This document discusses flexor tendon injuries. It covers anatomy of the flexor tendons and pulley system. It describes zones of injury, techniques for repair, and post-operative rehabilitation. For zone 2 injuries or when primary repair is not possible, options include tenolysis to release adhesions, tendon transfers, or single-stage tendon grafting using a smaller caliber graft passed through the pulley system. The goals are to perform a strong repair, minimize adhesions, and allow early controlled motion to promote healing.

1. Flexor Tendon Injuries
Dr Sanjibani Sudha

2. FLEXOR TENDON INJURIES
• Anatomy
• Nutrition
• Healing
• Diagnosis
• Techniques
• Zone I
• Zone II injuries
• Partial lacerations
• Post op rehab
• Reconstruction ladder

3.  There are 12 flexor tendons in the hand and forearm
regions, they include finger, thumb flexor and wrist
flexor.
 Finger flexor are FDS,FDP
 Thumb flexor FPL
 Wrist flexor FCR,FCU,PL

4. Anatomy
• Extrinsic flexors
– Superficial group
• PT, FCR, FCU, PL
• Arise from medial
epicondyle, MCL,
coronoid process

5. Anatomy
• Extrinsic Flexors
– Intermediate group
• FDS
• Arises from medial
epicondyle, UCL,
coronoid process
• Usually have independent
musculotendinous origins
and act independantly

6. Anatomy
• Extrinsic flexors
– Deep group
• FPL – originates from
entire medial third of
volar radius
• FDP – originates on
proximal two thirds of the
ulna, often has common
musculotendinous origins

7. Anatomy
• Carpal
tunnel
– 9 tendons
– Median
nerve

8. Anatomy
• Flexor sheaths
From distal palm(neck of
metacarple) to middle
of distal phalynx

9. DIGITAL FLEXOR SHEATH
• Consist of SYNOVIAL SHEATH and PULLEYS(inter
woven condensed fibrous bands
• SYNOVIAL sheath is thin layer of continous smooth
paratenon, covering the inner surface of fibrous sheath.
• Provide smooth surface for tendon gliding
• Provide nutrition to tendon
• PULLEY SYSTEM is unique consists of annular pulley
and cruciate pulleys

10. • Cruciate pulleys are compressible , allowes
digital flexion to occur with condensation of fibro
osseous sheaths at inner part of flexed finger.
called as CONCERTINA effect

12. pulleys
• 5 annular pulleys and 3 cruciate pulleys
• Annular pulleys are heavier,condensed and rigid
• A1 A3 A5 originates from palmar plate of MCP PIP DIP
joints. A2 A4 from proximal and middle phalynx
• A2 is the broadest one,and encompasses the bifurcation
of fds
• Maintain the anatomical path of tendons clse to bone
and joints, optimising the mechanical efficiency of digital
flexion

14. • Thumb has 3 pulleys ;A1, oblique and A2
• A1 and oblique are fuctionaly imp
• A1 pulley located palmar to MCP jnt,
• Oblique pulley over proximal phalynx .
• A2 near the site of incertion of FPL

15. Anatomy
• Camper’s Chiasma

16. • FDS lies superficial to FDP upto bifurcation of
FDS at the level of MCP J. Then FDS tendon
becomes 2 slips coursing laterally and then
deeper to the FDP tendons .This FDS
bifurcation is in the A2 pulleys area . this part of
FDS also serves to constrain the FDS tendon.
• Deep to FDP tendon the FDS slips rejoin to form
CAMPERS chiasm and distally inserted to
proximal and middle part of middle phalynx

17. Tendon Morphology
• 70% collagen (Type I)
• Extracellular components
– Elastin
– Mucopolysaccharides (enhance water-binding
capability)
• Endotenon – around collagen bundles
• Epitenon – covers surface of tendon
• Paratenon – visceral/parietal adventitia
surrounding tendons in hand
• Synovial like fluid environment

18. Tendon Nutrition
1. Synovial fluid
:produced within tenosynovial
sheath
2. Blood supply
provide by vincular circulation
Vascular supply to flexor
tendon

