Flexor and extensor tendon injury

Flexor and extensor tendon
injury

Tendon nutrition
• (1) the synovial fluid produced within the tenosynovial sheath and
(2) the blood supply provided through
• longitudinal vessels in the paratenon,
• intraosseous vessels at the tendon insertion, and
• vincular circulation

Ischemic area
• flexor digitorum superficialis
• 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

Tendon healing
• extrinsic : The extrinsic mechanism occurs through the activity of
peripheral fibroblasts and seems to be the dominant mechanism
contributing to the formation of scar and adhesions
• intrinsic mechanisms: Intrinsic healing seems to occur through the
activity of the fibroblasts derived from the tendon.
• occurring in three phases:
• inflammatory (48 to 72 hours),
• fibroblastic (5 days to 4 weeks), and
• remodeling (4 weeks to about 3.5 months

Adhesions
• tendon injury alone is insufficient to produce adhesions, whereas
tendon injury with injury to the synovial sheath combined with
immobilization leads to extensive adhesions.
• cyclic tension applied to healing tendons stimulates the intrinsic
healing response more than does the lack of tension. Findings such
as these have led to the development of postoperative mobilization
techniques to diminish the formation of adhesions and enhance the
end result.

• When both flexor tendons of a finger are severed, the finger lies in an
unnatural position of hyperextension, especially compared with
uninjured fingers.
• 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, whereas the injured finger does not
show this flexion, indicating separation of the tendon ends.
• Gently pressing the fingertip of each digit reveals loss of normal tension in the
injured finger.

Index finger examination
• The exception to this evaluation is the result of the independent function
of the index finger flexor digitorum `superficialis;
• a technique advocated by Lister is helpful in evaluating an isolated injury
to this tendon.
• In this examination, 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 flexor
superficialis with the flexor digitorum profundus relaxed, allowing
hyperextension of the distal interphalangeal joint so that maximal pulp
contact occurs with the paper.
• If the flexor superficialis is injured, the distal interphalangeal joint
hyperflexes, and the proximal interphalangeal joint assumes an extended
position.

Wrist wound
• 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.

Strickland stressed six characteristics of an
ideal tendon repair:
• (1) easy placement of sutures in the tendon,
• (2) secure suture knots,
• (3) smooth juncture of tendon ends,
• (4) minimal gapping at the repair site,
• (5) minimal interference with tendon vascularity, and
• (6) sufficient strength throughout healing to permit application of
early motion stress to the tendon.

Suture
• braided polyester sutures (Ticron, Mersilene,fibrewire) provide
• sufficient resistance to disrupting forces and gap formation,
• handle easily, and
• have satisfactory knot characteristics;
• 3-0 suture in a two-strand or four-strand configuration if an early
active motion program is used.
• In most situations, a 3-0 suture may be useful to repair tendons in
the forearm, palm, and larger digits, whereas a 4-0 suture may
handle better in smaller digits.

Urbaniak
• Group 1 is exemplified 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.
• Group 2 is exemplified by the Bunnell suture; stress is transmitted
directly across the juncture by the suture material and depends on the
strength of the suture itself.
• Group 3 is exemplified by the Pulvertaft technique (fish-mouth weave);
sutures are placed perpendicular to the tendon collagen bundles and the
applied stress.
• The 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

• 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.

Epitendinous sutures :epitenon-first technique
• Continuous epitendinous sutures, placed circumferentially around
the repair site, decrease the bulk of the repair site, minimizing the
risk of triggering.
• This addition also enhances the strength of the core suture repair,
supports 50% of the load to failure, and resists gap formation.

End to end sutures
• The Bunnell “crisscross”
is the classic technique of
end-to-end suture

Kessler grasping
• Adv of modified kessler
• Knot buried
• Single suture used
• Disadv
• Proper approximation difficult

Fish-Mouth End-to-End Suture (Pulvertaft)

End-to-Side Repair
• End-to-side repair frequently is used in tendon transfers when one
motor must activate several tendons

Roll stitch
• The roll stitch is especially
useful for suturing extensor
tendons over or near the
metacarpophalangeal joints.

