TENDON INJURIES OF HAND
TENDON INJURIES OF HAND
Maj Vivek Mathew Philip
ANATOMY
FLEXOR TENDON INJURIES
EXTENSOR TENDON INJURIES
SPECIAL CONDITIONS
INTRODUCTION
Anatomical position
INTRODUCTIONDefinition:
Tendon injuries are common
Exact incidence is unknown
Surgeons goal: Expeditious return to full function
CARPAL TUNNEL
FDP and FDS tendons have fibrous sheaths on the palmar aspect of the digits Extent:ant to MCPJ to the distal phalanges; Fibrous arches and cruciate (cross-shaped) ligaments, which are attached posteriorly to the margins of the phalanges and to the palmar ligamentshold 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.
EXTENSOR HOODS
ED and EPL tendons expand over the proximal phalanges to form complex 'extensor hoods' or 'dorsal digital expansions' .EDM,EIP and EPB endons join these hoods. triangular in shape, with: the apex attached to the distal phalanx; the central region attached to the middle phalanx base wrapped around the sides of the MCPJ and corners attach mainly to the deep transverse metacarpal ligaments
EXTENSOR HOODS
The lumbrical, interossei, and abductor digiti minimi muscles attach to the extensor hoods.
In the thumb, the adductor pollicis and abductor pollicis brevis muscles insert into and anchor the extensor hood.
FUNCTION OF DDE
INTEROSSEI
BLOOD SUPPLY
BASIC PRINCIPLES (Sterling Bunnell)
Exact knowledge of pertinent anatomy and physiology
Sound clinical judgment
Strict atraumatic surgical technique
No Mans Land Area within digital flexor sheath, advised not to repair tendon injuries in this zone
DILEMMADespite modern advances, good results after flexor tendon repair are not uniformly obtained.
Should both tendons be repaired or just the FDP?
Should the sheath be excised or repaired?
What type of sutures should be utilized?
What type of postoperative motion most beneficial?
ANATOMYThe tendons of the nine digital flexors enter the proximal aspect of the carpal tunnel in a fairly constant relationship. The most superficial tendons are the FDS tendons to the long and ring fingers. Immediately beneath them are the FDS tendons to the index and little fingers. In the deepest layer are four tendons of the FDP and the FPL.
AnatomyFlexor tendon system consists of intrinsic and extrinsic componentsExtrinsics:FDP: flexing the DIP jointFDS: Flexing the PIP JointFPL: Flexing the IP joint of the thumbIntrinsics:Lumbricals: Flex the MCP joints and Extend the IP joints
FDP inserts on base of distal phalanxFDS inserts on sides of middle phalanxFPL inserts on proximal portion of the distal phalanx
GOAL
Primary repair of injured flexor tendons within the digital sheath is currently accepted.
Despite Modern advances, good results following flexor tendon repair is not uniformly obtained.
Control the inevitable scar formation that interferes with the beautiful gliding mechanism within the flexor tendon system
FLEXOR TENDONS
FDP and FDS tendons fibrous sheaths on the palmar aspect of the digits Extent:ant to MCPJ to the distal phalanges; Fibrous arches and cruciate (cross-shaped) ligaments, which are attached posteriorly to the margins of the phalanges and to the palmar ligamentshold 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.
Synovial sheath is reinforced by a system of fibrous pulleys5 annular pulleys (A) and 3 Cruciform pulleys (C)A1: 8-10 mm over MCPJA2: 18-20mm over proximal phalanxA3: 2-4 mm over PIPJA4: 10-12mm over middle phalanxA5: 2-4 mm over DIPJC1, C2, C3 proximal to A3, A4, A5Allow shortening of the pulley system in flexionA2 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
PULLEY BIOMECHANICS
ZONES OF FLEXOR TENDON INJURYZone I: Between insertion of FDP and FDSZone II: From insertion of FDS to A1 PulleyZone III: Between A1 pulley and distal limit of carpal tunnelZone IV: Within the carpal tunnelZone V: Between the entrance of Carpal tunnel and musculo-tendinous junction.Thumb zones:I: Distal to IPJII: from A1 to IPJIII: Thenar eminence
Zone VThe Flexor tendons start in the distal third of the forearm at the musculotendinous junctionThe superficialis group lies palmar to the conjoined profundus tendon group covered by loose subcutaneous tissue and skin.
