· from 2 sources
· blood vessels
· synovial fluid
Blood supply
· from 4 sources
· longitudinal from proximal muscle tissue
· paratenon in palm
· segmental from vinculae in sheath
· from osseous insertion distally
· tendons relatively avascular
· at volar 1/3 as vessels enter tendons dorsally
· between segmental vessels
· synovial fluid is important source of nourishment
· combination of
· intrinsic healing
· extrinsic healing with migration of blood vessels and fibroblasts from peritendinous granulation tissue
· A2 and A4 are most important components of flexor sheath
· A3 not critical unless A2 and A4 lost
· loss of pulleys causes
· tendon bowing
· decreased ROM
· decreased power of flexion
· repair most difficult in Bunnell’s no-man’s land
· zone II
· in fibrous sheath to insertion of FDS tendon
Indications
· recent injury
· can be performed in first few days
· no evidence that should be performed as emergency
· sharp injury
· relatively tidy ends
Structures
· should repair FDS and FDP tendon in all zones if possible
· repair of FDS in zone II increases contents of sheath BUT
· preserves vincular supply to FDP
· provides smooth bed for FDP
· retains independent finger motion
· gives stronger grip strength
· less likely to develop hyperextension deformity of PIP jt
· can be successful with good technique
Other injuries
· associated fractures
· should be stabilised such that motion not impeded
· digital nerve injuries
· should be fixed at same time
Incision
· skin laceration extended
· midaxial incision
· leave neurovascular bundles in situ
· to preserve transverse vessels to vinculae
· Brunner incision
· dictated by existing laceration
Retrieval
· tendon usually retracts into palm
· manoeuvre
· flexion of wrist and fingers
· compression of forearm
· milking of tendon down palm
· passage of tendon retrieval forceps into sheath
· if not able to be retrieved
· transverse incision in DPC
· tendon withdrawn
· suture for eventual repair placed in proximal end
· infant feeding tube passed from injury proximally
· suture passed into tubing
· tendon delivered by withdrawing tube and sutures
· tendon secured with 25-gauge needle transversely through sheath
Sheath windows
· every effort should be made not to violate annular pulleys
· esp. A2 and A4
· windows should be made in cruciate-synovial areas
· L-shaped window (base proximal to form funnel)
· most repairs can be made in C1 interval (between A2 and A3 pulleys over head of P1)
· if < 1 cm distal tendons can be delivered into wound
· another window opened distally
· in C2 interval (between A3 and A4 pulleys over base of P2)
· core sutures inserted
· suture passed under pulley
· tied in original window
FDS spiral
· if FDS cut at mid-point of spiral around FDS, proximal and distal ends both rotate through 90o in different directions
· derotation required prior to repair
Handling
· handle only tendon end with forceps
· avoid trauma to surrounding structures
Suture material
· varies
· braided 4/0 nonabsorbable material probably best for core stitch
· eg. Ethibond
· monofilament 6/0 nonabsorbable material for circumferential stitch
· eg. Prolene
Technique of repair
· varies
Modified Kessler
· probably best
· enter lateral tendon in volar 1/3
· exit 1 cm proximal
· transverse limb superficial to longitudinal suture
· knot tied within repair
Circumferential stitch
· continuous running stitch
· smooths surface
· adds strength
· can place posterior sutures before core stitch tied
Partially cut tendons
· best approach unclear
· tendon weakened by suturing
· can jam, trigger and rupture if untreated
· if < 50% division, excise bevel only
· if > 50% division, repair
Sheath
· unclear whether should close membranous sheath
· scar tissue may adhere to repair
· reduction of sheath diameter may impede smooth passage
· restoration of synovial space may improve healing
· pulleys should be reconstructed if damaged
· can use extensor retinaculum
Considerations
· considerable drop in strength after suture
· at 5 days
· remains 25% weaker for 3 weeks
· scar improved by application of stress
· early passive ROM leads to
· increased tensile strength
