Flexor tendon injuries

Flexor tendon
injuries
Birimong. CMC vellore MS ortho. 21/02/18
HAND SURGERY DEPARTMENT
3/18/2018 1Footer Text
Reference; Campbell's Operative Orthopaedics 12th edition

History;
• No repair possible in digits
• ‘ no man’s land”
• Current evidence
o 1970’s; repair is possible without delayed grafting, reconstruction
o Now; adhesion free, primary healed tendon repair is possible
3/18/2018Footer Text 2

anatomy
• FDP:
• Origin; antero medial ulna, IO membrane
• Four tendon from common belly

anatomy
• FDS:
• Origin; 2 heads. radius and ulnar
heads
• Divided muscle belly in mid forearm

Zones of flexor tendons in
hand

insertion
• PDS divided into two slips, wrapping around FDP,
reunite at Camper’s chiasma
• Continues to insert along the proximal half of the middle
phalynx

insertion
• PDP passes through chiasma to insert at proximal base
of distal phalynx
• Primary flexor
• Combines with intrinsics

sheaths
• Visceral and parietal synovial layers encloses the
tendons
• Pulleys; A2 and A4 arise from periosteum of proximal
and middle phalynx

nutritions
• 2 sourses;
• Vascular;
o longitudinal vessels in the
paratenon,
o intraosseous vessels at the
tendon insertion, and
o vincular circulation
• synovial

Zones of ischaemia
• ischemic area is present in the ﬂexor digitorum
superfcialis beneath the A2 pulley at the proximal
phalanx.
• Two zones of ischemia are present in the ﬂexor
digitorum profundus— beneath the A2 pulley and
beneath the A4 pulley

Examination of injured
flexors
• Careful examination of the neurovascular status of the
hand precedes the evaluation of tendon function.
• Even when gross deformity is absent, the posture of the
hand often provides clues as to which ﬂexor tendons are
severed.
• Traditionally, the “finger points the way” toward the
injured structures.

Examination of injured
flexors
• When both flexor tendons of a finger are severed, the
finger lies in an unnatural position of hyperextension,
especially compared with uninjured fingers.

examination
• Flexor tendon injuries can be tentatively confirmed by several
passive maneuvers;
• Passive extension of the wrist does not produce the normal
“tenodesis” flexion of the fingers.
• If the wrist is flexed, even greater unopposed extension of the
affected finger is produced.
• Gentle compression of the forearm muscle mass at times shows
concomitant flexion of the joints of the uninvolved fingers.
• Gently pressing the fingertip of each digit reveals loss of normal
tension

examination
• With the proximal interphalangeal
joint stabilized, the flexor digitorum
profundus is presumed
severed if the distal interphalangeal
joint cannot be activelyflexed. (B)
• If neither the proximal nor the distal
interphalangeal joint can be actively
flexed with the metacarpophalangeal
joint stabilized, both flexor tendons
probably are severed.

examination
• The method used to show the
transection of FDS with an intact FDP
involves maintaining the adjacent fingers
in complete extension, anchoring the
profundus tendon in the extended
position, and removing its inﬂuence from
the proximal interphalangeal joint.
• When a ﬂexor superfcialis tendon has
been severed, and the two adjacent
fingers are held in maximal
extension,flexion of the interphalangeal
joint usually is impossible

examination
• Exception is the result of the independent function of the
index
finger FDP
• a technique advocated by Lister is helpful.
• the patient is requested to pinch and pull a sheet of paper with
each hand, using the index fingers and thumbs. In the intact
finger, this function is accomplished by the FDS .
• If a wound is located at the level of the wrist, the joints of a
finger can be actively flexed even though the tendons to that
finger are severed. This is the result of intercommunication of
the flexor profundus tendons at the wrist, particularly in the
little and ring fingers

Tendon healing;
• Extrinsic and intrinsic mechanisms,
• Three phases:
o inﬂammatory (48 to 72 hours),
o fibroblastic (5 days to 4 weeks), and
o remodeling (4 weeks to about 3.5 months).
• Predominance of extrinsic over intrinsic healing leads to
more adhesions
•

Tendon healing;
• Experiments suggest that cyclic tension applied to
healing tendons stimulates the intrinsic healing response
more than does the lack of tension.
• Techniques to prevent adhesion formation include the
use of physical barriers and chemical agents. None has
proved reliable in the clinical setting.
• Cytokine manipulation, gene therapy, and mesenchymal
stem cell therapies are other areas of promising
research into methods of controlling the formation of
adhesions.

