11: Tendon Healing and Rupture - Frush Flashcards
define tendon transfer
detachment of a tendon of a functioning muscle at its insertion and then its relocation to a new insertion or attachment
define tendon transposition
the rerouting of the course of a normal muscle tendon without detachment to assist other functions
define muscle-tendon transplantation
The detachment of a muscle tendon at both its origin and its insertion and moving it to a new location along with its neurovascular support structures constitute a muscle–tendon transplantation
define tendon suspension
Tendon procedures designed to support a structure (AKA tenosuspension)
histology % tendons
30% collagen
2% elastin
ECM - 68% water
polypeptide chain –> tropocollagen –>
filament –> fibril –> fiber –> subfascicle –> fascicle –> tendon
synovial layer surrounding tendon
epitenon
areolar tissue containing n and blood vessels
paratenon
epitenon + paratenon
mesotenon
when is a tendon sheath present?
when tendon angles around structures
paratenon vs. tendon sheath
Paratenon:
- Continuous with epitenon
- Contains nerve and blood vessels
- Allows tendon to glide
- Only found on tendons with straight pull, ie: Achilles tendon
Tendon Sheath:
- Tubular structure prevents bowstringing
- Lined with synovial cells
- Allows tendon to glide like a piston in a cylinder
- Epitenon and inner layer of sheath make up mesotenon
- Contains blood and lymphatics
point of attachment in mesotenon
hilus
what are plicae?
connective tissue doubled over on itself to provide free pistoning motion of the tendon, stretching and folding to protect the vital mesotenon from excessive tension
*** 3 sources vascular supply to tendon
- Musculotendinous junction
- Bone/periosteum
- Paratenon by way of hilus (***majority of supply)
where are sharpey fibers
at tendon attachment to bone
what happens at impact?
- moment of injury
- activation of complement cascade
- vasoconstriction
- platelet aggregation (intrinsic and extrinsic pathway activation)
- chemotaxis
what happens with inflammation phase?
- cellular infiltration
- jelly-like serous and granulation tissue at gap zone
- PMN’s and macrophages
- acidic environment with low oxygen tension stimulates fibroblast and collagen production
proliferative phase tendon healing?
- fibroblasts bridge gap zone
- collagen synthesis
- return of function
remodeling phase tendon healing?
- Healing
- systematic organization of collagen bundles with anatomic orientation
chronology of tendon healing week 1 - 4
week 1 = softening, production of jelly-like fibroblastic splint. strength of suture. tx immobilize.
week 2 = increased vascularity and proliferation of fibroblasts. strength suture. tx immobilize.
week 3 = vigorous production of collagen fibers. moderate bond strength. tx: gentle motion or isometric exercises.
week 4 = collagen fiber alignment; cleavage from local tissues. not quite full strenght. tx: progressive muscular foce.
tendon three and four months post injury
THREE MONTHS:
-Small collagen bundle
formation with anatomic
orientation
FOUR MONTHS:
-Larger collagen bundle
formation
-Normal tendon
m produces greatest force at …
120% resting length
zero tension found to be at 60% resting length
tension developed by m is related to length of m when contracts
*** i want to ... so i put the tendon limit motion rotate stabilize rotate and stabilize
- close to joint axis
- 90 degrees to joint axis
- parallel to bone and away from joint axis
- 45 degrees to joint axis
where are tendon fulcrums located?
sesamoids - FHB
cuboid - PL
increases angle of application and improves efficiency of tendon function
torque anterior v posterior leg
Ratio of torque produced by anterior versus posterior leg muscles in controlling foot function is 1:4
This is due in large part to long lever arm of forefoot vs. the short lever arm of triceps surae
how does phase relate to tendon transfer?
Muscles transferred in phase regain activity in 7 to 8 weeks
Out-of-phase tendon transfer can be done but takes a lot of retraining. Goal should be to regain function
swing phase: tibialis anterior ; extensor hallucis longus; extensor digitorum longus; peroneus tertius
stance phase: remaining
6 principles of tendon transfer
improve motor function
eliminate deforming forces
restore lost motor function
increase stability
eliminate need for bracing
improve cosmetic appearance
Muscle Grading System 5 4 4+ 4- 3 2 1 0
5 full resistance at end range of motion 4 some resistance at end range of motion 4+ moderate resistance at end range of motion 4 - mild resistance at end range of motion 3 able to move against gravity alone 2 able to move with gravity eliminated 1 can palpate or visualize m contraction 0 no evidence of m contraction
you will lose __ grade with transfer of tendon
Loss of 1 muscle grade with transfer of the tendon
anastomosis with most physiologic pull
side to side anastomosis
most common end to end suture repair
bunnel repair
- moderate strength, pull is longitudinal
- (-) constricts vascular supply to tendon
desgined after chinese finger trap
- lateral trap repair
- grips outside of tendon
- avoids constricting microcirculation
krackow repair
- end to end
- Interlocking weave stitch
- Good tensile strength
- Doesn’t constrict microcirculation
- Technically easy to perform
hibbs tenosuspension
cute EDL tendons and insert into midfoot to limit force on toes
jones would transfer to head of metatarsal