· less adhesions
· improved excursion
Requirements
· protection of hand
· tendon glide through sheath for short distance
· controlled forces
Initial
· minimum dressings on palm
· dorsal slab in OR
· wrist flexed 20o
· MCP jts flexed 70o
· IP jts flexed 20o
· elevation in sling
Definitive splint
· dorsal thermoplastic extension blocking splint
· wrist and MCP jts as above
· if rubber band regimen
· hooks on fingernails
· elastic bands from hooks to volar splint
· under bar at DPC
Regimen
· splint and controlled mobilisation for 6 weeks
· all fingers should be involved
· exercises twice daily
Rubber band method
· consists of
· active extension
· passive flexion due to rubber band
· tendon moves
· flexor muscles inactive
· tension on suture line generated by viscoelasticity of flexor muscle
Controlled passive extension method
· rubber bands removed
· controlled passive flexion commenced
· other hand used to flex finger
Postsplint
· 1st 2 weeks
· progressive active flexion and extension
· after
· unrestricted use
· continuing hand therapy until full ROM
Adhesions
· most common problem
· consider tenolysis after 3 months of intensive therapy
Joint contractures
· of PIP jt and DIP jt
Rupture
· urgent resuture
· prognosis guarded
· principles as above
Zone I
· if insufficient stump, pull-through technique
· core suture in proximal stump
· drill-holes through distal phalanx to nail
· sutures pulled through holes
· tied over button on nail
Zone III
· more easy to repair
· lumbricals not repaired
Zone IV
· uncommon
· leave portion of transverse carpal ligament intact
· prevent bowstringing
Zone V
· muscle division not sutured
· splinted with elbow and wrist flexed and forearm pronated
· to approximate muscle
· difficult to quantify
· tip to palm measurement
· inaccurate
· summation of MCP, PIP and DIP jt ROM
· does not reflect change as MCP flexion usually preserved
· Strickland formula
· (PIP + DIP flexion) - (PIP + DIP extensor lag)/175o x 100
· results excellent 75-100, good 50-75, fair 25-50, poor 0-25
· Chow has best results
· 98% good or excellent
· delayed primary repair
· rubber band splint
· sheath not repaired
Options
· most common is reconstruction by tendon grafting
· can sometimes perform FDS transfer
· esp. from ring finger to thumb FPL
Indications
· neglected FDP laceration
· one stage procedure if
· sheath well-preserved
· scarring minimal
· joints supple
· two-stage procedure if
· sheath scarred
· joint contracture
Disadvantages
· devascularised tendon segment used
· adhesions common
· two procedures usually required
Stage I
Procedure
· joint contractures released
· scarred portions of sheath and tendon excised
· A2 and A4 pulleys reconstructed
· silicone rod placed in prepared tendon bed
· sutured to distal FDP remnant
· proximal end left free in distal forearm
Complications
· infection
· rod migration
Postoperative
· passive ROM exercises
Stage 2
Timing
· when full passive ROM of joints
· usually after 2-4 months
Donors
· palmaris longus
· present in 85% on one side and 70% on both
· plantaris
· medial side of tendo calcaneus
· long extensor of 3rd toe
Procedure
· proximal and distal ends of rod exposed
· tendon graft sutured to distal end
· rod withdrawn proximally
· graft pulled into place
· distal end
· sutured to FDP stump
· usually secured to P3 with suture tied over dorsal button
· proximal end
· woven through proximal stump of FDP
· Pulvertaft technique
· leave immobilised for 3 weeks
· then proceed with active extension and passive assisted flexion
· most commonly seen in rheumatoid hand
· can occur anywhere
· otherwise trauma is most common cause
· occurs at insertion into P3
· most commonly involves ring finger
· longest in grasp
· swollen bruised finger
· inability to flex DIP jt
· may be bony avulsion fragment
· acute
· primary repair with dorsal tie-over suture
· chronic
· may not cause disability
· repaired with tendon graft
· loss of continuity of terminal slip at DIP jt
· flexion attitude of DIP jt
· may be hyperextension of PIP jt
· due to unopposed central slip tension at PIP jt
· secondary boutonniere deformity
Closed
