Flexor tendons injuries are complex and require careful management. There are 5 zones of injury along the finger. Pulleys help the tendons glide efficiently. The biological healing is weak initially. Assessment involves identifying the injured flexor digitorum profundus and superficialis tendons. Various repair techniques aim to provide strength for early motion while minimizing bulk and adhesions. Post-operative rehabilitation protocols like Duran and Strickland use controlled motion to promote longitudinal scar formation and intrinsic healing over extrinsic healing.

1. Flexor Tendons
Injuries
By
Mohamed Mohamed Salah Eldeeb

2. Basic Science

3. Blood Supply
V: Vinculum
L: Longus
B: Brevis
P: Profundus
S: Superficialis

4. Pulley System • Pulley system prevents
bowstringing
• Bowstringing increases
the moment arm;
leading to increase in
tendon excursion
needed to make a given
angular motion
• Improve the mechanical
efficiency of the tendon
• Most important A2 and
A4
• A1 site of trigger finger

5. Flexor tendons arrangement in carpal tunnel

6. Injury Zones
Zone I distal to FDS insertion
Zone II FDS and FDP slide in common
sheath
Zone III area of lumbircal origin
Zone IV carpal tunnel
Zone V distal forearm

7. Tendon
healing
Two forms:
• Intrinsic healing: by the activity of fibroblast
derived from the tendon.
• Extrinsic healing: by activity of fibroblast
derived from the epitendon and haematoma
of injury.
• Extrinsic healing results in adhesions
formation and limit the gliding of the tendon
through the sheath.

8. Biological
fact
• Traumatized tendon ends tend to soften
during the first 2 weeks post-surgery, thus
reducing the holding power of the suture.
• The innately weak and slow biological
healing creates a “no gain” lag period in
tendon strength during the first 3 to 4 weeks
after surgery.
• We should ensure that the strength of
surgical repairs is greater than the forces
generated during unresisted active finger
flexion plus a certain safety margin.

9. DIAGNOSIS

10. Assessment: A; FDS, B; FDP

11. Finger Cascade

12. Flexor Tendon
Repair Techniques

13. Incisions
Avoid crossing
perpendicular on the
creases.

14. Tendon
Retrieval
• Avoid trauma to synovial sheath lining
• Forcep/hemostat/skin hook if proximal stump
visible
• Proximal to distal milking, reverse Esmarch
• Suture catheter to proximal tendons in palm
and deliver distally
• Retraction often limited to A1/A2 pulley region
by vinculae If lacerated proximal to vinculae or if
vinculae disrupted, tendon ends may retract
into palm If proximal stumps have retracted into
the palm the correct orientation of FDS and FDP
must be re-established (such that FDP lies volar
to Camper's Chiasm)

15. Camper’s Chiasm

16. Tendon
Advancement
• Previously advocated for zone 1 repairs, as
moving the repair site out of the sheath was
felt to decrease adhesion formation –
• Disadvantages Shortening of flexor system
• Contracture
• Quadregia effect

17. Quadregia effect

18. General
principles for
tendon
repair
• To provide repair strength sufficient to
permit motion in the first 6 weeks
• Good end to end coaptations, no gap
• Adequate tensile strength to resist gapping
during early 6wks
• Frictionless repair, minimal bulk
• Non-traumatizing

19. Items of
tendon
repair
• Suture material
• Core or epitendinous repair, and number of
strands
• Knot out or in
• Locking vs grasping
• Repair of both tendons or only one
• Repair techniques

20. Suture material
• Non-absorbable, braided or monofilament
• Comparison: nylon, a monofilament suture
• Prolene, a monofilament polypropylene suture
• Ethibond, a braided polyester suture
• Stainless steel (braided)
• Fibrewire, a polyethylene-based braided suture with reported
superior strength characteristics.

21. Core or
epitendinous,
crossing
strands
• Core suture is mechanically better
• Epitendinous just to smooth the repair site
with little mechanical advantages
• The tensile strengrth of repair is related to
the number of crossing strands
• Four strands or more should be chosen, two
crossing strands less effiecient
• Suture calibre related to the size of the
tendon

22. Examples of four or more strands

23. Knot in or
out
• The knot being either within or away
from the repair site has not been
shown to have an independent effect
on tensile strength.
• Greater quantity of suture within the
repair site may increase repair site
bulk.
• External knot distant to the repair site
may also adversely affect tendon
gliding within the flexor tendon sheath
by increased friction or knot trapping
between tendon and sheath.

24. Locking vs Grasping loop
• The loop of the core
suture that is
positioned to “lock”
rather than “grasp”
the tendon stumps
shows greater
strength.
• Similarly, increasing
the number of locks
or grasps increases
tensile strength

25. Repair both
flexors or
one
• For better functional results repair of both is the
role.
• If the tendon ends are severely injured, unclean,
or ragged, or if there is insufficient tendon for
repair, excision of the FDS tendon and isolated
repair of the FDP tendon may be the best
alternative.
• Excision of one slip of the FDS tendon may be
necessary to diminish the bulk of the repair and
facilitate gliding through the tendon sheath.
• In cases where only repair of the FDS tendon is
possible, FDP tenodesis to the middle phalanx or
DIP joint fusion may be necessary.

26. Repair techniques
• Tendon to bone.
• In FDP avulsion

27. End to end

28. Post Operative Care

29. Rehabilitation
Goals
• Promote intrinsic tendon healing and
minimize extrinsic healing and adhesion
formation to improve gliding.
• Early post operative tendon mobilization
biologically affect the scar formation at the
repair site.
• The collagen is laid down longitudinally
parellel to axial force.
• Load at failure for mobilized tendon is
twice that for immobilized tendon at two
weeks post-operative.

30. Immobilization
Programme
• Indicated in:
• Children and adults who are difficult or
untrustful to comply with the
mobilization programme.
• Associated injuries or co-morbidities
precluding mobilization programme
compliance.

31. Kleinert splint
• Dorsal splint with wrist in flexion.
• Finger tied by rubber band in
flexion.
• Active extension is done.
• Finger return back in flexion by pull
of the rubber band.

32. Duran protocol
• Controlled passive motion
method.
• A, Dorsal blocking splint is used
to hold wrist in mild flexion, MP
joints in about 45 degrees of
flexion, and PIP and DIP joints in
nearly full extension.
• B, Full isolated passive flexion of
DIP joint.
• C, Full isolated passive flexion of
PIP joint.
• D, Full passive flexion of MP, PIP,
and DIP joints.

33. Strickland protocol
• Controlled place-and-hold motion.
• A, Dorsal blocking splint that positions
the wrist in 20 degrees of palmar
flexion, MP joints in 50 degrees of
flexion, and IP joints in extension.
• B, Splint with a wrist hinge is
fabricated to allow for full wrist
flexion, wrist extension of 30 degrees,
and maintenance of MP joint flexion
of at least 60 degrees.
• C, After passive digital flexion, the
wrist extends and passive flexion is
maintained.
• D, The patient maintains digital flexion
and holds for about 5 seconds.
Patients are instructed to use the
lightest muscle power necessary to
maintain digital flexion.

34. Thank You