Flexor tendon injuries(1)

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  • At the wrist level ten structures pass through the carpal tunnel
    4xfds, 4xfdp, fpl and median nerve
    Bordered by:hamate, triquetrum and pisiform and ulnarly
    Scaphoid and trapezium radially
    Roof = flexor retinaculum
    Consists of three components – the the deep forearm facsia, the transverse carpal ligament (which traverses from the scaphoid tuberosity and trapezial beak radially to the hook of the hamate and pisiform ulnary) and the distal aponeurosis btw the thenar and hypothenar muscles
  • Pulleys
    A2 and a4 (most biomechanically important) arise from periosteum of proximal aspect of proximal phalanx, and middile aspect of middle phalanx (respectively)
    A1 a3 and a5 (joint pulleys) arise from volar plates of mp, pip and dip joints respectively
    Intervening cruciate pulleys (c1 c2 and c3) are thin and collapse to allow annular pulley approximation during flexion
  • In the palm FDS is superficial to FDP
    In the proximal sheath fds divides to allow fdp to pass through and go on to insert at the base of the distal phalanx
    Fds the reunites at camper’s chiasm before dividing into two slips of insertion on the base of the middle phalanx
  • Zone 1: distal to FDS insertion
    Zone 2: FDS insertion proximal beginning of flexor sheath
    Previously “no man’s land”
    Zone 3: distal edge of TCL to flexor sheath origin
    Zone 4: carpal tunnel
    Zone 5: distal portion of forearm
  • Generally a combination of zig zag or mid lateral incisions are used
    Depend on
    Direction of initial laceration
    Need to expose other injured structures
    Surgical preference
    Little advantage to limiting exposure
    Avoid crossing jt creases at rigth angles
  • 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
    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
    Type 3: large bony fragment retracts to A4 level
    Bony reduction and fixation of fragment
  • 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
    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
    Type 3: large bony fragment retracts to A4 level
    Bony reduction and fixation of fragment
  • 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
    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
    Type 3: large bony fragment retracts to A4 level
    Bony reduction and fixation of fragment
  • 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
    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
    Type 3: large bony fragment retracts to A4 level
    Bony reduction and fixation of fragment
  • Flexor tendon injuries(1)

    1. 1. Flexor Tendon Injuries
    2. 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. 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. 4. Anatomy • Extrinsic flexors – Superficial group • PT, FCR, FCU, PL • Arise from medial epicondyle, MCL, coronoid process
    5. 5. Anatomy • Extrinsic Flexors – Intermediate group • FDS • Arises from medial epicondyle, UCL, coronoid process • Usually have independent musculotendinous origins and act independantly
    6. 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. 7. Anatomy • Carpal tunnel – 9 tendons – Median nerve
    8. 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. 9. Anatomy • Camper’s Chiasma
    10. 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. 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. 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. 13. Tendon Healing • Factors affecting tendon healing, and adhesion formation – Surgical technique • decreased vascularity • gapping – Postoperative motion (passive, active)
    14. 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. 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. 16. Diagnosis • History
    17. 17. Diagnosis • History
    18. 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. 19. Zones of Injury FDS Insertion Flexor Sheath (proximal) TCL (distal edge) Carpal Tunnel
    20. 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. 21. Incisions • Factors – Avoid crossing joints at 90 deg. – Preference – Existing lacerations – Need to expose other structures
    22. 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. 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. 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. 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. 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. 27. Tendon Excursion
    28. 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. 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. 30. FDP Avulsions Leddy and Packer
    31. 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. 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. 33. FDP Avulsions - Type 3: large bony fragment retracts to A4 level - Bony reduction and fixation of fragment
    34. 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. 35. Reconstruction
    36. 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. 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. 38. Single Stage Tendon Grafting Zone 2 • Technique – Graft donors • Palmaris longus • Plantaris • Long toe extensors • (FDS) • (EIP) • (EDM)
    39. 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. 40. Single Stage Tendon Grafting Zone 2 • Technique – Distal juncture
    41. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 55. Pulley Reconstruction
    56. 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. 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. 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. 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.

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