Zone IVFPL 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 IIIThe Lumbrical muscles originate from the FDP just distal to the carpal canalup to the beginning of the fibroosseous canal
Zone IIThe flexor synovial sheath begins at the neck of the metacarpal.The sheath is a double-wall hallow sealed at both endsFDS is in a single layer volar to FDPEach Tendon splits that diverges and wraps around FDP
Synovium membrane of the flexor tendon consists of two layers:Visceral layer: around the structure within the sheathParietal layer: covers internal aspect of the pulley system
FIBRO-OSSEOUS SHEATH
Allows smooth gliding of the tendon
Facilitates nutrition to the tendon by synovial diffusion
Tendons are enclosed within this sheath and was defined as No Mans Land, because of the generally worse outcome associated with this repair.
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.
Nutrition in Z2
Dual Source:VascularSynovial diffusionVascular: Segmental vessels arising from the paratenon enter the tendons and travel longitudinally between the fasicles.
Vincular SystemFlexor tendon receives blood supply within the tendon sheathEach tendon is supplied by a short Vinculum (Vinculum Breve) and a long Vinculum (Vinculum LongusVBP arises from distal transverse digital artery at DIPVBS & VLP from Central Transverse digital artery at PIPVLS arises just distal to MCP from proximal transverse digital artery
NUTRITIONIn summaryIn distal forearm and palm: Perfusion from longitudinally oriented vessels over the paratenon
Within the digital sheath: Dual source of nutrition:Synovial fluid diffusionVincular systemDiffusion is more important than perfusion
TENDON HEALINGTendons are capable of actively participating in the repair process through Intrinsic Healing
Intrinsic Tendon healing occurs in three phases:
InflammationActive repairRemodeling
Early tendon motion has significant role in modifying the repair response
Mobilized tendons showed progressively greater ultimate load compared with immobilized tendons
Studies confirm Wolffs law which states that the strength of a healing tendon is proportional to the controlled stress applied to it
BASIC PRINCIPLES OF REPAIRAll flexor tendon repairs should be done in the OR
Use of either general or axillary block
Use tourniquet unless contraindicated
Cleanse and debride the wound
POST OPERATIVE THERAPY
Critical part of treatment for flexor tendon repair
Early passive-motion protocols
Early Active motion
EARLY PASSIVE-MOTION PROTOCOLSDorsal blocking splint to maintain wrist and MCP in flexion and block extensionKleinert protocol uses rubber bands to maintain digital flexion while allowing active extensionExtrinsic flexors are relaxed during active extensionActive extension moves the repaired tendon without resistanceWhen the extensors are relaxed,fingers are pulled backin flexion by the rubber bands4-5 weeks active flexion8 weeks resisted flexion
Early Active MotionEarly Active motion is used with increasing frequencyThis protocol requires experienceTherapistSurgeonReliable patientStrong tendon repair
Ideal tendon repair:Easy placement of sutures in the tendonSecure suture knotsSmooth junction of tendon ends without gappingMinimal interference with vascularitystrength
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
TECHNIQUES
Extend the original laceration for better exposure
ZigzagMidlateral
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
Suture TechniqueSuture materialNon reactivePliableSmall caliberStrongEasy to handle
Common material: Ethibond, Nylon, proline
The strength of the tendon repair is proportional to the number of core sutures that cross the tenorrhaphy site.
