This document discusses trigger finger, which is caused by thickening of the flexor tendon that gets caught on the edge of the A1 pulley when flexing the finger. It describes the anatomy of the tendon pulley system in the hand. Trigger finger is most common in the ring finger and is often due to repetitive trauma. Symptoms include inability to smoothly flex or extend the finger and locking of the finger. Treatment involves splinting, NSAIDs, corticosteroid injections, and surgery to release the A1 pulley if conservative measures fail. Pediatric trigger thumb has a different etiology and presentation compared to adults and usually requires surgery for release.

1. Dr. Yeshwanth Nandimandalam
Trigger finger

2. Introduction
 Trigger finger or Stenosing tenosynovitis of finger
is caused by a nodule or thickening of flexor
tendon which catches on the proximal edge of A1
pulley when the finger is actively flexed.

3.  Trigger fingers are characterized by the inability
to flex or extend the digit smoothly.
 All digits can be affected, but the ring finger is
most often involved, followed by the thumb and
the long, index, and small fingers, in that order.
 More than one trigger digit can be present on the
same hand.
 Triggering of digits in both hands is also common

4. Anatomy
 From the metacarpal heads to the distal
phalanges all five digits are provided with a
strong unyielding fibrous sheath in which the
flexor tendons lie .
 Synovial sheath is reinforced by a system of
fibrous pulleys
 It include 5 annular pulleys and 3 cruciform
pulleys

5.  A1, A3, and A5 overlie the MP, PIP and DIP joints
respectively
 A2 and A4 over proximal and middle phalanx
respectively
 A2 and A4 are considered most important. Their
disruption leads to bowstringing, reduced
mechanical efficiency and decreased flexion.

6.  Cruciate pulleys function to prevent sheath
collapse and expansion during digital motion
 They facilitates approximation of annular pulleys
during flexion
 C1 -Near head of proximal phalanx
 C2 - Base of middle phalanx
 C3 - Distal end of middle phalanx

7.  Flexor synovial sheath for
thumb starts proximal to carpal
canal and its retinacular portion
has 2 annular pulleys and an
oblique pulley
 A1 – At MCP joint
 A2 – At IP joint
 Oblique – Middle of proximal
phalanx

8.  Function of this system is to increase the
mechanical efficiency by preventing bowstringing

9. Etiology
 Congenital
 Repetitive trauma such as may occur in gardening,
sewing, cutting with scissors, typing etc
 Associated with conditions like Rheumatoid arthritis,
Gout, Diabetes, Hypothyroidisism, Amyloidosis
 Other rare causes are: -
- Abnormal collateral ligament that may catch on a bony
prominence on the side of metacarpal head.
- Abnormal seasmoid bone on the metacarpal head.
- Interposed capsule due to trauma.

10. Pathophysiology
 The flexor digitorum profundus, flexor digitorum
sublimis, and flexor pollicis longus should glide
through the annular pulley system unobtrusively
in flexion and extension of the digits.
 Normally, there is a double synovial sheath that
facilitates smooth gliding.
 This synovial membrane is intimately involved
with the tendons and the pulley system.

11.  Stenosing tenosynovitis is a pathologic
disproportion between the volume of the
retinacular sheath and its contents
 This disproportion inhibits gliding as the tendon
moves through the A1 pulley
 Inflammation manifests itself as a spindle shaped
thickening in a localized area of the flexor tendon

12.  There are two types of pathologic involvement of
the tendon that occur with clinically triggering
digits— nodular and diffuse.
 In nodular stenosing tenosynovitis, this occurs
just distal to the A1 pulley, where tendon friction
deforms the tendon and causes a nodule to form.
 In diffuse stenosing tenosynovitis, the
inflammation will not be as localized and may well
extend beyond the A1 pulley

13. Signs and symptoms
 Pain at the root of finger
 Swelling
 Tenderness
 Palpable nodule
 Abnormal crepitus
 Locking of the digit either correctable or fixed

14. EAST WOOD CLASSIFICATION
 Grade 0 : mild crepitus in a non triggering digit
 Grade 1 : uneven movement of the digit
 Grade 2 : clicking without locking
 Grade 3 : locking of the digit that is either
actively or
passively correctable
 Grade 4 : locked digit.

