Answer 1

1. musculotendinous junction
2. bone/periosteum interface
3. paratenon by way of hilus **majority of supply

Question 2

what are the phases of tendon healing?

Answer 2

1. impact
2. inflammatory
3. proliferative
4. remodeling

Question 3

when does bridging of the gap occur?

Answer 3

week 2 (10-14 days)

Question 4

what tendons are active in the swing phase of gait cycle?

Answer 4

tibialis anterior
EHL
EDL
peroneus tertius

Question 5

how long does it take for an in-phase tendon transfer to regain activity? vs. out-of phase?

Answer 5

in phase: 7-8 wks

out of phase: 1-2 yrs

Question 6

Describe the building blocks of tendon anatomy.

Answer 6

tropocollagen –> collagen filament –> fibrils –> fiber –> fasicle

Question 7

what does an endotenon surround?

Answer 7

envelopes a group of fasicles

Question 8

what does an epitenon surround?

Answer 8

the tendon

Question 9

what is a mesotenon?

Answer 9

epitenon + paratenon

Question 10

what is a paratenon?

Answer 10

continuous with the epitenon, contains nerve and blood vessels

Question 11

what is the difference btwn paratenon and tendon sheath?

Answer 11

tendon sheaths are found in tendons that change direction

paratenon is found in tendons w/ straight pull aka achilles tendon

Question 12

what is a hilus?

Answer 12

point of attachment of mesotenon to tendon to provide bloodflow

Question 13

what is plicae?

Answer 13

CT doubled over on itself to provide free pistoning motion of the tendon, stretching and folding to protect the vital mesotenon from excessive tesnion

Question 14

What happens on a cellular level in the impact phase of tendon healing?

Answer 14

• complement cascade is activated
• vasoconstriction
• platelet aggregation
• chemotaxis

Question 15

What is the timescale for inflammatory phase?

Answer 15

48-72 hours

days 2-3

Question 16

What happens on a cellular level in the inflammatory phase of tendon healing?

Answer 16

• cellular infiltration: PMN, macrophage
• jelly-like serous and granulation tissue at gap zone
• acidic environment (low O2 tension) stimulates fibroblast and collagen production

Question 17

what is the time scale of proliferative phase of tendon healing?

Answer 17

5 days

Question 18

what occurs in the proliferative phase of tendon healing?

Answer 18

• fibroblasts bridge gap zone
• collagen synthesis
• return of function

Question 19

What is the timescale for remodeling phase?

Answer 19

15-28 days

Question 20

what occurs in the remodeling phase?

Answer 20

• healing

- systematic organization of collagen bundles with anatomic orientation

Question 21

When can you start some active/passive ROM?

Answer 21

week 3

Question 22

when can an athlete return to high impact sports?

Answer 22

month 4

Question 23

Describe the healing process of tendon on a timeline.

Answer 23

Week 1- opposed tendon ends join thru a gelatinous bridge of serous and granulation tissue
Week 2- vascularity is restored and collagen proliferates; gap is bridged
week 3- collagen fibers coalesce and align longitudinally; moderate tendon strength
week 4- reduced edema and vascular proliferation
month 3- small collagen bundle formation
month 4- larger collagen bundle formation

Question 24

a sarcomere at rest is what % of muscle length?

Answer 24

60%

Question 25

a sarcomere at max tension is at what % of muscle length?

Answer 25

120%

Question 26

At what % of resting length does muscle produce its greatest force?

Answer 26

120% *zero tension is found to be at 60% resting length

Question 27

what is a transposition tendon surgery?

Answer 27

rerouting the tendon without detachment

Question 28

What happens when a tendon is close to its joint axis?

Answer 28

there is limited motion (the tendon will not move that join)

Question 29

what happens when the tendon is 90 degress to the joint axis?

Answer 29

it will rotate that joint

Question 30

what will stabilize a joint?

Answer 30

- when a tendon is parallel to bone | - when a tendon is away from its joint axis

Question 31

what happens when a tendon is 45 deg to joint axis?

Answer 31

will rotate and stabilize the axis

Question 32

give two examples of tendon fulcrum in teh body.

Answer 32

sesamoids- FHB | cuboid- peroneus longus

Question 33

compare the torque produced by the anterior vs. posterior leg muscles?

Answer 33

torque of achilles tendon (posterior muscles) is 4x more than the anterior muscle group.

Question 34

what are teh goals of tendon transfer?

Answer 34

1. improve motor fxn 2. eliminate deforming forces 3. restore lost motor fxn 4. increase stability 5. eliminate need for bracing 7. improve cosmetic appearance

Question 35

What are some ways to fixate a tendon?

Answer 35

- side to side anastomosis (gives you the most physiologic pull) - end to end - tendon to bone

Question 36

give some types of end-to-end repair

Answer 36

Bunnell lateral trap kessler krackow

Question 37

what is teh end-to-end bunnell repair?

Answer 37

most common end-to-end suture repair - allows moderate strength; pull is longitudinal - disadvtg: constricts vascular supply to tendon.

Question 38

describe the end-to-end lateral trap repair.

Answer 38

grips outside of tendon | *avoids constricting microcirculation (as seen in Bunnell end-to-end repair)

Question 39

describe the end-to-end krackow repair.

Answer 39

- interlocking weave stitch - good tensile strength - doesn't constrict microcirculation - technically easy to perform.

Question 40

What are the options for tendon to bone repair?

Answer 40

``` Trephine plug interference screw button anchor screw and washer suture anchor ```

Question 41

what is the Z-tendon lengthening commonly used in?

Answer 41

EDL for contracted digits

Question 42

Name the tendon augmentation products.

Answer 42

graft jacket restore pegasus cadaveric graft

Question 43

what tendon transfer would you use for a contracted digit?

Answer 43

split FDL transfer

Question 44

what tendon transfer would you use for PTT dysufnction (flatfoot deformity)?

Answer 44

FDL transfer

Question 45

what tendon transfer would you use for an achilles tendon rupture?

Answer 45

FHL transfer

Question 46

what foot indications is a Hibbs tenosuspension for?

Answer 46

for flatfoot, metatarsal equinus, cavus foot

Question 47

what is the hibbs tenosuspension procedure?

Answer 47

EDL detached distally, combined & transferred to base of 3rd Met or 3rd cuneiform, stumps are anastamosed to EDB

Question 48

what is the Jones tenosuspension indicated for?

Answer 48

flexible plantarflexed 1st met

Question 49

what is the Jones tenosuspension procedure?

Answer 49

EHL transected at IPJ, rerouted medial to lateral, sutured back on itself, with IPJ arthrodesis