Tendon to bone
• Pull out technique
• Tendon-to-tendon repair of grafts may be preferable in children to
avoid physeal injury.
• For tendon-to-bone repairs, the core suture techniques used most
often have included the Kessler and a modification of the Bunnell
crisscross suture in which the pull-out wire is looped over a straight
needle that is passed transversely through the tendon
approximately 10 mm from the cut end. This leaves the pull-out
wire attached to a loop of the suture proximally in the tendon to be
passed into the bone distally

Timing of Flexor Tendon Repair
• Primary:<24 hrs
• Delayed primary:<14 days
• Secondary : 14 d-28 d
• Late secondary:>28 days

• Primary repair :can be performed in patients who have a
• clean wound with either a tendon injury or
• a tendon injury combined with a neurovascular bundle injury or
• a fracture if it can be fixed and stabilized satisfactorily.
• If this is impossible, a secondary repair should be considered.
• A secondary repair is indicated if the tendon injury is associated with
complicating factors that could compromise the end result.
• These factors include
• extensive crushing with bony comminution near the level of tendon injury,
• severe neurovascular injury,
• severe joint injury, and
• skin loss requiring a coverage procedure, such as skin grafting or flap coverage

Partial Flexor Tendon Lacerations
• complications
• rupture,
• triggering, and
• tendon entrapment
• loads required to rupture 50% and 75% tendon lacerations were
higher than the physiological loads measured during normal active
motion

• If a tendon is lacerated 60% or more, it is treated the same as a complete
transection.
• A core suture is placed in the tendon, and the surface of the tendon is sutured with
a continuous 6-0 nylon suture. The flexor sheath is repaired when possible.
• Postoperative management of a 60% or greater tendon laceration is the same as
for a complete transection, with immobilization, early controlled passive motion,
and restoration of forceful activities at 10 to 12 weeks.
• If the laceration is less than 60%, the injury is evaluated for the risk of
triggering.
• If triggering is seen, the flap of tendon is smoothly débrided, and the flexor sheath
is repaired to help avoid entrapment or triggering of the flap in the defect in the
flexor sheath.
• Postoperatively, the part is protected with dorsal block splinting for 6 to 8 weeks,
and more forceful activities are resumed gradually after approximately 8 weeks.

• Bruner incision: zigzag incision-it keeps away the scar tissue from
repair site
• Strands: no. of suture filaments actually crossing the repair site
• Two strand-bunnel,Kessler
• Four strand-Strickland
• Six-savage
• 8-silva

• A2 located in prox half of prox phalanx
• A4 at middle 3rd of middle phalanx
• Repair of pulleys
• Primary
• Using extensor retinaculum sheath/palmaris longus tendon graft

Superficialis finger
• When fdp cut in zone 1 with small distal stump
• Prox stump sutured to middle phalanx
• Distal stump to neck of middle phalanx to prevent hyperextension
deformity at dip.

• Zone I extends from just distal to the insertion of the sublimis tendon to
the site of insertion of the profundus tendon.
• Zone II is in the critical area of pulleys (Bunnell's “no man's land”)
between the distal palmar crease and the insertion of the sublimis
tendon.
• Zone III comprises the area of the lumbrical origin between the distal
margin of the transverse carpal ligament and the beginning of the critical
area of pulleys or first anulus.
• Zone IV is the zone covered by the transverse carpal ligament.
• Zone V is the zone proximal to the transverse carpal ligament and
includes the forearm.

Pulleys
• A2 A4 injury:tendon bowstringing and flexion deformity of the
finger can develop, and excursion of the tendon becomes impaired

Zone 1-quadriga effect
• The flexor digitorum profundus tendon can be repaired primarily by
direct suture to its distal stump or by advancement and direct insertion
into the distal phalanx when the distance is 1 cm or less.
• Excessive trimming and advancement of the tendon can result in a finger
that is held in a flexed position compared with other fingers (the finger
“cascade”-allowing the wrist to drop in extension there is passive
tenodesis effect).
• Although the finger may function reasonably well, uneven tension can be
applied to the common muscle belly of the flexor profundus tendons and
can lead to limited flexion of the remaining profundus tendons (the
“quadriga effect” described by Verdan).
• lengthening of the tendon at the wrist should be considered, or, if
excessive shortening has occurred, tendon grafting may be considered.

Use of finger cascade in detecting tendon cut
• FDS cut: break in cascade
• Both ip jts held in some flexion
• FDP cut
• Finger straighter
• Flexion at pip jt

Leddy and Leddy and Packer
• three types of flexor tendon ruptures, depending on the level to
which the tendon has retracted.
• In type 1, the tendon is found retracted into the palm. If it is within 7 to 10
days of the injury, the tendon should be threaded back into the finger and
reattached with a pull-out wire into the distal phalanx.
• In type 2 ruptures, the tendon has retracted to the level of the proximal
interphalangeal joint. At times, despite the passage of a few months, these
tendons can be reattached as well.
• In type 3, the tendon has retracted only to the level of the distal
interphalangeal joint and usually has a bony fragment attached to it. These
also usually can be treated by reattachment.

