1. FLEXOR TENDON INJURIES OF THE HAND
Michael Zlowodzki MD
PGY-3 Resident
University of Minnesota
Department of Orthopaedic Surgery

2. OUTLINE Anatomy Clinical assessment
Treatment depending on Zone of injury
Tendon healing biology
Repair techniques
Post-op motion protocols
Delayed grafting

3. ANATOMY

4. FDS ACT INDEPENDANTLY Origin (2 muscle bellies)
Medial epicondyle
Radial shaft
Tendons arise from separate muscle bundles
ACT INDEPENDANTLY

5. FDP SIMULTANEOUS FLEXION OF MULTIPLE DIGITS
Origin: ulna & interosseous membrane
FDP: Common muscle origin for several tendons
SIMULTANEOUS FLEXION OF MULTIPLE DIGITS

6. FDP

7. FDS
FDP
FPL
Lumbricals origin from radial side of FDP

8. CAMPER’s CHIASMA
FDS divides and passes around the FDP tendon, the two portions of the FDS reunite at “Camper’s Chiasma”

10. TENDON SHEETS

11. PULLEYS
Preserve A2 and A4 pulley to prevent bowstringing. NOTE: There is a mistake in this diagram: The C1 pulley is DISTAL to the A2 pulley!

12. TENDON EXCURSION
9 cm of flexor tendon excursion with wrist and digital flexion
only 2.5 cm of excursion is required for full digital flexion with the wrist stabilized in neutral position

13. TENDON EXCURSION MP motion = no flexor tendon excursion
1.5 mm of excursion per 10 degrees of joint motion for DIP (FDP) and PIP (FDS, FDP)

14. BLOOD SUPPLY
Segmental branches of digital arteries which enter the tendon through:
vincula
osseous insertions
Synovial fluid diffusion

15. VINCULAE

16. CLINICAL EXAM

17. FDS: Clinical Exam

18. TENODESIS EFFECT
Passive extension of the wrist does not produce the normal “tenodesis” flexion of the fingers if flexors are injured

19. FDS: Clinical Exam

20. FDP: Clinical Exam

21. FDP RUPTURE
No active DIP motion (present passive DIP motion)

22. ZONES

24. REPAIR ALL COMPLETE TEARS AT ALL LEVELS!

25. ZONE 1 INJURIES: Jersey Finger

26. JERSEY FINGER

27. JERSEY FINGER

28. LEDDY CLASSIFICATION REPAIR WITHIN 7-10 DAYS
Type 1: Retraction into palm
Type 2: Retraction to PIP level
Type 3: Bony avulsion (tendon attached)
Type 4: Bony avulsion (tendon attached not attached to bony fragment)
REPAIR WITHIN 7-10 DAYS

29. TYPES OF REPAIR
Direct repair: if laceration is more than 1 cm from FDP insertion
Tendon advancement: if the laceration is less then 1 cm from insertion.

30. TENDON ADVANCEMENT

31. BUTTON STRONGER THAN SUTURE ANCHORS

33. 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
Quadriga effect

34. QUADRIGA EFFECT If FDP tendon advanced too distally
Entire muscle bells gets pulled distally
Tendon excursion of FDP of other digits is limited
Loss of grip strength

35. ZONE 2 INJURIES

36. ZONE 2 INJURIES
Zone 2: Deep and superficial flexor gliding inside tendon sheets
Traditionally “No man’s land”: Stiffness after repair

37. INJURY: Tendons retract

38. ZONE 2: PARTIAL LACERATIONS

39. Partial laceration No repair if 40% of the tendon intact
Potential complications:
Triggering
Tendon entrapment
Eval for the risk of triggering; debride if necessary
dorsal block splinting for 6 to 8 weeks

40. Conservative treatment:
N=15 patients with zone II partial flexor tendon lacerations of the width of the tendon (Avg. 71%)
Conservative treatment:
Dorsal blocking splint with wrist in 10° of flexion
Immediate guarded active ROM
Splint 4w
No 6w
excellent results in 93% and good in 7%

41. Why not fix a partial laceration when you staring at it in the OR anyway?
Because the dissection necessary to fix it might cause too much scarring, which might outweigh the benefit

42. ZONE 2: COMPLETE LACERATIONS

43. MORE STRANDS: STRONGER & STIFFER REPAIR

44. Ultimate Strength and Repair Technique
Proportional to number of strands
6 and 8 strand repairs strongest
Steep learning curve
Increased bulk and resistance to glide
Increased tendon handling and adhesion formation
May not be necessary for forces of early active motion
4-STRAND REPAIR ADEQUATE STRENGTH WITHOUT COMPLEXITY OF 6-8 STRANDS

45. Proximal Tendon Retrieval

46. Fix FDP and FDS or just FDP?
Why?
Because the blood supply to the FDP tendon is jeopardized if the FDS is not also fixed (due to the vinculae anatomy) (Personal communication: Dr. James House)

48. COMPLICATIONS Stiffness Re-rupture
Tenolysis may be required in an estimated 18% to 25% of patients
No earlier than 3 months after repair
If no ROM improvement for 1-2 months

49. ZONE 3 INJURIES

50. Lumbrical muscle bellies usually are not sutured because this can increase the tension of these muscles and result in a “lumbrical plus” finger (paradoxical proximal interphalangeal extension on attempted active finger flexion).

