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acute flexor tendon injury
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Acute Flexor Tendon Acute Flexor Tendon Injuries(Zone I)Injuries(Zone I)
Ashraf Abdelaziz Lecturer of orthopedic surgery
Alzhraa University HospitalAl-Azhar university
Egypt 2014
ObjectivesObjectives
Anatomy
Examination
Preoperative Considerations
Repair of Zone 1 Lacerations
Postoperative Rehabilitation of Zone 1
Complications
Critical points
AnatomyAnatomy
The FDS muscle has two heads of origin.
The ulnar head arises from the anterior aspect of the
medial epicondyle, the ulnar collateral ligament of the
elbow, the medial aspect of the coronoid process, andelbow, the medial aspect of the coronoid process, and
the proximal ulna.
The radial head arises from the proximal radius
immediately distal to the insertion of the supinator
muscle and lies deep to the pronator teres.
The median nerve is loosely adherent to the deep
surface of the FDS muscle.
At the mid-forearm, the FDS divides and sends tendons
to the middle and ring fingers (superficial) and the index
and small fingers (deep).
The innervation of the FDS is from the median nerve.
The FDP muscle belly arises from the volar aspects of
the proximal three fourths of the ulna and the
interosseous membrane.
In the deepest layer of the volar forearm, the FDP
muscle lies adjacent to FPL.muscle lies adjacent to FPL.
The ulnar nerve innervates the ulnar half
The anterior interosseous branch innervates the radial
half.
FPL tendon arises from the volar aspect of the middle
third of the radial shaft and from the lateral aspect of
the interosseous membrane.
The anterior interosseous nerve innervates the FPL.
Five anatomic zones.
Zone 5 extends from the muscle-tendon junction to the
proximal crease of the wrist,
Zone 4 within the carpal tunnel.
Zone 3 Distal to the transverse carpal ligament to distal
crease.crease.
The proximal aspect of the A1 pulley is the entrance to
zone 2, or “no man's land.”
Zone 1 is distal to the insertion of the FDS tendon.
The FDS tendon enters the A1 pulley and divides into
two equal halves that rotate around the FDP tendon.
Then insert as two separate slips on the volar aspect of
the middle phalanx.
The pulley mechanism consists of:
The annular pulleys are keep the tendon closely to the
underlying bone.
Annular pulleys
Cruciform pulleys.
underlying bone.
Their function allow an amount of tendon excursion to
improving the efficiency of the flexor apparatus
Structural analysis of these pulleys has suggested that each
of the three layers of the pulley has a strategic purpose.
I. The innermost layer secretes hyaluronic acid and is
designed to facilitate gliding.
II. The middle layer, rich in collagen, resists palmar
translation of the tendons.translation of the tendons.
III. The outer areolar layer facilitates nutrition of the pulley.
The A1, A3, and A5 pulleys take origin from the palmar
plates of the MP, PIP, and DIP joints.
The A2 pulley originates from the proximal phalanx,
The A4 pulley originates from the middle phalanx.
The dual nutritional supply of the digital flexor tendons
in zone 2 is from vascular perfusion and synovial
diffusion
The paratenon allows for passive nutrient delivery to
the flexor tendon within the flexor sheath by means ofthe flexor tendon within the flexor sheath by means of
diffusion.
The flexor tendons receive direct arterial supply from
the well-developed vincular system, osseous bony
insertions.
ExaminationExamination
The skin on the volar and dorsal aspects of the
injured digit is examined.
The presence of additional injuries.The presence of additional injuries.
Deformity of the digit signifies either a fracture
or a ligamentous injury.
The evaluation of digital neurovascular injury.
The tendons should be examined
individually in each finger.
FDS tendon examination.
FDP tendon examination.
Examination of digital nerves.
Capillary refill of the volar digital pulp and the
nail bed is assessed.
X rays:AP
LTLT
Oblique
Preoperative ConsiderationsPreoperative Considerations
Optimal timing of flexor tendon repair depends on the
history and physical examination.
Injury to both arteries, urgent exploration.
Early repair, the wound is easier to manage, and the tendon
ends are fresh for the repair.
In delayed cases adequate consideration should be given to
the possible need for tendon reconstruction, and may
require the use of a primary tendon graft or placement of
a tendon spacer.a tendon spacer.
Repair of both tendons is preferable,
however, for optimal gliding, In select cases, excision of
one slip of the FDS tendon may be necessary.
If the tendon ends are severely injured, excision of FDS and
repair of the FDP may be the best.