• Old, untreated injuries to the flexor profundus in zone I can be
treated by
• tendon grafting,
• tenodesis, or
• arthrodesis of the distal joint

Zone 2
• (Bunnell's “no man's land”),
• Primary repairs at this level frequently fail because of adhesions in
the area of the pulleys
• Technical concerns during the repair procedure include the
• management of lacerations of the profundus and sublimis tendons,
• the appropriate orientation of the profundus with the sublimis slips,
• the attachment of the sublimis slips in the thin flat area,
• the management of the flexor sheath, including the annular thickening
(pulleys),
• the postoperative management, and
• the timing and technique for tenolysis

• Care should be taken when the flexor sublimis has been injured in
the area just proximal to the proximal interphalangeal joint and
distally where the orientation of the proximal and distal portions of
the tendon can be misinterpreted and repairs may be incorrectly
done with the sublimis slips malrotated .
• Care also should be taken to deliver the flexor profundus tendon
through the split portion of the flexor sublimis when the profundus
tendon has retracted proximally

• Prox to chiasm cut: repair both
• At same level cut/distal to chiasm-repair only fdp

• 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

Tenolysis
• tenolysis is considered when the patient has
• reached a plateau in postoperative rehabilitation, and
• when all wounds are supple and flexible, and
• the skin is soft with minimal or no induration around the scars.
• Fracture and joint injuries should be healed, and there should be no or minimal
residual joint contractures.
• A near-normal passive range of motion is preferred.
• Normal sensation is preferred; however, if digital nerves have been repaired,
progress toward return of sensation should be observed.
• For these criteria to be met usually requires 5 to 6 months after the
tendon repair.
• Three months is considered to be the earliest time for flexor tenolysis,
assuming no improvement in motion in the previous 1 to 2 months.

Zone 3
• the muscle bellies of the lumbricals and the tendons frequently are
interrupted
• If wound conditions preclude tendon and nerve repair, the ends of
the tendons and nerves are sutured to adjacent fascia to prevent
undue retraction.
• 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 finger flexion).

Zone 4
• for exposure it may be necessary to release partially or completely the
transverse carpal ligament.
• Should complete release be necessary, the wrist should not be placed in flexion
past neutral position, but the fingers should be brought into slightly more
flexion than usual to permit relaxation of the musculotendinous units.
• Flexion of the wrist beyond neutral may permit
• subluxation of the repaired tendons out of their normal bed,
• then bowstring them just under the sutured skin.
• When it is technically possible to accomplish tendon repair and retain part of
the transverse carpal ligament, this problem is eliminated.
• Alternatively, the transverse carpal ligament can be released in a Z-lengthening
configuration, allowing its repair after tendon repair and providing a pulley for
the tendons.

• Space is limited,thus repair fdp index finger and fpl and ring,little and
long fdp combined
• Fds repair only when its not coming in way of others

Zone 5
• The chief difficulty of repair here usually is one of exposure, which
requires a proximal extension and possibly a distal extension of the
typical transverse laceration.

Finger position during injury and its effect
• Flexion :
• Fds fdp cut at diff levels
• Less bunching durind repair
• Less cross union
• Less adhesions
• But diff to find structures
• Extension
• Finding structures easy
• Higher risk of scar and bunching

Delayed repair
• Prolonged delay may permit unacceptable retraction of tendons and
nerves, especially in zones III, IV, and V.
• If it seems that definitive management of the tendons and nerves
may be delayed, an attempt should be made to secure the ends of
the tendons and nerves to the adjacent soft tissues to prevent
retraction before achieving satisfactory wound closure.