19. Tendon Nutrition
• Vascular
– Longitudinal vessels
• Enter in palm
• Enter at proximal synovial fold
– Segmental branches from digital arteries
• Long and short vinculae
– Vessels at osseous insertions
• Synovial fluid diffusion
– Imbibition (pumping mechanism)

21. Tendon Nutrition
• Dorsal vascularity
• Avascular zones
– FDS (over proximal
phalanx
– FDP (over middle phalanx)
• Nutrition vital for rapid
healing, minimization of
adhesion and restoration
of gliding

22.  Nutrition of tendon
 Suspensory ligament of tendon
 Stabilization of tendon

23. FDP has 2 vincula; a fan like short vinculum and
a cord like long vinculum.
Short v is located at insertion of FDP tendon
Long v connects the FDP tendon through the short
v of FDS tendon on the floor of palmar surface of
phalynx

24. Flexor tendon healing
• 2 forms:
– Intrinsic healing:
– From prolifaration of tenocytes and extracellular
matrix from intrinsic cells. occurs without direct
blood flow to the tendon
– Intrinsic healing is innately weaker then extrinsic
healing
– If intrinsic capacity is disabled such as in
excessive trauma, or in case of post surgical
immobilisation extrinsic healing is favoured

25. • Extrinsic healing: occurs by proliferation of
fibroblasts from the peripheral epitendon;
adhesions occur because of extrinsic healing of
the tendon and limit tendon gliding within fibrous
synovial sheaths

26. Phases of Intrinsic healing
1.Inflammatory (0-5 days) : strength of the
repair is reliant on the strength of the
suture itself
2.Fibroblastic (5-28 days) : or so-called
collagen-producing phase
3.Remodelling (>28 days)

27. Tendon Adhesion
• Increased adhesion formation with:
– Traumatic/surgical injury
• Crush injuries
– Ischemia
• Disruption of vinculae
– Immobilization
– Gapping at repair site
– Excision/injury to flexor sheath components
• Debate over benefit of sheath repair

28. Tendon Adhesion
• Experimental attempts to minimize
adhesion formation
– Oral: steroids, antihistamines, NSAIDS
– Topical: beta-aminoproprionitrile,
hydrocyprolins, hyaluronic acid, collagen
solutions, fibrin
– Physical: silicone/cellophane wrapping,
polyethylene tubes, interposed sheath flaps
• Varying lab success but none proven
definitively or adopted into clinical practice

29. Diagnosis
• History

30. Diagnosis
• Physical exam
• Abnormal resting posture
• Absent FDP / FDS function
• Associated digital nerve and digital vessel
injury
• Discuss nature of injury and postoperative
course with patient

31. I Distal to
sublimis
II No man’s
land
III
Lumbrical
origin
IV carpal
tunnel
V proximal
to carpal tunnel
“No
Man’s
Land”
Bunnell

32. ZONES
• ZONE 1- distal to the insertion of
superficialis
• ZONE 2- no mans land b/w the distal
palmar crease and insertion of the
sublimis
• ZONE 3- lumbrical region b/w distal
palmar crease and the distal end of
transverse carpal ligament
• ZONE 4- zone covered by the flexor
retinaculum
• ZONE 5- proximal to the flexor

33. Zones of Injury
FDS Insertion
Flexor Sheath
(proximal)
TCL
(distal edge) Carpal Tunnel

34. RULES OF REPAIR
• All flexor tendons when severed should be repaired
irrespective of whatever is the zone.
• Ideally fix the fracture and repair the tendon and digital
primarily.
• When delayed repair is done may need a tendon graft
• Flexor tendon sheath should be repaired over the
tendon
• A2 and A4 pulleys of the flexor sheaths should be
preserved to prevent bowstringing and flexon
deformity

35. Timing of surgery
• primary –within 24 hrs
• Delayed primary -1 to 10 days
• Secondary – upto 4 wks
• Late secondary beyond 4 wks
• If wound is clean, primary repair, along
with care of neurovascular injury and
fracture.