Goals of repair
• Sufficient strength for passive motion rehab which will
allow for;
o Minimum adhesion formation
o Restoration of gliding surface
o Fascilitation of repair site healing

Strickland Criteria;
• Strickland stressed six characteristics of an ideal tendon
repair:
o (1) easy placement of sutures in the tendon,
o (2) secure suture knots,
o (3) smooth juncture of tendon ends,
o (4) minimal gapping at the repair site,
o (5) minimal interference with tendon vascularity, and
o (6) sufficient strength throughout healing to permit application of early motion stress to
the
tendon.
• In general, studies have shown that four-strand core
suture with epidermis repair best accomplishes these
objectives.

Suture materials
• In a biomechanical study, braided polyethylene and braided
stainless steel wire were most suitable mechanically.
• Braided polyester was intermediate, and monoflament sutures
of nylon and polypropylene were least satisfactory
• a 3-0 suture in a two-strand or four-strand confguration is
recommended if an early active motion program is used.
• Epitendinous repair usually is done with 5-0 or 6-0
monoflament suture (Prolene).

Types of repairs;
• three groups ;
• Group 1 is exemplifed by
simple sutures; the suture
pull is parallel to the
tendon collagen bundles,
transmitting the stress of
the repair directly to the
opposing tendon ends.
•

Types of repairs;
the Bunnell suture; stress
is transmitted directly
across the juncture by the
suture material and
depends on the strength of
the suture itself.
•

Types of repairs;
the Pulvertaf
technique (fish-mouth
weave); sutures are
placed perpendicular to
the tendon collagen
bundles and the applied
stress.

Types of repairs;
• Interrupted sutures were found to be the weakest and
unsuitable in most tendon repairs.
• fish-mouth or end-weave repairs are the strongest and
are most suitable for tendon graft and tendon transfer
junctures in the distal forearm and palm areas,

McLarney stitch
• simple and easy to perform, yet strong enough to
withstand the projected forces of an
in vivo active motion rehabilitation protocol
• Forty human cadaveric flexor digitorum profundus
tendons were divided and repaired using 1 of 4 suture
techniques (the modified Kessler,
the Strickland, the modified 4-strand Savage, and the
Cruciate 4-strand repairs).

McLarney stitch

McLarney stitch
• The Cruciate suture technique was demonstrated to be
nearly twice as strong to 2-mm gap
formation (44 N).
• Ultimate tensile strength was also significantly stronger
for the Cruciate technique (56 N)
• The technique was significantly faster to perform

• Most investigators report that the strength of the tendon
repair diminishes considerably in the first 10 days.
• Thereafter, the strength of the repair gradually increases,
so that by the end of 10 to 12 weeks considerable active
forces can be applied
in the rehabilitation program.

Exposures;

Timing of repair
• a primary tendon repair is done within the first 12 hours of
injury.
• delayed primary repair is one that is done
within 24 hours to approximately 10 days.
• After 10 to 14 days, the repair is considered to be secondary;
• and after about 4 weeks, the secondary repair is a “late”
secondary repair
• Basic science and clinical evidence suggest
that it is preferable to perform tendon repair early after
injury. - * Greens operative hand surgery

Partial tendon
lacerations;
• After partial tendon lacerations, complications reported
by many authors include rupture, triggering, and tendon
entrapment.
• A tendon with
60% laceration can retain 50% or more of strength,
90% laceration can retain only slightly more than
25% of its strength.
• Studies in human cadaver tendons found that loads
required to rupture 50% and 75% tendon
lacerations were higher than the physiological loads
measured during normal active motion.

Partial tendon
lacerations;
• In canine ﬂexor tendons with lacerations of 30% and 70% of
the cross-sectional area, with and without repair, no signifcant
diﬀerences were seen
• suggesting that partial lacerations of 70% of
the cross-sectional area could be treated without repair
• If a tendon is lacerated 60% or more, it is treated the
same as a complete transection.
• If the laceration is less than 60%, the injury is evaluated
for the risk of triggering.

