FLEXOR TENDON INJURIES OF THE HAND

Michael Zlowodzki MDPGY-3 Resident

University of MinnesotaDepartment of Orthopaedic

Surgery

OUTLINE

AnatomyClinical assessmentTreatment depending on Zone of injuryTendon healing biologyRepair techniques Post-op motion protocolsDelayed grafting

ANATOMY

FDS

Origin (2 muscle bellies)– Medial epicondyle – Radial shaft

Tendons arise from separate muscle bundles

ACT INDEPENDANTLY

FDP

Origin: ulna & interosseous membrane FDP: Common muscle origin for several

tendons

SIMULTANEOUS FLEXION OF MULTIPLE DIGITS

FDP

FDSFDPFPLLumbricals

origin from radial side of FDP

CAMPER’s CHIASMA

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

TENDON SHEETS

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

PULLEYS

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

TENDON EXCURSION

MP motion = no flexor tendon excursion1.5 mm of excursion per 10 degrees of

joint motion for DIP (FDP) and PIP (FDS, FDP)

BLOOD SUPPLY

Segmental branches of digital arteries which enter the tendon through: – vincula– osseous insertions

Synovial fluid diffusion

VINCULAE

CLINICAL EXAM

FDS: Clinical Exam

TENODESIS EFFECT Passive extension of the wrist does not produce the

normal “tenodesis” flexion of the fingers if flexors are injured

FDS: Clinical Exam

FDP: Clinical Exam

FDP RUPTURE

No active DIP motion (present passive DIP motion)

ZONES

REPAIR ALL COMPLETE TEARS AT ALL LEVELS!

ZONE 1 INJURIES:

Jersey Finger

JERSEY FINGER

JERSEY FINGER

LEDDY CLASSIFICATION

Type 1: Retraction into palmType 2: Retraction to PIP levelType 3: Bony avulsion (tendon attached)Type 4: Bony avulsion (tendon attached

not attached to bony fragment)

REPAIR WITHIN 7-10 DAYS

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.

TENDON ADVANCEMENT

BUTTON STRONGER THAN SUTURE ANCHORS

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

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

ZONE 2 INJURIES

ZONE 2 INJURIES Zone 2: Deep and superficial flexor gliding inside

tendon sheets Traditionally “No man’s land”: Stiffness after repair

INJURY: Tendons retract

ZONE 2: PARTIAL LACERATIONS

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

– 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 removed @ 4w• No restriction @ 6w

– excellent results in 93% and good in 7%

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

ZONE 2:COMPLETE LACERATIONS

MORE STRANDS: STRONGER & STIFFER REPAIR

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

Proximal Tendon Retrieval

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)

FIX FDP AND FDS!

COMPLICATIONS

StiffnessRe-ruptureTenolysis 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

ZONE 3 INJURIES

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).

ZONE 4 INJURIES

ZONE 4: Carpal Tunnel

TENDON HEALING

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

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 WEAKEST @ 10-14 DAYS

BRUNNER INCISION

SUTURE TECHNIQUES

Kessler

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.

Kessler-Tajima(2 sutures)

SUTURE MATERIAL

Non-absorbableMost 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

IN: Interference with healing

OUT: Interference with tendon gliding

SUTURE KNOT LOCATION

SUTURE KNOT LOCATION

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

SHEAT REPAIR

Advantages– 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

POST-OP REHAB

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

STIFFNESS

RUPTURE

Too much motion

To little motion

RUPTURE

STIFFNES

POST-OP PROTOCOLS

1. Kleinert: Active extension, passive flexion by rubber bands

2. Duran: Controlled Passive Motion Methods

3. Strickland: Early active ROM

GOAL: FULL ACTIVE ROM @ 10-12 weeks

Kleinert Protocol

Duran protocol

DURAN PROTOCOL

Dorsal Splint in 20 deg wrist flexionNo rubber bandsPassive flexionDesigned in response to notion 3-5mm of

tendon gliding sufficient to prevent restrictive adhesions

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

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?

DELAYED RECONSTRUCTION

Single Stage Tendon Grafting: Indications

Segmental tendon loss

Delay in definitive repair (>3-6 weeks)

Need – Full PROM– Competent pulleys

Single Stage Tendon Grafting Zone 2 Injuries

Graft donors– Palmaris longus– Plantaris– Long toe extensors– (FDS)– (EIP)– (EDM)

Two Stage ReconstructionIndications

Extensive soft tissue scarring– Crush injuries– Associated fractures, nerve injuries

Loss of significant portion of pulley system

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

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

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

COMPLICATIONS

COMPLICATIONS

Joint contracture Adhesions Rupture Bowstringing Infection

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

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

OITE Question

Answer

OITE Question

OITE Imaging

Answer

THANK YOU

Special thanks to Daniel Marek MD for borrowing some of the slides