05 hand tendon

Department of Orthopaedics

Seminar on: Flexors & extensor tendon injuries of hand.

Chairperson and moderator: Prof. & HOD: Dr. Kiran Kalaiah

Presenter : Dr. Yashavardhan.T.M

Introduction. Tendon injuries are the second most common injuries of the hand and

therefore an important topic in trauma and orthopaedic patients. “A glistening structure between muscle & bone which transmit force from

muscle to the bone’” Paratenon: Loose areolar tissue encasing tendon in low mechanical stress

area Tendon sheath: a dense fibrous tissue tunnel enclosing tendon in high

mechanical stress area 70% collagen (Type I) Extracellular components • Elastin • Muco-polysaccharides (enhance water-binding capability) Endotenon – around collagen bundles Epitenon – covers surface of tendon Paratenon – visceral/parietal adventitia surrounding tendons in hand

Most injuries are open injuries to the flexor or extensor tendons, but less frequent injuries, e.g., damage to the functional system tendon sheath and pulley or dull avulsions, also need to be considered.

After clinical examination, ultrasound and magnetic resonance imaging have proved to be important diagnostic tools. Tendon injuries mostly require surgical repair, dull avulsions of the distal phalanges extensor tendon can receive conservative therapy.

Injuries of the flexor tendon sheath or single pulley injuries are treated conservatively and multiple pulley injuries receive surgical repair. In the postoperative course of flexor tendon injuries, the principle of early passive movement is important to trigger an "intrinsic" tendon healing to guarantee a good outcome.

Many substances were evaluated to see if they improved tendon healing; however, little evidence was found. Nevertheless, hyaluronic acid may improve intrinsic tendon healing

Anatomical position

Flexors muscles: FDP and FDS tendons have fibrous sheaths on the palmar aspect of the digits

Fibrous arches and cruciate (cross-shaped) ligaments, which are attached posteriorly to the margins of the phalanges and to the palmar ligaments hold the tendons to the bony plane and prevent the tendons from bowing when the digits are flexed. The tendons are surrounded by a synovial sheath.

Flexor tendon system consists of intrinsic and extrinsic components Extrinsics: FDP: flexing the DIP joint FDS: Flexing the PIP Joint FPL: Flexing the IP joint of the thumb Intrinsics: Lumbricals: Flex the MCP joints and Extend the IP joints FDP inserts on base of distal phalanx FDS inserts on sides of middle phalanx FPL inserts on proximal portion of the distal phalanx

INTEROSSEIUS, BLOOD SUPPLY & NERVE SUPPLY

Pulleys of flexour Synovial sheath is reinforced by a system of fibrous pulleys 5 annular pulleys (A) and 3 Cruciform pulleys (C) A1: 8-10 mm over MCPJ A2: 18-20mm over proximal phalanx A3: 2-4 mm over PIPJ A4: 10-12mm over middle phalanx A5: 2-4 mm over DIPJ C1, C2, C3 proximal to A3, A4, A5 Allow shortening of the pulley system in flexion A2 and A4 are considered most important. Their disruption leads to bowstringing, reduced mechanical efficiency and decreased flexion. Function: increase the mechanical efficiency by preventing bowstringing

ZONES OF FLEXOR TENDON INJURY

Zone I: Between insertion of FDP and FDS Zone II: From insertion of FDS to A1 Pulley Zone III: Between A1 pulley and distal limit of carpal

tunnel Zone IV: Within the carpal tunnel Zone V: Between the entrance of Carpal tunnel and

musculo-tendinous junction.

FDS decussation at A1 pulley FDS slips rotate 180°around FDP

Slips rejoin at PIP – Camper’s Chiasma Insert on P2

Tendon nutrition

Parietal paratenon

Passive nutrition by diffusion

Vincula and bony attachments

Direct nutrition

Segmental nutrition

Vincula may prevent retraction

Vascularity dominance is deep surface of tendon

Consider with suture placement

Biomechanically superior to place suture deep

TENDON HEALING

Tendons are capable of actively participating in the repair process through Intrinsic Healing

Tendon healing occurs in three phases: 1. Inflammation 2. Active repair 3. Remodelling• Early tendon motion has significant role in modifying the repair response• Mobilized tendons showed progressively greater ultimate load compared with immobilized tendons• Studies confirm “Wolff’s law” which states that the strength of a healing tendon is proportional to the controlled stress applied to it