Rehabilitation
• Divided into 3 groups acc to protocol used in 1st 3-4 wks
• 1:Immobilization
• 2:early controlled motion
• Duran and houser
• Kleinert and chow
• 3:active mobilization
• Silfverskiold
• strickland

Total immobilization
• Children
• Non compliant adults
• Pt unable to understand the protocol
• C/I fr early mobilization
• Nerve injury repair
• Replantation and vascular repair
• # with unstable repair

• active finger extension is used with passive flexion achieved using a
rubber band attached to the fingernail and at the wrist.
• modified with a roller in the palm to alter the line of force of the
rubber band
• Chow modified kleinert
• Palmar bar
• Elastic band detached at nyt
• Fingers strapped in extension within the splint
• Minimize risk of flexion contracture of fingers

• A dorsal splint holds the wrist in 20 to 30 degrees of flexion and the
metacarpophalangeal joints at 40 to 60 degrees. The interphalangeal
joints are splinted in extension.
• The rubber band is passed beneath a roller or a safety pin in the palm
and is secured to another safety pin at the level of the distal forearm
• The safety pin maintains the finger in flexion of 40 to 60 degrees at the
proximal interphalangeal joint with no tension on the rubber band.
• The rubber band should allow full extension of the proximal
interphalangeal joint against the traction of the rubber band.
• With this form of controlled mobilization, it is believed that the flexor
tendon repair is not stretched, and the movement that is allowed can
enhance healing

• After 3 weeks, the dorsal splint is removed, and a wrist band with a
hook for the rubber band is used for an additional 3 weeks. The
patient actively extends the digit against the resistance of the
rubber band. No passive extension or active flexion is permitted.
• The wrist band splint is discontinued at 6 to 8 weeks, and dynamic
extension splinting is used to prevent contractures of the proximal
interphalangeal joint.
• At 8 to 10 weeks, strengthening exercises are permitted,
• and the patient progresses to using the hand normally at 10 to 12
weeks after the repair.

Duran and houser
• controlled passive motion technique with dorsal blocking of the
fingers

Passive flexion of interphalangeal joints, which is done several times each day for 4 to 5 weeks. Duran
and Houser popularized early passive motion after tendon repair

• Zone I includes the area at the interphalangeal joint and the
insertion of the flexor pollicis longus.
• Zone II includes the fibroosseous sheath extending just distal to the
metacarpal head and the metacarpophalangeal joint.
• Zone III includes the area of the metacarpal beneath the thenar
muscles.
• Zone IV corresponds to the carpal tunnel, and
• zone V corresponds to the distal forearm just proximal to the wrist

Rehab
• Postoperative immobilization includes splinting with the wrist flexed
30 to 45 degrees and the metacarpophalangeal and interphalangeal
joints slightly extended.
• The splint is left intact for about 3 weeks, and
• a removable splint is applied for an additional 3 weeks to protect
the wrist and finger against excessive hyperextension.
• Active flexion is begun at about 3 weeks,
• passive extension and more vigorous activities can begin at 8 to 12
weeks.

Zone 1
• This tendon is unique in that it can be advanced without disturbing
its blood supply because it does not have a vinculum.
• Urbaniak and Goldner preferred tendon advancement instead of
tendon grafting because paratendinous adhesions are not as likely
to form after advancement.
• > 1 cm:lengthening of the tendon by Z-plasty just proximal to the
wrist should be done

Zone 2
• a portion of the pulley can be excised to lessen the possibility of
adherence to the pulley of the site of the tendon suture.
• Advancement of the tendon distally to be sutured to a stump that is
shortened to lie distal to the metacarpophalangeal pulley has the
advantage of moving the repair site from beneath the area of a
pulley

Zone 3
• the proximal end frequently retracts to near the wrist level
• requires an additional incision at the wrist

Secondary Repair and Reconstruction of Flexor
Tendons
• After 1 month, delivery of the flexor tendon through the
fibroosseous sheath and the pulleys is extremely difficult, and
• in those circumstances, in the absence of extensive scarring and
destruction of the tendon sheath, traditional single-stage flexor
tendon grafting can be done.
• two-stage tendon grafting
• extensive disturbance of the flexor sheath and pulleys,
• joint contractures, and
• nerve injury,

2dry repair
• direct suture at the site of division,
• by tendon graft, or
• by tendon transfer

• Before tendons are secondarily repaired, certain requirements must be
met, as follows:
• (1) wound erythema and swelling should be minimal;
• (2) skin coverage must be adequate;
• (3) the tissues through which the tendon is expected to glide must be
relatively free of scar;
• (4) the alignment of bones must be satisfactory, and any fractures must
be healed or fixed securely;
• (5) joints must have a useful range of passive motion; and
• (6) sensation in the involved digit must be undamaged or restored, or it
should be possible to repair damaged nerves directly or with nerve grafts
at the time of tendon repair

Flexor and extensor tendon injury

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