Acute flexor tendon injuries z 1

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