ETIOLOGY

sharp object direct laceration (broken glass, kitchen knives or table saws)

crush injury

avulsions

burns

animal or human bites

suicide attempts

motor vehicle accidents

ZONE 1: ZONE OF FDP AVULSION INJURIES

Region b/w middle aspects of middle phalanx to finger tips

Contains only one tendon-fdp

Tendon laceration occurs close to its insertion

Tendon to bone repair is required than tendon repair

Leddy classification of zone I flexor tendon injuries

Type I: tendon retracted into palm (fullness in palm)

Type II: tendon trapped in the sheath at PIP (unable to flex PIP)

Type III: tendon trapped in A4 pully

ZONE II-NO MANS LAND

From metacarpal head to middle phalanx Called so because initial attempts for tendon repair here

produced poor results FDS and FDP within one sheath Adhesion formation risk is amplified at campers chiasma In each finger, the FDS tendon enters the A1 pulley and divides

into two equal halves that rotate laterally and then dorsally. The two slips rejoin deep to the FDP tendon over the distal

aspect of the proximal phalanx and the palmar plate of the PIP joint at Camper's chiasma

Insert as two separate slips on the volar aspect of the middle phalanx.

ZONE III-DISTAL PALMAR CREASE

B/w transverse carpal ligament and proximal margin of tendon sheath formation

Lumbricals origin here prevents profundustendons from over acting

Delayed tendon repairs are succesfull even after several weeks of injury

ZONE IV-TRANSVERSE CARPAL LIGAMENT

Lies deep to deep transverse ligament. Tendon injuries are rare.

FPL and FDM enters its continuous sheath which becomes the radial and ulnar bursae.

The FDS and the FDP also enter a large sheath and lie in the carpal tunnell

ZONE V LIES PROXIMAL TO TRANSVERSE CARPAL LIGAMENT

The Flexor tendons start in the distal third of the forearm at the musculotendinous junction

The superficialis group lies palmar to the conjoined profundus tendon group covered by loose subcutaneous tissue and skin.

SIGNS & SYMPTOMS

Unable to bend one or more finger joints

Pain when bending finger/s

Open injury to hand (e.g., cut on palm side of hand, particularly in area where skin folds as fingers bend)

Mild swelling over joint closest to fingertip

Tenderness along effected finger/s on palm side of hand

Lies deep to deep transverse ligament Tendon injuries are rare

EXAMINATION:

INSPECTION

There is a normal arcade to hand with index finger showing least and little finger showing max flexion If affected finger shows more extension than other digits, chance of tendon injuries are high

Goals of reconstruction

Coaptation of tendons anatomical repair multiple strand repair to permit active range of

motion rehabilitation Pully reconstruction to minimize bow-stringing atraumatic surgical technique to minimize

adhesions strict adherence to rehabilitation protocol.

Timing of flexor tendon repair:

Primary: repair within 24 hours (contraindicated in case of high grade contamination i.e. human bites, infection)

Delayed Primary: 1-10 days when the wound can be still pulled open without incision

Early Secondary: 2-4 weeks.

Late Secondary : after 4 weeks

No repair if less than <25% laceration,

only epitenon repair in 25-50% lacerations,

core suture plus epitenon repair when >50% laceration

Dorsal blocking splint for 6-8 weeks as conservative measure

Ideal tendon repair:

Easy placement of sutures in the tendon

Secure suture knots

Smooth junction of tendon ends without gapping

Minimal interference with vascularity strength

TECHNIQUES

Retrieve the tendon ends through the sheath in an atraumatic manner

Maintain the integrity of the pulley system (especially A2 and A4)

Create “retinacular window” described by Lister for preserving the flexor sheath

Extend the original laceration for better exposure

Zigzag

Mid-lateral

Avoid linear scars that cross flexion crease

Milk the forearm with the wrist and MCP in flexion

Do not attempt blind retrieval more than twice

Make a separate incision if necessary

Use a pediatric feeding tube to retrieve tendon

stump

CORE SUTURE

Six Strand Technique

Tendon Sheath Repair?

Role of diffusion of nutrients from synovial fluid

Tendon within the sheath have an intrinsic capacity for healing

Gelberman and woo in 1990 study on dogs

Reconstruction of the sheath did not significantly improve repaired tendons treated with early motion rehabilitation.

