Week 12 - Extensor Tendon Injuries Flashcards
why are extensor tendons vulnerable to injury?
little subcutaneous tissue on dorsal hand
name 3 common post injury complications of extensor tendon injuries.
- tendon adhesions
- extensor lag
- significant stiffness
what do extensor tendons have instead of a synovial sheath?
paratenon
name 4 characteristics of extensor tendon anatomy.
- numerous soft tissue attachments and interconnections
- no synovial sheath but a paratenon
- extra-synovial course facilitates repair
- thinner and tend to become adherent to underlying bone
the anatomical characteristics of extensor tendon prevent what?
retraction of divided tendon
what do the characteristics of extensor tendons allow for?
conservative management
describe extensor lag.
- good PIP passive extension but extensor tendon can’t fully extend actively
- don’t have full active extension ROM
affects AROM but could still have good PROM
tendon adhesions
- circulates around tendon and provides synovial fluid
- thinner than a sheath
paratenon
name the extensor tendons of the first dorsal compartment.
- abductor pollicis longus
- extensor pollicis brevis
name the extensor tendons of the second dorsal compartment.
- extensor carpi radialis longus
- extensor carpi radialis brevis
name the extensor tendon of the 3rd dorsal compartment.
extensor pollicis longus
name the extensor tendons of the 4th dorsal compartment.
- extensor digitorum communis
- extensor indicis proprius
name the extensor tendon of the 5th dorsal compartment.
extensor digiti minimi
name the extensor tendon of the 6th dorsal compartment.
extensor carpi ulnaris
where is juncturae tendini located?*
proximal to MCP joint
what does juncturae tendini bind to?*
extensor digitorum communis
- proximal to MCP joint
- binds EDC
juncturae tendini
broad fibrous band with fibers from sagittal bands
dorsal hood - MCP joint
what is the purpose of the dorsal hood?
to center EDC
innervation of EDC?
radial nerve
name the three parts of EDC (each digit)
- central slip
- 2 lateral slips
- proximal to lateral bands
- unite distally to form terminal tendon
lateral slips
name the functions of the volar and dorsal interossei.
- flexion of MCP
- contribute to PIP extension when MCP is flexed
which tendon do the lumbricals rise from?
FDP
where do the lumbricals insert?
into extensor tendon - radial lateral band of each finger
where are the central and lateral slips located (in general)?
on outside of joint to keep everything in
critical for positioning and holding in the right place and observing for deformities
retinacular ligaments
stabilizes extensor tendon over PIP joint
transverse retinacular ligament
name the 3 retinacular ligaments.
- transverse
- oblique
- triangular
helps to center tendon on dorsal surface
oblique retinacular ligament
where is the oblique retinacular ligament located?
volar to axis of PIP joint and dorsal to DIP joint
prevents volar subluxation of lateral bands
triangular ligament
what are odd # zones of injury for extensor tendons?
over joints
what are even # zones of injury in extensor tendons?
-phalanxes, metacarpals, forearm
injury is distal to the DIP joint
zone I
injury is overlying the middle phalanx
zone II
injury is over the PIP joint
zone III
injury is overlying the proximal phalanx
zone IV
injury is over the MCP joint
zone V
injury is over the metacarpal
zone VI
what is the most common zone of extensor tendon injury?
zone VI
injury to the tendon and retinaculum over the wrist joint
zone VII
injury to the muscle belly in the distal forearm
zone VIII
injury is distal to the IP joint of the thumb
zone TI
injury is overlying the proximal phalanx of the thumb
zone TII
injury is over the MCP joint of the thumb
zone TIII
injury is over the CMC joint of the thumb
zone TIV
zone I - ET
DIP joint
zone II - ET
middle phalanx
zone III - ET
PIP joint
zone IV - ET
proximal phalanx
zone V - ET
MCP joint
zone VI - ET
metacarpals
zone VII - ET
carpals
zone VIII - ET
proximal wrist
which zone is mallet finger in?
zone I
describe an orthosis for a mallet finger.
- must be able to flex and extend PIPs
- maintains 10-15 degrees of DIP hyperextension
- allows PIP movement
name the 3 rehab approaches for extensor tendon injuries.
- immobilization (no movement)
- early but controlled mobilization (some movement) - short arc of motion
- early and active mobilization (full movement)
disruption of the terminal extensor tendon secondary to laceration, rupture, avulsion
mallet finger
what is the mechanism of mallet finger injury?
hyper flexion of DIP joint
what is the resulting deformity of mallet finger?
inability to extend DIP joint
how many weeks of immobilization does mallet finger require?
6-8 weeks
what can a mallet finger orthosis not allow?
cannot allow even slight flexion at DIP
for a mallet finger (closed injury) pt. must support finger tip at all times during splint ___ & ___.
removal and replacement
what type of exercise should begin during weeks 1-6 or 8 for a mallet finger (closed) injury?
active PIP flexion/extension in orthosis
n/a
n/a
what zone(s) is involved in a boutonniere injury?
zones III and IV
what is the resultant deformity of boutonniere injury?
PIP flexion with DIP extension
- results from either an open or closed zone III extensor tendon injury.
- resultant deformity is PIP flexion with DIP extension
boutonniere injury
name 4 causes of boutonniere injury.
- lacerating, rupture of central extensor tendon
- proximal phalanx head button holes through tendon
- volar migration of the lateral bands
- hyper-extension of DIP joint
describe the mechanism of injury of boutonniere deformity.
disruption of central slip and triangular ligament
name 6 causes of injury of boutonniere deformity.
- rupture
- avulsion
- burns
- laceration
- RA
- PIP joint dislocations
in order to be classified as boutonniere deformity - which 2 deformities must be present?