36. Incisions
• Factors
– Avoid crossing joints
at 90 deg.
– Preference
– Existing lacerations
– Need to expose other
structures

37. Repair Techniques
• Ideal
– Gap resistant
– Strong enough to tolerate forces generated by
early controlled active motion protocols
• 10-50% decrease in repair strength from day 5-21
post repair in immobilized tendons
• This is effect is minimized (possibly eliminated)
through application of early motion stress
– Uncomplicated
– Minimal bulk
– Minimal interference with tendon vascularity

38. • Core sutures
• Epitenon sutures – reduce bulk and increase strength
• Core sutures –
- careful handling and alignment of tendons
- more dorsal suture placement  better outcome
- More sutures crossing the interaction site, more
strength
- lacerations involving more than 60 % cross-section of
the tendon should be repaired
- 4-0 braided sutures like capromid, polyester
Suture Configurations

39. Core Sutures
• Current literature supports several conclusions
regarding core sutures
– Strength proportional to number of strands
– Locking loops increase strength but may collapse and
lead to gapping
– Knots should be outside repair site
– Increased suture callibre = increases strength
– Braided 3-0 or 4-0 probably best suture material
– Dorsally placed suture stronger and biomechanically
advantageous
– Equal tension across all strands

40. Bunnel Stitch
Kessler Stitch

41. Masson-Allen Criss-cross
Modified kessler Tajima

42. Masson-Allen Criss-cross
Modified kessler Tajima

43. Sheath Repair
• Advantages
– Barrier to extrinsic adhesion formation
– More rapid return of synovial nutrition
• Disadvantages
– Technically difficult
– Increased foreign material at repair site
– May narrow sheathand restrict glide
• Presently, no clear cut advantage to
sheath repair has been established

44. Partial Lacerations
• Controversy in past as partial lacerations
were felt to predispose to entrapment,
triggering and rupture
• Repair if > 50%
• Some advocate repair of partial
lacerations > 60%

45. ZONE 1
• Repair primarily
• To distal stump or advance 1 cm
• More than 1 cm quadriga effect.
• Type 1: 7-10 days retracted in the palm. Repair
with a pull out wire technique.
• Type 2: few months retracted till PIP
• Type 3: retracted upto DIP.
• Old cases: tendon grafting, arthrodesis,
tenodesis

46. 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
• Little excursion distally, therefore adhesions near
insertion less of an issue

47. Pull out wire technique

48. ZONE 2
• Called bunnells zone or no mans land
zone.
• Notorious for bad results, adhesions are a
big problem. Area of pulleys
• Repair both tendons at the same time
• Tendons are sutured malrotated
• Suturing should be intratendonous
configuration.

49. ZONE 3
• Lumbrical zone
• Primarily sutured
• Do not suture the belly of the lumbricals as
it increases the tension of the muscles
• Lumbrical plus syndrome- paradoxical
extension on attempted flexion

50. Tendon Excursion

51. Summary
• Strong gap resistant repair
• 4 strand, locking epitendinous (or
equivalent), 3-0 suture needed for early
active motion
– 4-0 suture, modified Kessler, running
epitendinous suture adequate for more
conservative protocols
• No sheath repair
• Large grasping/locking loops

52. FDP Avulsions
• Commonly male athletes
• Forced extension at DIP during maximal
flexion (jersey finger)
• Often missed due to normal xray and
intact flexion at MP and PIP
– Opportunity for FDP reinsertion lost if
treatment delayed

53. FDP Avulsions
Leddy
and
Packer

54. FDP Avulsions
- Type 1: zig-zag exposure
- Tendon delivered
through pulley system
with catheter passed
retrograde
- Fixed to base of phalanx
with monofilament
suture through distal
phalanx and nail plate
and tied over button
- Fix within 7-10 days
before tendon
degeneration and
myostatic shortening
occurs

55. FDP Avulsions
- Type 2: small bony
fragment retracts to
A3 level
- Can fix up to 6 wks
post injury (less
shortening)
- May convert to type 1
if tendon slips through
A3 pulley and into
palm
- Use same technique
as for type 1

56. FDP Avulsions
- Type 3: large bony
fragment retracts to
A4 level
- Bony reduction and
fixation of fragment

57. Children
• Usually not able to reliably participate in
rehabilitation programs
• No benefit to early mobilization in patients
under 16 years
• Immobilization > 4 wks may lead to poorer
outcomes

