This document discusses flexor tendon injuries and repairs. It covers tendon anatomy, nutrition, healing, and techniques for both acute and chronic flexor tendon injuries. For acute repairs, it recommends a strong core suture technique with epitendinous sutures and no sheath repair. It also discusses options for chronic injuries like tendon grafting, reconstruction with tendon transfers, and the two-stage reconstruction technique using an implant. Flexor tendon injuries remain challenging to treat due to the complexity of the anatomy and need to balance strength of repair with minimizing adhesions.

1. Flexor Tendon Injuries

2. Flexor Tendon Injuries
• Restoration of satisfactory digital function
after flexor tendon lacerations remains
one of the most challenging problems in
hand surgery
• Prior to the 1960’s tendons lacerated in
“no man’s land” were not repaired in favor
of delayed grafting

3. 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

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
• approx distal palmar
crease
– Predictable annular
pulley arrangement
• Protective housing
• Gliding surface
• Biomechanical
advantage
• Synovial layers
merge at MP
level
• Flexor tendons
weakly attached to
sheath by vinculae

9. Anatomy
• Camper’s Chiasma

10. 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)

11. 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

12. Tendon Healing
• Inflammatory phase (0-5 d); fibroblastic
phase (5d – 6wks); remodelling (6wks-
9mos)
• Intrinsic vs extrinsic healing
• Balance between the two determines
amount of extrinsic adhesion vs intrinsic
tendon healing

13. Tendon Healing
• Factors affecting tendon healing, and
adhesion formation
– Surgical technique
• decreased vascularity
• gapping
– Postoperative motion (passive, active)

14. 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

15. 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

16. Diagnosis
• History

17. Diagnosis
• History

18. 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

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

20. Flexor Tendon Repair
Timing
• Delayed equal or better than emergent
repair
– Acute or subacute acceptable
– Tendon deterioration/shortening after several
wks
– Delay several days if wound infected

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

22. 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

23. 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

24. 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

25. 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%

26. 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

27. Tendon Excursion

28. 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

29. 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

30. FDP Avulsions
Leddy
and
Packer

31. 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

32. 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

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

34. 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

35. Reconstruction

36. Single Stage Tendon Grafting
Zone 2
• Indications
– Delayed treatment making end to end repair
impossible
• Patient factors prevent repair
• Late referral, missed tendon laceration or avulsion
– Supple joints with adequate passive ROM

37. 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

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

39. 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

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

41. 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

42. Single Stage Tendon Grafting
Zone 2
• Setting tension
– GA
• With wrist neutral
• Fingers fall into semi flexed position (slightly less
than ulnar neighbour), allowing estimation of
tension
– Local anesthesia, active flexion
– Electrical stimulation
• Bunnel – “tendons shrink”
• Pulvertaft – “tendons stretch”

43. 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

44. 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

45. 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

46. 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

47. 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)

48. 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

49. 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

50. 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

51. 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

52. 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

53. 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

54. 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)

55. Pulley Reconstruction

56. 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

57. 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

58. Tenolysis
• Timing
– 3-6 mos. Post repair (minimum)
– Plateau with physiotherapy
• Anesthesia
– Local with sedation
• Allows patient participation
• Tests adequacy of release
• Motivates patient

59. Tenolysis
• Technique
– Zig zag incisions
– Adhesions divided maintaining non-limiting
adhesions
– Pulleys reconstructed as needed
• If extensive or not possible convert to staged
reconstruction
– Immediate motion postop.