15. Principles of Tendon Healing Flashcards
what are the 3 vascular sources to a tendon?
- musculotendinous junction
- bone/periosteum interface
- paratenon by way of hilus **majority of supply
what are the phases of tendon healing?
- impact
- inflammatory
- proliferative
- remodeling
when does bridging of the gap occur?
week 2 (10-14 days)
what tendons are active in the swing phase of gait cycle?
tibialis anterior
EHL
EDL
peroneus tertius
how long does it take for an in-phase tendon transfer to regain activity? vs. out-of phase?
in phase: 7-8 wks
out of phase: 1-2 yrs
Describe the building blocks of tendon anatomy.
tropocollagen –> collagen filament –> fibrils –> fiber –> fasicle
what does an endotenon surround?
envelopes a group of fasicles
what does an epitenon surround?
the tendon
what is a mesotenon?
epitenon + paratenon
what is a paratenon?
continuous with the epitenon, contains nerve and blood vessels
what is the difference btwn paratenon and tendon sheath?
tendon sheaths are found in tendons that change direction
paratenon is found in tendons w/ straight pull aka achilles tendon
what is a hilus?
point of attachment of mesotenon to tendon to provide bloodflow
what is plicae?
CT doubled over on itself to provide free pistoning motion of the tendon, stretching and folding to protect the vital mesotenon from excessive tesnion
What happens on a cellular level in the impact phase of tendon healing?
- complement cascade is activated
- vasoconstriction
- platelet aggregation
- chemotaxis
What is the timescale for inflammatory phase?
48-72 hours
days 2-3
What happens on a cellular level in the inflammatory phase of tendon healing?
- cellular infiltration: PMN, macrophage
- jelly-like serous and granulation tissue at gap zone
- acidic environment (low O2 tension) stimulates fibroblast and collagen production
what is the time scale of proliferative phase of tendon healing?
5 days
what occurs in the proliferative phase of tendon healing?
- fibroblasts bridge gap zone
- collagen synthesis
- return of function
What is the timescale for remodeling phase?
15-28 days
what occurs in the remodeling phase?
- healing
- systematic organization of collagen bundles with anatomic orientation
When can you start some active/passive ROM?
week 3
when can an athlete return to high impact sports?
month 4
Describe the healing process of tendon on a timeline.
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
a sarcomere at rest is what % of muscle length?
60%
a sarcomere at max tension is at what % of muscle length?
120%
At what % of resting length does muscle produce its greatest force?
120%
*zero tension is found to be at 60% resting length
what is a transposition tendon surgery?
rerouting the tendon without detachment
What happens when a tendon is close to its joint axis?
there is limited motion (the tendon will not move that join)
what happens when the tendon is 90 degress to the joint axis?
it will rotate that joint
what will stabilize a joint?
- when a tendon is parallel to bone
- when a tendon is away from its joint axis
what happens when a tendon is 45 deg to joint axis?
will rotate and stabilize the axis
give two examples of tendon fulcrum in teh body.
sesamoids- FHB
cuboid- peroneus longus
compare the torque produced by the anterior vs. posterior leg muscles?
torque of achilles tendon (posterior muscles) is 4x more than the anterior muscle group.
what are teh goals of tendon transfer?
- improve motor fxn
- eliminate deforming forces
- restore lost motor fxn
- increase stability
- eliminate need for bracing
- improve cosmetic appearance
What are some ways to fixate a tendon?
- side to side anastomosis (gives you the most physiologic pull)
- end to end
- tendon to bone
give some types of end-to-end repair
Bunnell
lateral trap
kessler
krackow
what is teh end-to-end bunnell repair?
most common end-to-end suture repair
- allows moderate strength; pull is longitudinal
- disadvtg: constricts vascular supply to tendon.
describe the end-to-end lateral trap repair.
grips outside of tendon
*avoids constricting microcirculation (as seen in Bunnell end-to-end repair)
describe the end-to-end krackow repair.
- interlocking weave stitch
- good tensile strength
- doesn’t constrict microcirculation
- technically easy to perform.
What are the options for tendon to bone repair?
Trephine plug interference screw button anchor screw and washer suture anchor
what is the Z-tendon lengthening commonly used in?
EDL for contracted digits
Name the tendon augmentation products.
graft jacket
restore
pegasus
cadaveric graft
what tendon transfer would you use for a contracted digit?
split FDL transfer
what tendon transfer would you use for PTT dysufnction (flatfoot deformity)?
FDL transfer
what tendon transfer would you use for an achilles tendon rupture?
FHL transfer
what foot indications is a Hibbs tenosuspension for?
for flatfoot, metatarsal equinus, cavus foot
what is the hibbs tenosuspension procedure?
EDL detached distally, combined & transferred to base of 3rd Met or 3rd cuneiform, stumps are anastamosed to EDB
what is the Jones tenosuspension indicated for?
flexible plantarflexed 1st met
what is the Jones tenosuspension procedure?
EHL transected at IPJ, rerouted medial to lateral, sutured back on itself, with IPJ arthrodesis