58. Reconstruction

59. Ladder of tendon reconstruction
• Tenolysis
• Tendon transfer
• Primary tendon graft
• Two stage tendon graft

60. Tenolysis
• Indication
tendon adhesion
• Preop evaluation
discripency exists between passive and active
range of motion after hand therapy has platued
• Timing
– 3-6 mos. Post repair (minimum)
– Plateau with physiotherapy
• Anesthesia
– Local with sedation
• Allows patient participation

61. Tenolysis
• Technique
– Zig zag incisions
– Adhesions divided maintaining non-limiting
adhesions
– Pulleys reconstructed as needed
• If extensive or not possible convert to staged
reconstruction
– On post op- active range of motion should
begin immediately

62. Single Stage Tendon Grafting
Zone 2
Indications
 injuries resulting in segmental tendon loss.
 Delay in repair that obviates primary repair, such as
laceration that have been neglacted for 3 to 6 weeks and
show tendon degenerations
 Zone 2 injury where large section of tendon have been
damaged and surgeon belives delayed grafting is better
option
 Delay presentation of FDP avulsion injury associated
with significant tendon retraction
Supple joints with adequate passive ROM

63. Principles include
• Place only one graft in each finger
• Never sacrifice intact FDS
• Use a graft of smaller caliber
• Perform the junctions outside the tndon sheath
• Ensure adequate graft tension

64. • Before sx wound should be well healed with no extensive
scarring
• Joint should be free of contracture and maximum
passive range of motion shd have been attained
• Circulation is satisfactory
• At least one digital nerve in affected digit is intact
• Pts with joint contacture shd undergo hand therapy
regimen to achive maximum possible passive range of
motion
• In case of extensive scarring,pulley incompitance,joint
contacture single stage grafting is contraindicated.

65. Single Stage Tendon Grafting
Zone 2
• Technique
– 1 cm distal FDP stump left intact
– 1 cm of FDS insertion left intact (decreased
adhesion formation vs granulating insertion
site)
– Tenodesis of FDS tail to flexor sheath (10-20
deg of flexion) optional
• Hyperextension at PIP in absence of FDS tendon
occurs occasionally

66. Single Stage Tendon Grafting
Zone 2
• Technique
– Graft donors
• Palmaris longus
• Plantaris
• Long toe extensors
• (EIP)
• (EDM)

67. Single Stage Tendon Grafting
Zone 2
• Technique
– Graft passed through pulley system
• Atraumatic technique
– Distal fixation with tension set proximally or
proximal fixation first
– Multiple methods for fixation of graft ends

68. DISTAL JUNCTURE
• No gliding motion occures at distal juncture,making it as
paramount concern there shd be a durable and firm
union between the tendon and FDPstump or volar base
of distal phalynx
• If enough FDP stump is available graft can be sutured to
stump or woven through the stump
• If sufficient stump is not available BUNNEL TENDON TO
BONE PULL OUT technique is used
• Place a transverse drill hole across the base of distal
phalynx and the graft is threaded through the hole and
sutured to itself.in this case graft must be thin enough to
pass through bony tunnel

69. Single Stage Tendon Grafting
Zone 2
• Technique
– Distal
juncture

70. PROXIMAL JUNCTURE
• Is made into FDP tendon just distal to lumbrical origin
• Motor tendon is slit at its end and graft is threaded into
the slit
• pts graft length is estimated in an anesthetized pts by
relaxed position of finger with the wrist in neutral position
• Here each finger shd fall into semiflexion, slightly less
flexed then its ulnar neighbour.