Partial Tendon Laceration

Rupture, entrapment, triggering

Partial laceration involving 60% or less are best treated by early mobilization WITHOUT tenorrhaphy

Profundus Tendon Avulsion

Avulsion of FDP from its insertion by forced hyperextension

Most common in the ring finger

Leddy and Parker classification

Based on the level to which the tendon retracts

Status of the tendon vascular anatomy

Type I

Profundus has retracted proximally into the palm Surgery should be done in 7-10 days before a fixed

muscular contracture develops Least common Distal digital exposure to confirm diagnosis In Type I, a second distal palm incision will be needed Tendon is reinserted into the base of distal phalanx Distally based periosteal flap is raised distal to volar

plate Tendon is sutured through drill holes in the distal

phalanx and button tied over the nail plate

Type II

Profundus retracts to PIP

Disruption of Vinculum Breve

Nutrition is maintained by Vinculum longum

May be repaired up to 3 months

Delay may convert type II into a type I if longumsubsequently ruptures

Type III

Attached bone fragment that fractures off the volar base of distal phalanx

A4 pulley prevents proximal retraction

Both Vinculae are preserved

Type III attention is turned to ORIF

Complications Short term: Infection Injury to neurovascular structures or pulley system Abnormal scarring Long term: Adhesion Rupture Joint contracture triggering Adhesion Most common complication despite early motion protocols Tenolysis when patients progressive gain in digital motion has

plateaued, usually 3-6 months after repair

Quadriga effect

Tendon advancement shortens the FDP & completes the grip before the normal fingers, if the tension on tendon graft is set too high, and limit their flexion and thus week grip

Two stage technique

Create a supple pseudosynovial sheath by implanting a silicone rod

Soft tissue coverage or pulley reconstruction is performed at the first stage

8 weeks later, when psuedosynovial sheath is formed, the rod is replaced by a tendon graft

1. Palmaris longus and plantaris

2. Tendon grafts that include synovial sheath

Tendon Juncture

Pulvertaft weave, with two or more passes through the proximal motor tendon

Distal end may be secured in multiple ways

Tension adjustment

Proximal weave is adjusted

Wrist is extended to flex the fingers into the cascade of the hand

Overcorrect slightly because some stretching occurs after surgery

PULLEY RECONSTRUCTION

Must be done during the first stage

Well-healed pulley reconstruction facilitates early mobilization and gliding of tendon graft

Reconstruction during the second stage increases the likelihood of pulley rupture and adhesion formation

Material used

Autogenous grafts: PL, Plantaris, to extensors, EIP, Extensor retinaculum, fascia lata

Flexor compartment of thumb.

Kleinert Protocol

Combines dorsal extension block with rubber-band traction proximal to wrist

Originally, included a nylon loop placed through the nail, and around the nail is placed a rubber band

This passively flexes fingers, & the patient actively extends within the limits of the splint

Duran protocol

At surgery, a dorsal extension-block splint is applied with the wrist at 20-30° of flexion, the MCP joints at 50-60° of flexion, and the IP joints straight

Extensor Tendons

1. Extrinsic System radial N innervated 2. Intrinsic System ulnar and median N

innervated Extrinsic Extensors Wrist Extensors: ECRL, ECRB, ECU Finger Extensors: EDC, EIP, EDQM Thumb Extensors: APL, EPL, EPB EDC has a common muscle belly with multiple tendons EIP & EDM lie on the ulnar side of the respective EDC

tendon

Thumb Extensors

APL inserts on the metacarpal and radially abducts it

EPB inserts on proximal phalanx and extends MCP Joint

EPL inserts on distal phalanx and extends IP Joint

Testing the Extrinsics:

APL:Palpate with thumb abduction

EPB:MP extension with IP flexion, palpate tendon

EPL:Palpate tendon with retropulsed thumb

EDC:Test with wrist in neutral-extension

Vascularity & Innervation

Volar and dorsal metacarpal vessels

Median nerve supplies radial one or 2 lumbricals

Ulnar nerve supplies ulnar 2 lumbricals

Extensor Apparatus

EDC tendon trifurcates into central slip & 2 lateral slips

Intrinsic extensor tendons join the lateral slips to form the lateral bands

Winslow’s Rhombus

The central slip inserting on the base of the middle-phalanx

and two lateral slips inserting to the distal-phalanx.

