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.