71. Single Stage Tendon Grafting
Zone 2
• Technique
– proximal
juncture
Pulvertaft weave creates a
stronger repair vs end to end
techniques, and allows for
greater ease when setting
tension

72. Post op care
 Early motion exercise have been used
 Protected passive range of motion can be instituted after
2 to 3 days of sx if the juncture are strong enough to
withstand the tesile strength
 Post op splint- static dorsal bloking splint with wrist
positioned in neutral,MP in 45 degree flexion, Ipin
neutral. And worn for 6 weeks after sx


73. Secondary Reconstruction
Zone 1
• Zone 1 (functioning FDS)
– Eg. Late presentation of FDP avulsion
– DIP fusion
– Tendon graft
• Risks damaging FDS function through
injury/adhesions in a very functional finger
• ? Young patients, supple joints, need for active
DIP flexion

74. Secondary Reconstruction
Zones 3, 4 and 5
• Usually associated with 3 – 5 cm gap
– Interposition graft
– FDS to FDP transfer
– End to side profundus juncture

75. Two Stage Reconstruction
• Primary grafting likely to give poor result,
but salvage of functioning finger still
desirable
• Sub-optimal conditions
– Extensive soft tissue scarring
• Crush injuries
• Associated fractures, nerve injuries
– Loss of significant portion of pulley system

76. Two Stage Reconstruction
• Patient selection
– Motivated
– Absence of neurovascular injury
– Good passive joint motion
• Balance benefits of two additional
procedures in an already traumatized digit
with amputation/arthrodesis

77. Two Stage Reconstruction
• Stage 1
– Excision of tendon remnants
• Distal 1 cm of FDP left intact, remainder excised to
lumbrical level
• FDS tail preserved for potential pulley
reconstruction
– Incision proximal to wrist
• FDS removed/excised
• Hunter rod then placed through pulley system and
fixed distally (suture or plate and screw –
depending on implant)

78. Tenolysis
– Release of nongliding adhesions for salvage
in poorly functioning digits with previous
tendon injury
– Avoid in marginal digits
• May not tolerate additional vascular/neurologic
injury
– May need concomitant collateral ligament
release, capsulotomy
– Prepare patient for possible staged
reconstruction

79. Two Stage Reconstruction
• Stage 1
– Rod extends proximally to distal forearm in
plane between FDS and FDP
– Test glide
– Reconstruct pulleys as needed if implant
bowstrings

80. Two Stage Reconstruction
• Stage 1
– Postop
• Start passive motion at 7 days
• Continue x 3mos to allow pseodosheath to form
around implant
• Before stage 2 joints should be supple, and
wounds soft

81. Two Stage Reconstruction
• Stage 2 – implant removal and tendon
graft insertion
– Distal and proximal incisions opened
– Implant located proximally and motor selected
(FDP middle/ring/small, FDP index)
– Graft harvested, sutured to proximal implant
and delivered distally
• Fixed to distal phalanx with pull out wire over
button

82. Two Stage Reconstruction
• Stage 2 – implant removal and tendon
graft insertion
– Proximally sutured to motor with pulvertaft
weave
• FDS transfer from adjacent digit described
• Obviates need for graft
• Difficulty with length/tension
• Postop
• Early controlled motion x 3 wks, then slow
progression to active motion

83. Pulley Reconstruction
• Pulley loss
– Bowstringing = tendon taking shortest
distance between remaining pulleys
– Biomechanical disadvantage
• Excursion translates into less joint motion
– Adhesions/rupture at remaining pulleys due to
increased stress
– A2 and A4 needed (minimum)
• Most biomechanically important
• Some authors advocate reconstructing a 3 or 4
pulley system for optimal results

84. Pulley Reconstruction
• Most done in conjunction with a two stage
tendon reconstruction
• Can be done with single stage tendon
graft
• generally if extensive pulley reconstruction
is required it is better to do a two stage
procedure

85. Pulley Reconstruction
• Methods
– Superficialis tendon
• Insertion left intact
• Remnant sutured to original pulley rim, to
periosteum, or to bone through drill holes
– Tendon graft
• Sutured as above
• Passed through hole drilled in phalanx (risk of
fracture)
• Wrapped around phalanx (requires 6-8 cm of graft)

86. Pulley Reconstruction

87. Pulley Reconstruction
• Methods
– Extensor retinaculum
• Excellent gliding surface
• Difficult to harvest the 8-6 cm required for fixation
around phalanx
– Artificial materials
• Dacron, PTFE, nylon silicone
• Due to abundant atogenous material and
disadvantages of artificial materials, this has not
become common clinical practice
• May be stronger in long term vs autogenous