· forced flexion of extended digit
· rupture of tendon
· avulsion of tendon with or without small fragment of bone
· forced hyperextension of DIP jt
· fracture of dorsal base of P3
Open
· laceration over dorsum of DIP jt
· most commonly involves ulnar fingers
Type 1
· closed trauma with or without small avulsion fracture
Type 2
· laceration at DIP jt
Type 3
· fracture of dorsal base of P3 with involvement of
· a) < 1/3 of joint surface
· b) > 1/3 of joint surface and volar subluxation of P3
Type 1
Splintage
· aluminium foam splint
· taped to dorsum of finger
· extending from tip to PIP jt
· DIP jt splinted in full extension (not hyperextension)
· left on for 6 weeks
· night splinting for further 2 weeks
· if unsuccessful, further periods of splintage of 2 weeks
K wire
· where external splint difficult to wear
· K-wire placed across distal joint to maintain full extension
Type 2
Suture
· wound extended
· H-shape
· wine-glass shape
· tendon repaired
· skin closed
· extension splint applied
· left on for 6 weeks
Type 3
Splintage
· for type 3a)
· treated as type 1
Repair
· for type 3b) with volar subluxation
· joint reduced
· fracture manipulated into position
· joint held in extension with longitudinal K-wire
· if fracture fragment not maintained
· pull-out suture over button on pulp
· splint for 6 weeks
· disruption of central slip at PIPjt
· subsequent volar migration of lateral bands
· results in
· loss of PIP jt extension
· DIP jt hyperextension
Closed
· forced flexion of PIP jt
· causes avulsion of central slip with or without bony fragment
· deformity usually not present at time of injury
· develops after 2-3 weeks
· develops as follows
· flexion of PIP jt due to loss of central slip and unopposed action of FDS
· stretching of expansion between central and lateral slips (transverse retinacular and triangular ligaments)
· lateral bands migrate volarward to position volar to axis of rotation
· pull of lateral bands exclusively directed to DIP jt which hyperextends
· MP jt also hyperextends because of pull of long extensor
Open
· laceration over central slip
· similar progressive deformity
Closed
· splint PIP in extension
· with Capener type splint
· leave DIP jt free
· gradually tighten splint until PIP jt in full extension
· exercise DIP jt
· active and passive flexion
· discard splint after 4-6 weeks
· when PIP jt fully passively extended and DIP jt can be fully passively flexed
Open
· operative repair of laceration
· central slip and lateral bands sutured with 5/0 Nylon
· if close to insertion, pull-out suture used
· PIP jt splinted in full extension for 6 weeks
· initially with aluminium splint
· replaced with Capener splint when wound healed and sutures removed
· laceration usually partial because of broad configuration of tendon
· tendon should be sutured
· PIP jt should be maintained in full extension for 6 weeks
Human bite
· penetrating contaminated injuries
· usually Staph and Strep with gram-negatives
· may be associated fracture or foreign body
· complications related to time before treatment
· treated aggressively
· antibiotics started immediately (Flucloxacillin, Gentamicin, Metronidazole)
· x-ray taken
· operative debridement
· wound extended
· culture taken
· debrided and irrigated
· left open
· dorsal slab with wrist 45o dorsiflexion and MCP jts 20o flexion
· wound inspection at 4-5 days
· tendon repaired
· wound closed if clean
· dynamic splinting when wound healed
Laceration
· repaired with Nylon
· hood must be repaired to keep tendon centralised over joint
· simple suture
· dynamic splinting after 3-5 days
· simple suture of tendons
· tendons may need to be retrieved as they retract at this level
· rents in retinaculum extended if required and then repaired
· some retinaculum can be excised if impedes tendon gliding
· used for lacerations at MCP jt and proximally
· much improved results cf. immobilisation
· thermoplastic splint
· dorsal splint with wrist held at 45o dorsiflexion
· outrigger device with slings to hold fingers extended at MCP and PIP jts
· palmar block to limit MCP flexion to 20o
· started at 3-5 days
· continued for 4 weeks