6-0 proline epitendinous suture is addedtidy up the repair
Contributes to the strength of the repair
McCarthy in 1996 survey: 72% used this technique
Six Strand Technique
Tendon Sheath Repair?Role of diffusion of nutrients from synovial fluidTendon within the sheath have an intrinsic capacity for healingGelberman and woo in 1990 study on dogsReconstruction 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 AvulsionAvulsion of FDP from its insertion by forced hyperextensionMost common in the ring fingerLeddy and Parker classificationBased on the level to which the tendon retractsStatus of the tendon vascular anatomy
Type IProfundus has retracted proximally into the palmSurgery should be done in 7-10 days before a fixed muscular contracture developsLeast common
Distal digital exposure to confirm diagnosisIn Type I, a second distal palm incision will be neededTendon is reinserted into the base of distal phalanxDistally based periosteal flap is raised distal to volar plateTendon is sutured through drill holes in the distal phalanx and button tied over the nail plate
Maintain flexion of the wrist and MCPJ in a dorsal blocking splintBegin early passive motionActive motion in 3-4 weeks
Type IIProfundus 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 longum subsequently ruptures
Type IIIAttached bone fragment that fractures off the volar base of distal phalanxA4 pulley prevents proximal retractionBoth Vinculae are preserved
Type III attention is turned to ORIF
COMPLICATIONS
Short term:InfectionInjury to neurovascular structures or pulley systemAbnormal scarring
Long term:AdhesionRuptureJoint contracturetriggering
ComplicationsAdhesionMost common complication despite early motion protocolsTenolysis when patients progressive gain in digital motion has plateaued, usually 3-6 months after repair
Tendon RuptureNoted by the patient at popping in the hand7-10 days postop when tensile strength is weakestMRI may help in diagnosisFlexion contractureFDP advancement more than 1 cm may lead to flexion contracture and weakened hand grip because of quadrigia effect
Flexion contractureFDP advancement more than 1 cm may lead to flexion contracture and weakened hand grip because of quadrigia effect
Quadriga effectOver advancement of the FDP - weak grasp in remaining fingers due to FDP tethering; - if one FDP is tethered, the others can not shorten; - there is loss of flexion in other digits and patient may be unable to make a full fist
Triggering and entrapmentEspecially when sheath is not repairedPost traumatic regional pain syndromesCold intoleranceRSD
LATE RECONSTRUCTION
Indications:Primary repair is not possibleSegmental lossLoss of the pulley systemCompromised woundDelayed diagnosisScarring and rupture
Consideration for flexor tendon reconstructionBoyes grading scale of flexor tendon injury provides a guideline in determining the achievable outcome after flexion tendon reconstruction
The position of the digit to be reconstructed should be considered
Ulnar ring and small digits need complete flexion to provide strong grip
Full flexion of radial digits are less important because they are used for precision pinch
Full flexion of the thumb is less important than providing a stable and sensate thumb with adequate length
Prerequisite for flexor tendon reconstructionAdequate soft tissue coverageDigital vascularityHealed fracturesPassively supple jointsReturn of sensibility
Reconstruction ModalitiesTenolysisTendon advancementTendon transferTendon grafts with or without creation of artificial tendon sheath by silicon rod implantation
AlternativesAmputationJoint fusionTenodesisCaspulodesis
Tendon graftingUsed when injury has resulted in a tendon gap
Can be carried out in one or two stages
One stageAcute trauma: segment of flexor tendon lost in a clean, vascularized wound with intact pulley
Tenolysis: when tendon is deemed inadequate to permit immediate postoperative motion
TWO STAGEDirect repair is not possible
Scarred tendon bed in which primary tendon grafting has a low chance of gliding
Reconstruction of profundus tendon when sublimis is intact and there are existing scars
Two stage techniqueCreate a supple pseudosynovial sheath by implanting a silicone rodSoft tissue coverage or pulley reconstruction is performed at the first stage8 weeks later, when psuedosynovial sheath is formed, the rod is replaced by a tendon graft
Palmaris longus and plantaris
Tendon grafts that include synovial sheathToe extensors Other donorsEDC to index,EDL to 2nd, 3rd and 4th toes, EIP /EDQ
Tendon JuncturePulvertaft 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 stageWell-healed pulley reconstruction facilitates early mobilization and gliding of tendon graftReconstruction during the second stage increases the likelihood of pulley rupture and adhesion formationMaterial usedAutogenous grafts: PL, Plantaris, to extensors, EIP, Extensor retinaculum, fascia lata
Rehabilitation
Controlled passive motion protocol started immediately
Active motion at 3 weeks
Strengthening exercised at 6 weeks
Functional Anatomy of Extensor Tendons
Intrinsic System ulnar and median N innervatedExtensor TendonsExtrinsic Systemradial N innervated
Extrinsic ExtensorsWrist Extensors: ECRL, ECRB, ECU
Finger Extensors: EDC, EIP, EDQM
Thumb Extensors: APL, EPL, EPB
Finger ExtensorsEDC has a common muscle belly with multiple tendonsEIP & EDM lie on the ulnar side of the respective EDC tendon
93EIP & EDM allow extension of IF and LF independently of EDC.