Zone 1 injuries
• If the tendon is lacerated, and the distal tendon stump is
less than 1 cm long, FDP tendon advancement and
primary repair to bone is usually indicated.
• If more than 1 cm of FDP stump is available for suture,
primary tenorrhaphy is usually done because shortening
of the FDP tendon by greater than
1 cm may result in a “quadrigia” effect

classification
• Leddy and Packer ; Profundus
avulsion classification
• Type I: FDP tendon is avulsed from
its insertion and retracts into the
palm
• Type II: The profundus tendon is
avulsed from its insertion, but the
stump remains within the digital
sheath, implying that the vinculum
longum profundus is still intact.
• Type III: A bony fragment is attached
to the tendon stump, which remains
within the flexor sheath.
3/18/2018Footer Text 36Greens operative hand surgery . 6th edition

Zone 1 injuries
• Leddy type I injuries require early (within 3 weeks)
diagnosis and treatment.
• Although all ﬂexor tendon avulsion injuries are best
treated early, Leddy type II and III injuries may be
amenable to later repair.

Zone 1 injuries
• Direct tendon repair is preferable if
there is at least
1 cm of distal tendon stump.
• Tendon repair to bone is done if there is
less than
1 cm of distal tendon stump. Either
suture anchors or
pull-out suture and button constructs
may be used.
• tendon-bone site should be observed
directly
before final knot-tying to ensure the
tendon is well
seated on the repair footprint (distal
phalanx).

Zone 1 injuries
• Leddy type I injuries require early (within 3 weeks)
diagnosis and treatment.
• Although all ﬂexor tendon avulsion injuries are best
treated early, Leddy type II and III injuries may be
amenable to later repair.
• Although satisfactory function can be achieved, limitation
of distal interphalangeal joint motion is to be expected,
regardless of the level of
rupture.

Zone II
• Primary repair in the fibroosseous sheath (Bunnell’s “no
man’s land”), which was controversial until the major
contributions of Verdan and of Kleinert, is now widely
accepted
• Primary repairs at this level frequently fail because of
adhesions in the area of the pulleys.
• Exacting wound care is crucial.
• If the timing of tendon repair is in doubt, the wound
should be cleaned and the repair made later by an
experienced surgeon.

Zone II
• Routine tendon repairs are preferably done no later
than 7 days after injury.
• After 6 weeks, primary repair is unlikely to be possible

Zone II
• In zone II, a core suture with two or more strands,
locking components, and buried knots is usually
preferred.
• A running, circumferential 5-0 or 6-0 nylon is used by
most surgeons to complete a smooth repair and to
minimize adhesion formation to the sheath and
“triggering” on the sheath.

Zone III
• At zone III, the muscle bellies of the lumbricals and the
tendons frequently are interrupted.
• If conditions permit, primary repair of sharply severed
nerves is crucial because delaying the repair even a few
weeks results in significant gaps between the nerve
ends.
• If wound conditions preclude tendon and nerve repair,
the ends of the tendons and nerves are sutured to
adjacent fascia to prevent undue retraction

Zone III
• Lumbrical muscle bellies usually are not sutured
because this can increase the tension of these muscles
and result in a “lumbrical plus” finger (paradoxical
proximal interphalangeal extension on attempted active
fingerflexion).

Zone IV, V
• All tendons and nerves in zone IV can be repaired
primarily when wound conditions are satisfactory
• Because zone V is proximal to the transverse carpal
ligament, tendon gliding after repair usually is better here
than in more distal zones

Post op care; in CMC Vellore
• The wrist usually is positioned in 30 degrees of ﬂexion
with the metacarpophalangeal joints in 60 to 70 degrees
of ﬂexion and interphalangeal joints left in extension.
• Beginning on the 2nd or 3rd day after surgery, flexion
outrigger traction device is applied and active extension
exercises within the limitations of the splint are
encouraged.

• Stage 1; 0-4 weeks
• Encourage active extion of fingers hold for 10 counts ans
rubber bands to passively flex the fingers. 10 repetitions every
hour.
• Make sure PIP joint contracture doesnot develop
• StageII; 4-6 weeks
• Supervised active flexion
• Encourage to do active flexion and extension infront of
therapist and retain FOT traction

• Stage III; 6-8 weeks;
• Bivalve cast, suture removal, dorsal POP slab
• Active flexion and extension within the slab
• Each day increase 10 degrees of extension by breaking
the slab at MCP joint
• Isolation of FDS and FDP exercises using Bunnell’s
block

• Stage IV; 8-10 weeks;
• Volar cock up splint, wrist in neutral
• Encourage active flexion and extension of all fingers
within the splint
• Light activities
• Home self care

• postoperative management is paramount,
• Tenolysis may be required in an estimated 18% to 25%
of patients after flexor tendon repair.

Flexor tendon injuries

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