Isolated repair of the FDP tendon creates a simpler finger
and diminished adhesion formation in a severely traumatized
digit.
In cases when only the FDS not injuried, FDP tenodesis to In cases when only the FDS not injuried, FDP tenodesis to
the middle phalanx or DIP joint fusion may be necessary.
Repair of Zone 1 Lacerations or AvulsionsRepair of Zone 1 Lacerations or Avulsions
If the distal tendon stump is < 1 cm long, FDP primary
tendon to bone fixation.
If >1 cm of FDP stump is available, primary tenoraphy is
done.done.
Tendon to Bone RepairTendon to Bone Repair
The tourniquet is placed on the arm.
The limb is exsanguinated.
An extensile mid-lateral or zigzag incision is used to
expose the flexor apparatus.expose the flexor apparatus.
The bone at the volar base of the distal phalanx is exposed
to establish a repair footprint for the tendon reinsertion.
Pull-out suture methods and internal suture(anchor)
methods.
A) Traditional pull-out suture.
Placement of the corner sutures is useful to reinforce
the repair site.
The pull-out sutures (3-0 Prolene) are passed through
the distal phalanges and are tied over a button placedthe distal phalanges and are tied over a button placed
on the nail plate dorsally.
This “pull-out” suture usually is removed after 6 weeks.
B) The internal suture methods use suture
anchors.
Whatever technique is used, it is essential
that the FDP stump be secured directly to
the footprint in the distal phalanx when
the knot is secured.
Leddy 1977 classified FDP avulsions into three
types.
In type I avulsions, the FDP tendon retracts into
the palm, These injuries are best treated by urgent
surgical repair.surgical repair.
Type II avulsions, the tendon stump retracts to the
level of the PIP joint,
A large bone fragment is attached to the stump of
the FDP tendon in type III injuries.
This fragment usually prevents tendon
retraction proximal to the distal edge of
the A4 pulley.
Fracture repair using K. wire or screw
fixation is necessary for treatment of this
injury.
In some cases with a small fracture
fragment, the bone may be excised, and
the tendon may be advanced and suturedthe tendon may be advanced and sutured
into the distal phalanx.
It is preferable to have the needles exit
the nail plate beyond the lunula to avoid
nail deformity.
The button and suture is left in place forThe button and suture is left in place for
6 weeks.
Postoperative Rehabilitation of Zone 1Postoperative Rehabilitation of Zone 1
The method of rehabilitation is
significantly influenced by the compliance
of the patient, the nature of the wound,of the patient, the nature of the wound,
and the method of the repair.
A postoperative program controls the amount of
force to the repair site,
Improvements in tendon excursion.
Excessive force during rehabilitation can lead to
tendon gapping or rupture.tendon gapping or rupture.
Many factors influence the aftercare
regimen, including patient compliance,
edema, suture size and configuration,
wound complications, tight wound
dressings, systemic conditions, ordressings, systemic conditions, or
concomitant injury.
Therapy typically begins 1 to 5 days after
surgery.
The MP joints are positioned at 70
degrees of flexion, a position that
promotes gentle stretch on the collateral
ligaments of the MP joints and prevents
excessive stretch on the flexor tendons.
ComplicationsComplications
Infection,
Skin flap necrosis,
Tendon repair rupture,Tendon repair rupture,
Tendon adherence.
A prerequisite for successful tenolysis is that
full or nearly full passive digital flexion has
been achieved.
Tenolysis is a surgical strategy that should be
considered 4 months after tendon repair.
Interphalangeal joint contracture can occur
after flexor tendon repair,
These contractures can be resolved using
passive stretching exercises and static
progressive splints as needed.
CRITICAL POINTS: ZONE 1 REPAIR CRITICAL POINTS: ZONE 1 REPAIR
All flexor tendon avulsion injuries are best treated
early,
Direct tendon repair is preferable if there is > 1 cm of
distal stump.
Tendon repair to bone is done if there is <1 cm of distal
tendon stump.
Either suture anchors or pull-out suture .
A tendon that is inserted too tight leads
to quadrigia.
Two-strand repair techniques may be
insufficient for rehabilitation programs
that employ early active range of motion.
Technical Points
prepare the bony insertion site.
Ensure the tendon is seated in the Ensure the tendon is seated in the
footprint.
Place additional peripheral sutures that
secure the tendon.
Postoperative Care
Apply dorsal splint with wrist and MP
joints flexed and PIP and DIP joints at 0
to 10 degrees.
Use a graded rehabilitation protocol
under supervision of a qualified therapist.
Thank youThank you