Thumb Extensors APL inserts on the metacarpal and radially abducts itEPB 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
95
Testing the Extrinsics
Compartments at Wrist
Intrinsic ExtensorsLumbricals
Interossei: 4 dorsal, 3 volar
Vascularity & Innervation:
Volar and dorsal metacarpal vessels
Median nerve supplies radial one or 2 lumbricals
Ulnar nerve supplies ulnar 2 lumbricals
EDC tendon trifurcates into central slip & 2 lateral slipsIntrinsic extensor tendons join the lateral slips to form the lateral bandsExtensor Apparatus
Lateral Band
Lateral Band
The central slip inserting onthe base of the middlephalanx and two lateral slipsinserting to the distalphalanx.
Winslows Rhombus
Juncturae Tendinium
ANATOMICAL PATTERNS OF THE EXTENSORS TO THE FINGERS
The most common patterns single extensor indicis proprius inserting to the ulnar side of the index extensor digitorum communisa 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 smallfinger, and a double extensor digiti quinti with double insertions.,
JUNCTURAE TENDINIUMFunctional roles: spacing of ED tendons force redistribution coordinate extension MP stabilization
Ring finger has least independent extension due to the orientation of the juncturae
SAGITTAL BANDS
Sagittal Bands Stabilize the common extensor during digital flexion over MCPJ
Limit the excursion of the common extensor tendon during digital extension
Sagittal bands 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.
Interosseous Hood
Transverse & oblique fibers of Interosseous Hood1) EDC Tendon2) Central Slip 3) Lateral Slip 4) Intertendinous Connection5) Volar Interosseous Muscle6) Lumbrical Muscle7) Interosseuos Hood (Transverse)8) Interosseuos Hood (Oblique)9) Lateral band
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2
TriangularLigamentConnects both lateral bands over the middle phalanx
1
65423PIP Joint
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 LigamentTransverse bands:
Lateral continuation ofthe triangular ligamentextending from thelateral margin of the lateral conjoinedextensor tendon to PIPJarticular volar plate
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MechanicsExtensor apparatus produces finger extension & collaborates in finger flexion
Dynamics of ExtensionExcursion Total Wrist MP PIP DIP Index 54mm 38 15 2 0Middle 55 41 16 3 0Ring 55 39 11 3 0Little 35 20 12 2 0Thumb 58 33 7 6 8
Finger Extension Combined action of long extensor & intrinsics
HyperextensionExtension of IPJs with hyperextension of MCPJ can be possible because of the strong traction of intrinsics (lumbricals)
Linked ExtensionNormal conditions extension of MP extension of DP
Extensor zones as described by Verdan
Repair Techniques
Repair Techniques
Doyle[25] proposed the following techniques for extensor tendon repair: Zone 1 (DIP joint): Running suture incorporating skin and tendon.Zone 2 (middle phalanx): Running 5-0 stitch near cut edge of tendon, completed with basket-weave or Chinese fingertrap type of cross-stitch on the dorsal surface of the tendon .Zones 3 through 5 in fingers, and zones 2 and 3 in thumb: Modified Kessler suture of 4-0 synthetic material in the thickest portion of the tendon. A 5-0 cross-stitch tied to itself at the beginning and end is run on the dorsal surface of the tendon Zones 6 and 7: Same as for zones 3 through 5 except the cross-stitch is run around the entire circumference of the tendon, if feasible
Injuries to Specific Zones
Mallet FingerDue to disruption of terminal tendon
Caused by forced flexion, hyperextension or torsion
Can result in 20 Swan Neck Deformity
Early or late volar subluxation of DIP
Closed Rupture of Extensor Tendon with Avulsion Fracture of P3
