Flexor Tendon Flashcards
the distal tendon insertions determine the
level offlexion
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The FDS and FDP tendons within the flexor tendon sheath receive
nutritional supply and eliminate wastes by two ways: vascular perfusion
and synovial diffusion.
well-developed vincular system, which takes off the
common digital arteries and continues to the dorsal aspectofthe tendon
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The palmar aspect ofthe tendon is relatively avascular,
and the paratenon promotes material exchange by means ofdiffusion
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The A2 and A4 pulleys originate from the periosteum of the proximal and middle phalanx, respectively. They are the most important pulleys in maintaining grip power and preventing bowstringing of the flexor tendons during active finger flexion.
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cruciate (Cl-C3) pulleys
They function to accommodate
full flexion and extension of the joints without significant collapse or
expansion ofthe adjacent annular pulleys during finger motion.
Zone I is the area
distal to the insertion of the FDS tendon only involving the FDP
tendon
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Zone 2 describes the area within the flexor tendon sheath
distal to the Al pulley but proximal to the FDS insertion;
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Zone 4 tendon injury
is rather uncommon because the overlying trapezium and hamate
prominence shield the tendons in this zone from laceration
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for smooth gliding and minimize peri tendinous adhesion Sometimes this
requires partial excision of the FDP tendon to decrease the repair
bulk,
F FDS
for smooth gliding and minimize peri tendinous adhesion Sometimes this
requires partial release of the adjacent pulleys
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In the setting of vascular compromise to the digit we repair the tendons concomitant with vascular injury
T microvascular repair or reconstruction to restore digital perfusion
are indicated, and the lacerated flexor tendons can be repaired at the
same time.
Beyond
6 weeks, the primary repair of flexor tendon is unlikely to succeed why?
because of myostatic contracture of the lacerated tendon and swelling of the tendon ends that do not permit tendons to be retrieved
through the pulleys
later experiments demonstrated the alternative intrinsic
tendon healing without adhesion
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increasing the suture caliber can increase the tensile strength at
the repair site.20 Similarly, an increased number of core strands also
increases repair strength
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core strand number is more important than suture caliber in terms
of increasing repair site strength.
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locking
core suture loops are stronger than grasping loops
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the location
of the core suture knot, inside or outside of the repair site, has not
been shown to affect the repair site strength
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Deeply
placed epitendinous sutures provide better repair strength compared to those placed superficially
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Epitendinous sutures placed
further from the cut edges also improve the tensile strength at the
repair site
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epitendinous sutures for Zone 2 are recommended in addition to the core sutures
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Epitendinoud repair placed at 2 mm from the cut edges and
2 mm deep
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a gap less than 3 mm is the critical gap to facilitate
adequate healing of the tendon and increased repair strength with
time
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Shortening of the FDP tendon by more than 1 cm is undesirable because of the quadriga effec
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When nonunion is present in the absence of scaphoid flexion,
screw fixation and autogenous distal radius cancellous bone grafting
can be performed via a dorsal or volar approach
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In type II avulsion, the FDP tendon
retracts to the level of the PIP joint, and can be repaired within
6 weeks from the time of injury
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type III injuries usually do not retract
proximal to the A4 pulley
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if the distal stump is Jess than
I cm in length may require tendon-tobone repair
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In delayed
presentation of Zone 1 injuries outside of the time window for repaire What is the treatment
DIP arthrodesis
If the proximal FPL tendon cannot be retrieved readily, we prefer to make an incision at the
wrist, radial to the FCR tendon
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epi tendinous sutures may not be necessary in zone 3.4.5 because there is more room in these zones for tendon excursion, which decreases the intensity of the
adhesions
T multiple structures are cut in these zones,
which require expedient repairs to keep the tourniquet time within
2 hours
Repairs in Zones 3, 4, and 5 have less adhesion formation
and better prognosis.
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Therapy should begin within a week of the surgery under the
guidance ofan experienced hand therapist
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Early motion rehabilitation protocol in the appropriate patients helps to decrease intrasynovial adhesion formation and prevent digital stiffness
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It has been well accepted that 3 to 5 mm of tendon excursion
sufficiently prevents adhesion formation in Zone 2 repairs
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increasing the level ofapplied
force during rehabilitation does not affect the ultimate strength ofthe
repaired tendon
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active place-and-hold therapy improved finger active
range ofmotion, compared to passive motion therapy, although functional outcome scores were similar in both groups
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More rigorous active finger range of motion starts at 3 to 4 weeks
postoperatively
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The protectivedorsalsplint iseventually discontinued
around 6 to 8 weeks postoperatively.
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Individual digit strengthening is
gradually introduced at 10 weeks after surgery,
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normal activities at 4 to 6 months after surgery
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In pediatric
patients and those who are unable to safely participate in an early
motion rehabilitation program, cast immobilization for 4 to 6 weeks
is used to protect the repair
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Zone 1 and Zone 2 repairs have good to excellent outcomes
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almost
all Zone 3, 4, and 5 repairs have good to excellent outcomes.
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Outcomes of flexor tendon repair
depends on multiple
factors,
severity ofinitial injury,
timing and quality of the repair,
patient’s underlying medical conditions that may affect tendon
healing, and the quality of postoperative rehabilitation
The most common complication is finger
stiffness, which can be a result ofeither tendon adhesion or IP joint
contractures
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total active motion (TAM) =
TAM= (MCP+PIP+DIP)flexion - extensionlag
a percentage of the normal TAM of 260°
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Normal TAM?
excellent outcome is the recovery of 100% of the normal TAM; a
good outcome is the recovery of more than 75% of the normal TAM
but less than 100%. A recovery ofless than 75% but more than 50% is
considered fair, and anything less than 50% is considered poor
At 4 to 6 months after the flexor tendon repair surgery, if a
patient’s digit function is no longer improving What you will do ?
If the active motion is an absent and passive motion has been restored need
tenolysis
Tenolysis recommended
only for patients with fair or poor outcomes
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Rupture within the first 3 weeks ofthe initial tendon repair
warrants an attempt for repeat repair, which has reasonable success
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Ifthe rupture occurs more than 3 weeks after the primary repair, tendon reconstruction should be considered
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IP
joint contractures management
passive stretching exercises and static progressive splinting Beyond 4 to 6 months after the
index procedure, joint releases to correct the contractures can be considered
TENDON RECONSTRUCTION INDICATIONS
flexor tendon injuries that have significant segmental tendon loss or damage
present late and outside ofthe time window for primary > 6 week
ruptures that occur after primary repair > 3 week
flexor tendon injuries require early intervention
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early protective motion therapy to promote healing and decrease adhesion formation
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In type I
avulsion, the FDP tendon retracts into the palm with disruption of
the vascular system, and thus needs urgent repair within 2 weeks from the time of injury
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However, tenolysis is a complicated
procedure that can result in neurovascular injury, worsening stiffness, and even tendon rupture
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