15. Medical management
 Nonsteroidal anti-inflammatory drugs should be
the initial form of treatment unless inadvisable
because of the patient’s age or the presence of a
peptic ulcer diathesis.
 Use of NSAIDs can be combined with massage,
ice therapy, splinting, and corticosteroid
injections.

16. Splinting
 Affected finger should be kept in an extended position.
 The splint helps to rest the joint and prevents
from curling of fingers into a fist while sleeping
 Grade 4 (locked) digits will not respond to
splinting
 For the splints to be successful, they may have to be
worn for as long as 4 months
 In early nodular tenosynovitis, the combination of finger
splinting, and NSAIDs has been successful

17. Coticosteroid injection
 All grades of tenosynovitis have been treated with
injections, and all have been reported to respond.
 Nodular trigger digit can be treated with an
injection into the tendon sheath. An NSAID
should accompany the injection if there is no
history of ulcer disease.

18.  Diffuse stenosing tenosynovitis should be treated
with only one steroid injection and only if
symptoms have been present for less than 4
months.
 If symptoms have been present for longer than 4
months or persist after the initial injection, surgical
release is appropriate without further
nonoperative treatment.

19.  Steroid injection into the tendon sheath can be
done from either a lateral or a palmar approach.
 The lateral approach is less painful because the
neurovascular bundle lies palmar to the area of
injection.

20.  From the radial border of the finger, the needle is
inserted into the midlateral area of the proximal
phalanx over the first cruciate pulley.
 The skin and subcutaneous area are
anesthetized with 1% xylocaine without
epinephrine

21.  The needle is inserted only until slight resistance
is felt. The patient is asked to wiggle the finger.
 Slight grating can be felt at the end of the needle.
 If the needle is in the tendon proper, there is
paradoxical motion of the needle and syringe

22.  The rest of the anesthetic is then injected into the
tendon sheath.
 The needle is disconnected from the syringe but
left in place, and the syringe is reloaded with 0.75
mL of corticosteroid and 0.25 mL of 1% xylocaine
which is reconnected to the needle.
 The patient is again asked to wiggle the finger to
ascertain the correct position of the needle. The
injection is given, and the needle is withdrawn

23.  It is preferable to use the midlateral approach for
patients who present with grade 1 or grade 2
disease and a small nodule and for patients with
diffuse tenosynovitis of the fingers.
 The treated digit should remain anesthetized for 3
to 4 hours.
 Benefits from the steroid injection should persist
for 2 to 5 days after the procedure

24.  The palmar approach is equally effective, but it
can be more painful because the palmar aspect
of the hand has more sensory endings than the
lateral and medial aspects of the fingers.
 The palmar approach is preferred for grade 3 or
grade 4 disease and for the second injection.

25. Surgical treatment
 Surgical release of the A1
pulley can be done through
either a transverse or a
longitudinal incision in the
palm.
 Local anesthesia is preferable
because it allows active
flexion and extension on the
operating table, and the
completeness of the release
can be confirmed.

26.  The A1 pulley release is
performed, and the patient is
asked to flex and extend the
digit intraoperatively.
 If triggering is still occurring, the
release should be checked for
completeness; further release of
the A1 pulley may be warranted.
 If no further triggering occurs,
the tourniquet is released,
bleeding is checked, and the
patient is asked to make a fist

27. Percutaneous technique
 After the finger or thumb has been well
anesthetized, the patient is asked to actively
trigger the affected digit.
 A 20-gauge, 1-inch needle is then inserted with
the sharp bevel parallel to the tendon.
 The needle is inserted one third the distance from
the distal palmar crease to the base of the long,
ring, or small finger.

28.  In the case of the index
finger, the needle is inserted
one third the distance from
the distal thenar crease and
the base of the finger.
 These locations have been
found to consistently
correlate with the middle of
the A1 pulley and to allow
cutting both proximally and
distally to completely
transect it24

29.  In the thumb, the needle is inserted at the
intersection of the proximal thumb crease and a
line perpendicular to it. Insertion at this point
avoids the radial digital nerve of the thumb.
 The A1 pulley is cut with a swiping movement of
the needle. A definite grating should be felt.