Lateral band:

Juncturae Tendinium

Functional roles: spacing of ED tendons force redistribution coordinate

extension MP stabilization Ring finger has least independent extension due to the

orientation of the juncturae

The most common patterns single extensor indicis propriusinserting to the ulnar side of the index extensor digitorumcommunis a single extensor digitorum communis to the index finger a single extensor digitorum communis to the long finger, a double extensor digitorum communis to the ring finger, an absent extensor digitorum communis to the small finger, and a double extensor digiti quinti with double insertions

SAGITTAL BANDS

Stabilize the common extensor during digital flexion over MCPJ Limit the excursion of the common extensor tendon during digital

extension EDC allows extension of MP joint via insertion onto the sagittal

bands There is usually no tendinous insertion of EDC to the dorsal base

of the proximal phalanx No MP joint hyperextension: EDC extends MP, PIP, and DIP joints

even in the absence of intrinsic muscle function. INTRINSIC PARALYSIS: “slack” develops in EDC system distal to the

sagittal bands all producing a flexion posture at PIP and DIP joints, the “claw” finger.

Transverse & oblique fibres of InterosseousHood

Transverse & oblique fibres of Interosseous Hood

1) EDC Tendon

2) Central Slip

3) Lateral Slip

4) Intertendinous Connection

5) Volar Interosseous Muscle

6) Lumbrical Muscle

Triangular Ligament

Connects both lateral bands over the middle phalanx.

• Limits the volar and lateral shifting of the

lateral conjoined extensor tendon during

digital flexion

• In boutonniere deformity; elongated

• In fixed swan neck deformity; retracted

Retinacular Ligament

Lateral continuation of the triangular ligament extending from the lateral margin of the lateral conjoined extensor tendon to PIPJ articular volar plat

Extensor Tendon Injury

Extensor apparatus Extrinsic muscles (ED, EI, EDM)

Intrinsic Muscles ( Lumbricals and Interossei)

Fixed fibrous structures.

Zone 1

• Mallet finger – persistent flexon of distal phalanx

• Closed: splinting 6-8 weeks

• Open: suture repair, Soft tissue reconstruction

Pullout Wire and K pin

Zone II injury- Middle Phalanx Level:

• Repair by interrupted suture.

• Immobilization for 5-6 weeks

• DIP joint in extension

• PIP joint left free

Zone III injury- PIP joint level

Most complex anatomically and physiologically

Causes two deformities

Boutonniere disruption of central tendon

Closed: splinting MCP and PIP in hyperextension for 6 weeks

Open: suture repair (figure of 8 suture)

Swan Neck excessive traction of central tendon

Closed: splinting DIP & Open: suture repair

Zone IV injury-

shaft of proximal phalanx level

Repair relatively easy

Adhesion is the problem

Zone V injury – MP joint level. Closed: splinting, 45 extension at wrist and 20

flexion at MCP & Open: suture repair by 5.0 prolene

Zone VI injury- Metacarpal level Better prognosis than in fingers

All structures, even inter-tendinous band should be repaired.

Core type suture possible. Delayed suture is possible.

Zone VII- wrist level Extensor tendons are under dorsal retinaculum. Retinaculum

should be repaired or partially preserved. Adhesion is the Grasping core suture should be used. Immobilization for 5-6 weeks.

IMMOBILIZATION

Keep the tendon in a shortened position through splinting or casting

Tendons immobilized for 3 weeks

In week 4, gentle active motion of the repaired tendon is introduced

Rehabilitation depends on zone of injury

IMMOBILIZATION

INJURIES IN ZONES PROXIMAL TO MCPs

INJURIES IN ZONES DISTAL TO MCPs

May be immobilized for 3 weeks.

Afterwards, finger may be placed in removable volar splint between exercise periods for 2 weeks

Progressive ROM after 3 weeks

If full flexion is not regained rapidly, dynamic flexion may be started after 6 weeks

Require a longer period of immobilization (usually 6 weeks)

A progressive exercise program is initiated

Dynamic splinting during day and static splinting at night to maintain extension

EARLY PASSIVE MOTION

Extensors are held in extension by dynamic, gentle rubber band traction, and the patient is allowed to actively flex the fingers—passively moving repaired extensor tendons

EARLY ACTIVE MOTION

Early active short arc program (developed by Evans) allows tendon to actively move 3 days after surgery

Therapist must take care to ensure stress applied by early active motion does not overpower strength of surgical repair

Splinting program is complex and specific and requires a skilled occupational therapist

Manchester Short Splint.

Wrist◦ Finishes at dorsal wrist crease

◦ Allows 45 degrees extension

MCPJ◦ 30 degrees flexion

Exercises◦ Commence 4th or 5th day

◦ Motion initiated at DIPJ

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