Overview of flexor tendon surgery

1. Flexor Tendon Injuries
Mr Vaikunthan Rajaratnam
Hand Review Course 19 Aug 2022
http://tinyurl.com/HandTendon

2. Learning
Objectives
• Understand and describe the
anatomy of the flexor tendon
system in the hand and its
relevance in surgery
• Describe and relate the normal
physiology of the tendon and its
implications in injury
• Understand the reaction of
tendon to injury and its healing
process and its implications in
surgery and rehabilitation

3. Flexor tendon anatomy, biology
of tendon healing

4. ANATOMY

5. Our results demonstrate that A2 and A4 absence did
not produce major bowing if adjacent annular pulley
are intact. This has significant impact during flexor
tendon surgery in zone 1 and 2 and the practice of
venting of A2 and A 4 pulleys.

7. Biology
• Tendon nutrition
1. Blood supply provided
through the vincular
circulation
2. Synovial fluid
• FPL does not have a
vinculum >>> can
tolerate more tendon
advancement without
disturbing its blood supply

9. Tendon Healing
Three mechanisms
1. Extrinsic: From
surrounding tissue
(epitenon fibroblast),
for gap healing
2. Intrinsic: Within the
tendon (tenoblast,
stimulated by
movement
3. Combination

10. Tendon Healing
Phases
1. Inflammatory; Week 1
2. Fibroblastic; week 2-4
3. Remodelling; > week 4
Repair weakest at 2 weeks

11. Assessment
• Previous Hx: - Injury
- Soft T. Contracture
- Joint stiffness
- Nerve dysfunction
• PMH; DM, skin conditions, medication,…
• SH: Alcohol, smoking, occupation (recon.)
Socio-economic background

12. Assessment
• ATLS
• History:
1. Nature; knife, glass,
saw, roller, etc.
2. Position of the finger
3. Date and time
4. Environment

13. Assessment
Clinical Examination
Look …..
• Hand/Finger posture (Cascade)
• Both tendon >> full extension
• FDP only >>> extended DIP
• FDS only >>>> No change

14. Assessment
Feel ….
• Empty synovial sheath
• Loss of tendon tension
Move ….
• No tenodesis effect in
passive wrist movement
• Gentle compression on
forearm (ulnar half at
the junction middle and
distal thirds)

15. Assessment
Beware
• Independent FDP index >>>(Pulp to pulp test)
• Tendon anatomical variation: - Deficient FDS
little finger (35%)
- No FDP little finger
• Cut FDP at the wrist >>> normal action
• Partial cut; - Common in FPL
- Painful
• Neuro-vascular injuries
• Others

16. Assessment
Active movement
• FDP
• FDS
• FPL

17. Assessment
X-ray
• Avulsion fracture
• F.B
• Other injuries

18. Zone 1
• Leddy type I – treat within 3 weeks
• type II and III treatable even after 6 weeks.
• Ultrasound helpful in locating the proximal
stump.
• Microsuture anchors or ORIF if bone fragment
• Ensure tendon-bone contact before final knot-
tying.
• Too tight repair - quadrigia.
• > Two-strand repair techniques

20. Leddy Packer Type III

22. Primary Repair of Flexor Tendons
Verdan, Claude E, JBJS. 42(4):647-657, June 1960
• Clean & Fresh
• Excising FDS
• Precise FDP repair core and epitendinous stitches
• Repair the sheath
• Detension repair site with transverse 2 pins
• Consider secondary tenolysis

23. Principles of repair
Muscle relaxation
Adequate but minimal
exposure
4-6 core sutures sufficient
grasping
Coaptation without
gapping and bunching
Epitendinous suture
No impingement on
pulley

24. Tendon Suture

25. Zone 2
< 3 weeks Primary repair
>6 weeks old - recon
Tendon retrieval
Strong repair site vs gentle
passive range-of-motion
therapy
< 1 cm of FDP stump
advancement and repair to
bone
slips of the FDS special
techniques, and needles
Post Op AROM ?
Frayed tendon end
debridement
A2 and A4 myth??