51. ZONE 4 INJURIES

52. ZONE 4: Carpal Tunnel

53. TENDON HEALING

54. Flexor tendon healing
Intrinsic healing: occurs without direct blood flow to the tendon
Extrinsic healing: occurs by proliferation of fibroblasts from the peripheral epitenon
adhesions occur and limit tendon gliding

55. PHASES OF TENDON 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 - 4months)
TENDON DAYS

56. BRUNNER INCISION

59. SUTURE TECHNIQUES

61. Kessler

62. Modified Kessler (1 suture)
Advantage: Only one node inside the repair site. Easier to use a monofilament suture like a 4.0 Proline to re-approximate tendon edges.

63. Kessler-Tajima (2 sutures)

64. SUTURE MATERIAL Non-absorbable
Most authors prefer a synthetic braided 3.0 or 4.0 suture, usually of polyester material (Mersilene, Tycron, Tevdek)
However, monofilament sutures like nylon and wire are also used (e.g. Proline)
Additional running, circumferential 5-0 or 6-0 nylon is used often

65. IN: Interference with healing
SUTURE KNOT LOCATION
IN: Interference with healing
OUT: Interference with tendon gliding

66. SUTURE KNOT LOCATION FEW STUDIES – NO CONSENSUS
Knots outside superior in one in vitro study (Aoki)
Statistically significant increase in tensile strength at 6 wks with knots inside technique in canine model (Pruitt)
FEW STUDIES – NO CONSENSUS

67. SHEAT REPAIR NO CLEAR ADVANTAGE ESTABLISHED Advantages Disadvantages
Barrier to extrinsic adhesion formation
More rapid return of synovial nutrition
Disadvantages
Technically difficult
Increased foreign material at repair site
May narrow sheath and restrict glide
NO CLEAR ADVANTAGE ESTABLISHED

68. POST-OP REHAB

69. HISTORICAL Bunnel (1918) Postoperative immobilization
Active motion beginning at 3 wks postop.
Suboptimal results by today’s standards
Improved suture material/technique as well as postoperative rehabilitation protocols

70. STIFFNESS
RUPTURE

71. Too much motion
To little motion
RUPTURE
STIFFNES

72. POST-OP PROTOCOLS GOAL: FULL ACTIVE ROM @ 10-12 weeks
Kleinert: Active extension, passive flexion by rubber bands
Duran: Controlled Passive Motion Methods
Strickland: Early active ROM
GOAL: FULL ACTIVE weeks

73. Kleinert Protocol

74. Duran protocol

75. DURAN PROTOCOL Dorsal Splint in 20 deg wrist flexion No rubber bands
Passive flexion
Designed in response to notion 3-5mm of tendon gliding sufficient to prevent restrictive adhesions

76. Rehabilitation Strickland (1980s-1990s)
Uses a 4 strand repair with epitendinous suture
Dorsal blocking splint with wrist at 20 deg of flexion
Supervised active ROM starts POD #3
Unsupervised AROM at 4 weeks
Rarely used, because it requires a pretty extensive “bulky” repair to allow for early active ROM. A lot of surgeons thinks that too much suture material may be problematic for tendon healing

77. 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
Role for Botox?

78. DELAYED RECONSTRUCTION

79. Single Stage Tendon Grafting: Indications
Segmental tendon loss
Delay in definitive repair (>3-6 weeks)
Need
Full PROM
Competent pulleys

80. Single Stage Tendon Grafting Zone 2 Injuries
Graft donors
Palmaris longus
Plantaris
Long toe extensors
(FDS)
(EIP)
(EDM)

81. Two Stage Reconstruction Indications
Extensive soft tissue scarring
Crush injuries
Associated fractures, nerve injuries
Loss of significant portion of pulley system

82. Two Stage Reconstruction: Stage 1
Excision of tendon remnants
Hunter rod then placed through pulley system and fixed distally
Reconstruct pulleys as needed if implant bowstrings

83. Two Stage Reconstruction: Stage 2
Implant removal and tendon graft insertion
FDS transfer from adjacent digit described
Postop
Early controlled motion x 3 wks, then slow progression to active motion

84. 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

85. COMPLICATIONS

86. COMPLICATIONS Joint contracture Adhesions Rupture Bowstringing
Infection

87. MY PREFERENCE (Based on this review and the subsequent feedback)

88. MY PREFERENCE Fix FDS and FDP asap - ideally within 7 days of injury
3.0 Proline modified Kessler stitch (one node inside)
If tendon is big enough use another 4.0 Proline modified Kessler stitch
Additional 5.0 Proline running epitendinous suture
Kleinert or Duran post-op protocol

89. OITE Question

90. Answer

91. OITE Question

92. OITE Imaging

93. Answer

94. THANK YOU Special thanks to Daniel Marek MD for borrowing some of the slides