30.  Bevel of the needle should be
oriented longitudinal with the
needle
 Once the pulley is thought to have
been transected, the needle is
withdrawn, and the patient is asked
to flex the digit.
 If triggering persists, the nodule is
gently palpated to feel where it is
catching on the A1 pulley. The
needle is then reinserted so as to
cut more proximally or distally

31.  Drawbacks of percutaneous release include
-incomplete release of the A1 pulley and
-potential injury to adjacent neurovascular
structures, to the tendons themselves, or to the
volar plate.
 The proximity of the radial sensory nerve to the
A1 pulleys of the thumb and the index finger has
prompted that these digits not be treated with
percutaneous release.

32. Complications
 Injection of steroid into the neurovascular bundle
can cause permanent damage of the digital nerve
or artery
 Complications of surgical release include
-digital nerve transection,
-A2 pulley injury with subsequent bowstringing of
the tendons,
- bothersome scars,
- recurrent symptoms,
- stiffness, and
- sympathetic dystrophy.

33.  Complications of percutaneous release include
-incomplete release of the A1 pulley and
-potential injury to adjacent neurovascular
structures and to tendons themselves.

34. Paediatric Trigger thumb
 Pediatric trigger thumb and trigger finger
represent distinct clinical entities and should not
be managed like their adult counterparts.
 Trigger thumb is 10 times more common than
trigger finger among infants and children.
 Approximately 25% of patients with trigger thumb
experience bilateral involvement.

35. Etiology
 The etiology of acquired pediatric trigger thumb
remains unknown.
 It is postulated that constant flexed position of the
thumb during the prenatal and neonatal periods
results in collagen degeneration and synovial
proliferation, which produces a FPL nodule and
thickening of the tendon sheath.
 This nodule was first recognized by Alphonse
Henri Notta in 1850 and is now commonly
referred to as a Notta nodule

36.  Pediatric triggering secondary to intratendinous
calcification, granulation tissue, and cysts also
has been reported.
 In addition, pediatric trigger finger has been
linked with mucopolysaccharide storage disorders
such as Hurler syndrome and Hunter syndrome

37. Clinical features
 Patients most commonly present at
approximately 2 years of age.
 Parents may give a history of
triggering of finger assosciated with
a palpable nodule
 In most patients, a fixed flexion
deformity of the IP joint, rather than
triggering is noted.

38. Management
 Nonsurgical management of pediatric trigger
thumb includes passive extension exercises and
splinting.
 The splints were applied continuously for 6 to 12
weeks before transition to night time splinting
 Currently, the role of nonsurgical management
remains unclear with the late presentation of
patients with fixed contractures.

39. Surgical management
 Trigger thumb release is typically performed
under general anesthesia.
 A 1-cm transverse incision is created at the
thumb palmodigital (MCP flexion) crease

40.  The flexor tendon sheath is then exposed with
blunt dissection
 The A1 pulley is sharply incised under direct
visualization
 The proximal edge of the oblique pulley should be
identified and preserved to confirm complete
division of the A1 pulley and to prevent
inadvertent bowstringing and loss of motion

41.  Upon inspection of the unroofed
FPL, the Notta nodule is easily
identified but does not require
excision
 The IP joint is hyperextended to
stretch the contracted volar plate
 The Notta nodule should be
visualized during passive IP joint
extension to ensure that the FPL
glides distally without further
entrapment or triggering

42.  In trigger fingers, in addition to A1 pulley release,
additional measures such as resection of one or
both slips of the FDS tendon are done.
 An extensile Brunner-type incision is created over
the A1 pulley

43.  After division of the A1 pulley, flexor tendon
gliding is evaluated with passive digital range of
motion.
 Proximal decussation of the FDS is a common
source of triggering and should be checked for

44.  Single slip or multiple slips of the flexor digitorum
superficialis tendon should be resected and
checked for finger movement.
 Once an adequate release is achieved, skin
closure is completed and a bulky soft dressing is
applied

45. Have a good day