26. Tang, J.B., 2018. New Developments
Are Improving Flexor Tendon Repair:
Plastic and Reconstructive Surgery
141, 1427–1437.

27. The proposed algorithm for pulleys and FDS management
according to the subzone of tendon lesion
Giesen, T et al 2018. Flexor tendon repair in the hand with the M-Tang technique (without
peripheral sutures), pulley division, and early active motion. J Hand Surg Eur Vol 43, 474–479.

28. Primary Flexor Tendon Repair with Early Active
Motion: Experience in Europe
• A 6-strand core suture is performed using the M modification of
Tang’s original technique.
• No circumferential suture is added after a 6-strand core suture.
• The pulleys are divided as much as needed to allow free excursion
of the repaired tendon within the tendon sheath, including, when
necessary, full division of the A4 or A2 pulley.
• To avoid the repaired structures within the sheath being too bulky,
the authors generally repair only half of the flexor digitorum
superficialis, resecting the other half. In zone 2C, and in specific
cases, the flexor digitorum superficialis is excised completely.
• Rehabilitation is controlled active motion, but with modifications.
Giesen, T., Calcagni, M., Elliot, D., 2017. Primary Flexor Tendon Repair with Early
Active Motion: Experience in Europe. Hand Clinics, Hand Surgery in Asia and
Europe 33, 465–472

29. A 2, 4 and 6 core tendon suture of 4/0 nylon and standard 6/0 epitendinous sutures
were placed by a consultant hand surgeon on the intact FDP tendon in Zone 2
• The increase in volume of the
tendon by placement of the suture
• Space between tendon and pulley in
the flexor sheath
• Complete obstruction of the tendon
passage through the pulley system
after sutures
Index finger/ A0:
Volume of pulley 386.3 mm3
volume of tendon + suture 287.1mm3
Little finger/ A1:
Volume of pulley: 124.9 mm3
Volume of tendon + suture: 148.3 mm3
FDP
FDS
PHALANX

30. WALANT and tendon surgery
• there are no evidence about effective positive
outcome on the results of surgical repair of
flexor tendon injuries between Walant
anaesthesia and traditional anaesthesiologic
technique.
Orthopedic Reviews 2020; volume 12(s1):8668

31. Biological Amnion Prevents Flexor
Tendon Adhesion
• freeze-dried amniotic membrane
transplantation was applied to promote
healing of the flexor tendon in zone II and
prevent adhesion.
• 89 patients 160 injured fingers
Liu C, Bai J, Yu K, Liu G, Tian S, Tian D. Biological Amnion Prevents Flexor
Tendon Adhesion in Zone II: A Controlled, Multicentre Clinical Trial. BioMed
Research International. April 2019:1-9. doi:10.1155/2019/2354325

32. Biomechanical Analysis Using
Barbed Suture
• The use of the barbed sutures in the
Asymmetric repair technique flexor
tendon, whilst more time consuming, has
shown promising improvement to its
biomechanical performance
Lee JS, Wong Y-R, Tay S-C. Asymmetric 6-Strand Flexor Tendon Repair –
Biomechanical Analysis Using Barbed Suture. Journal of Hand Surgery
(Asian-Pacific Volume). 2019;24(3):297-302.
doi:10.1142/S2424835519500371
Xing Fu Hap D, Rung Wong Y, Rajaratnam V. The use of barbed sutures in the
Pulvertaft weave: a biomechanical study. Journal of Hand Surgery (European
Volume). 2020;45(10):1055-1060. doi:10.1177/1753193420909452

33. Neiduski, et al 2019. Flexor tendon rehabilitation in the 21st century: A systematic review.
Journal of Hand Therapy, SI: Evidence Updates 32, 165–174.
• Place and hold exercises
provide better outcomes
than passive flexion
protocols
• Active, functional
performance should be
consistently used to
evaluate outcomes.

34. Tendon Rehab
https://www.youtube.com/watch?v=P5GuO2Kb3sI

35. Outcomes

45. 2nd Stage

50. Results 2 stage graft
https://www.youtube.com/watch?v=By5LOOKtvO0