PIP flexion AND DIP extension
name the 3 components of boutonniere deformity injury.
- central slip rupture
- triangular ligament attenuation
- lateral band volar migration
- very complex injuries involving soft tissue, PIP joint and/or DIP joints
- adhesion of either central slip and/or lateral bands causes limitation in BOTH flexion and extension
- if untreated, deformity becomes fixed
boutonniere injury
describe orthotic treatment for boutonniere deformity.
- static orthotic treatment
- PIP in full extension, DIP is free
how long is a splint for boutonniere deformity worn for?
6 weeks
describe splinting for boutonniere deformity during weeks 6-9.
- may need dynamic extension but allow active flexion
- continue night time static splinting
describe exercise during weeks 1-3 for boutonniere deformity.
DIP blocking - 10 reps, 5 times/day
describe exercise during weeks 3-6 for boutonniere deformity.
- flexion - GENTLE flexion to 30 degrees
- extension - active PIP extension with MCP in neutral
- continue night time static splinting
describe exercise during week 7 for boutonniere deformity.
begin PROM, watch for extensor lag
describe exercise during weeks 10-12 for boutonniere deformity.
start gentle strengthening
develops from either loss of extension mechanism at the distal phalanx or tightening or overpull of the extensor mechanism on the proximal phalanx.
swan neck deformity
name 3 causes of injury to the terminal tendon that leads to swan neck deformity.
- laceration
- closed avulsion from direct blow on the distal phalanx of an extended digit
- attrition by weakening from chronic inflammation of the DIP joint along with tendon subluxation due to RA or other inflammatory process.
hyperextension of the PIP joint can be due to the tightness of the intrinsic muscles and increased pull at the central slip. could be secondary to RA, spasticity from TBI, or stroke and intrinsic tightness alone
swan neck deformity
laxity of what is also a cause of swan neck deformity and the hyperextension seen at the PIP joint?
volar plate
which zone of injury is swan neck deformity?
zone III but cause usually elsewhere (DIP, PIP or MCP joints)
describe the deformities of swan neck deformity.
- PIP hyperextension with DIP flexion
- MCP flexion can occur too
name 2 causes of swan neck deformity.
- usually at MCP joint (RA)
- untreated mallet finger
name the 2 features (deformities) of swan neck deformity.
PIP hyperextension and DIP flexion
extensor tendon rises above PIP joint
swan neck deformity
describe the role of the ring splint.
prevents full extension of PIP, holds it in slight flexion
describe an orthosis for zone IV injury.
- hand based splint, involved finger in extension
- MCP 0-30 flexion, PIP full extension
describe the orthotic timeline for zone IV injury.
- splint 4-6 weeks, 24 hours/day
- continue splint for 10 weeks after injury (night time)
what does an orthosis for zone IV look like?
safe position
- applied for extensor tendons repair management
- pt. can actively flex his digits while the metallic springs retrieve the extension position passively
Levame system
what does short arc of motion promote?
passive extension
- usually uncomplicated rehab if started early
- responds well due to mobility of dorsal skin
- not the complicated inter-dependence as seen in fingers
zone V & VI (dorsum of hand)
describe an immobilization orthosis for zone V and VI injuries.
- use resting hand splint pattern omit thumb
- MCP in 10-20 degrees flexion, IPs full extension
describe a dynamic orthosis for zone V & VI injury.
dorsal outrigger and flexion block
- wrist 40-50 degrees extension
- allow 30 degree of active flexion at MCP joint to volar block splint
- keep IPs in extension
describe a dynamic orthosis at 3-4 weeks for zone V & VI injury.
- flexion block is discontinued
- dynamic extension continues
describe a dynamic orthosis at weeks 4-6 for zone V & VI injury.
MCP block splint is worn until weeks 7-8
describe key aspects of rehab for zones V, VI, VII, and VIII injury.
- wrist extension is key to balanced hand function
- importance of MCP joint extension
describe an early orthosis for zones V, VI, VII, and VIII injury.
wrist - 30 degrees extension
MCPs - slight flexion
PIPs, DIPs - extension at night, out of splint during day
what should you do if you suspect a wound is infected?
smell it and call doctor
vacuum to lift skin up
snake biting kit
early controlled mobilization results in what?
better range of motion at the end of 6 weeks
grip strength comes back faster and stronger with ___ ___ compared with ____.
controlled mobilization, immobilization
goes over middle and ring fingers and under index and small fingers
relative motion orthosis
what is a relative motion orthosis used for?
used for tendon balance - balances out the finger
static progressive splints can’t have what?
elastic strings - fishing wire is used instead
which zones are involved in mallet finger?
I and II
which zones are involved in boutonniere deformity?
III and IV
describe general treatment methods for injury to zone I or II.
likely won’t require surgical intervention and will be referred to therapy or the surgeon will simply immobilize the DIP in extension for 6 to 8 weeks.
describe general treatment methods for injury to zone III or IV.
can be treated conservatively or through surgery depending on the extent of the tendon damage
describe general treatment methods for injury to zones V, VI, or VII.
will require surgical repair followed by immobilization or controlled early motion protocols.
in mallet finger injuries, flexion activities must be balanced with active extension to ensure that there is no recurrence of what?
DIP extensor lag
describe splinting for boutonniere deformity.
-splint PIP in full extension for 6 weeks, and promote DIP active and passive flexion to prevent stiffness of the oblique retinacular ligament.
watch closely for __ ___ ___ in boutonniere injury when pt. is medically cleared to begin active exercises.
PIP extensor lag
injury in zones V and VI are typically treated with which 2 protocols?
- immobilization
- controlled early motion