Mallet FingerClassification - Lange & Engber
I.Extensor tendon injurya. rupture/attenuationb. lacerationII.Extensor avulsionIII.Mallet #a. transepiphyseal # of childrenb. hyperextension mallet without subluxationc. hyperextension mallet with subluxation
Hyperextension Splint A tendinous injury generally can be improved byextension splinting up to 6 months from the time of injury
Splints for Mallet
Mallet Surgery
Direct repair + K-wire Pullout wire tied over padded button + K-wire Central slip tenotomy Tenodermodesis Tendon grafting - extensor or ORL Extension block wiring (Ischiguro) Arthrodesis
Direct repair + K-wireFailure of conservative treatment
Exposure and Direct Repair of the Tendon
DIP joint pinned in extension
Pullout Wire and K pin
Zone II (P2) InjuryUsually lacerations
Result in Mallet deformity
Approximate with horizontal loop sutures
DIP pinning or splint
Post op as in Mallet
Swan-neck
Zone III Injury
Injury over PIP JointCentral slip disruption
Boutonniere deformity
Zone IV InjuryUsually partial as P1 is rounded
Not much retraction of cut ends
Repair / Splinting for 3-4 weeks or 6 wks if total laceration
Zone V InjuryExtensor lag usually minimal due to incomplete injury of sagittal band
Simple Lacerations direct repair
Extensor dislocations pathology in the proximal radial sagittal band. Classically involves MF
Closed Sagittal Band InjuriesRayan GM, Murray D J Hand Surg 1994
Treatment of Sagittal Band InjuriesConservative volar splint, cast, buddy taping for 4-6 wks. Results satisfactory when treated within 3 wks
Surgical centralization of tendon by repair or reconstruction of the radial band
Composite Tissue loss in Zone VIMeticulous debridement and Flap cover with primary / secondary extensor reconstruction
Staged reconstruction with free flaps, silicon tendon implants followed by ext grafts
Single stage primary bone + tendon graft + free flaps Dorsalis pedis tendocutaneous flap
Zone VII InjuryArea under the retinaculum with6 compartments
Problem of retraction, tendon adhesion, bowstringing due to injury to the retinaculum
Closed tendon ruptures are also seen in this zone
Closed tendon ruptures of EPL, EDC mainly reported with Colles #, Smith #, Galeazzi #, ulnar subluxn, Madelung deformity, distal ulna excision, Keinbocks
Proposed to be due to avascular necrosis of the tendon, attrition
Treated by tendon transfers (preferably EIP) or graftingZone VII Injury
Zone VIII InjuriesUsually multiple tendons are affected
Repair at the musculotendinousjunctions are difficult
Associated nerve injuries must be identified
Thumb Tendons Mallet thumb rare EPB anomalies commonplace Delayed rupture of EPL may follow fractureseg. Colles, Galleazi, Smiths, Madelungs deformityEPL repair pitfallsretraction - may require re-routing
Injury to Thumb ExtensorZone I and IIMallet injuries are rare Operative treatment is a good option esp in open lacerationsZone V VIIMCP area is designated zone V Extensor lag usually minimalProximal to zone V, EPL retracts farRepair >1mo requires rerouting EPL from Listers tubercle
Long term results60% has associated injuries
Excellent or good results in 62% (TAM 89% or 2300 ) when not associated with other injuries
45% (TAM 82% or 2120) when associated with other injuries
Distal zones (I-IV) results less favorable
Loss of flexion is the most significant complication
SummaryExtension of digits is an intricate and complex mechanism
Extensor tendon injuries are common
Loss of flexion is significant
The deformity depends on the zone of injury
SummaryZone III/IV injury has a poorer result
Associated injury to joint, bone etc results in poorer results
EPM and EAM gives better results
Thank You