Chapter 30 - Flexor and Extensor Tendon Injuries Flashcards
predominant collagen in tendon?
Type I collagen
Phases of tendon healing: inflammatory phase
injury to 7days
infiltration of fibroblasts and macrophages
repair strength relies ENTIRELY on suture
Proliferative phase of tendon healing
second phase 7-21 days
neovascularization occurring
fibroblasts deposit T III collagen (immature) - later gets replaced by type I
remodeling phase of tendon healing
weeks 3-12
collagen fibers become reorganized along the length of the tendon
mechanisms of tendon healing: extrinsic tendon healing
inflammatory cells and fibroblasts derived from tendon sheath
predominates when repair is immobilized
collagen deposition is disorganized
mechanisms of tendon healing: intrinsic tendon healing
inflammatory cells and fibroblasts derived from within tendon and epitenon
predominates if motion rehab used post op
diagnosing an FDS injury
inability to flex the PIP joint with the adjacent digits held in extension
Zone III extensor tendon injuries indicate disruption of what structure?
central slip of the common extensor
positive elson test - inability to actively extend the PIP joint with the joint resting in 90degrees of flexion, or the DIP extends with attempted PIP extension
Zone V extensor tendon injuries indicate disruption of what structure(s)
sagittal bands
loss of active mcp extension ans extensor tendon subluxation into valleys between mcp joints with MCP flexion
What tendon lies ulnar - EDC or EIP?
EIP
what tendon lies ulnar - EDM or EDC?
EDM
What mm belly is the most distal in the fourth dorsal extensor compartment?
EIP
when to repair a partial flexor tendon laceration
when more than 60% of the tendon is disrupted
strength of a repair is directly proportional to what?
the number of core sutures in the repair (3-0 or 4-0 core suture usually)
minimum number of core sutures required to allow active motion immediately post op?
4
Jersey finger
Zone one flexor tendon injury - either avulsion of the FDP off the volar lip of the distal phalanx, or a fracture of the volar lip of the distal phalanx base
Type I jersey finger
FDP retracted to palm - vincula are disrupted
recommend acute repair (<7-10 days post injury)
Type II jersey finger
FDP to level of PIP (vincula intact)
repair within several weeks
Type III jersey finger
attached to large avulsion fragment
passive motion protocols for flexor tendon repair
kleinert - wrist at 45 flexion, rubber bands to the nails - actively extend fingers then rubber bands pull down slowly
duran - wrist at 20 degrees flexion - patient passively extends the DIP and PIP joints
early active motion protocols
use dorsal blocking splint limiting wrist etension to neutral or slight flexion
moderate force and potentially high excursion
synergistic motion regimen
low force, high tendon excursion
passive digit flexion with active wrist extension followed by active digit extension coupled with active wrist flexion
compared with passive motio regimen, active motion - less flexion contracture, increased joint motion, equivalent re-rupture rates
when does repair re-rupture happen most frequently?
post op day 7-10
zone I extensor tendon injury - mallet finger
forced hyperflexion of an extended dip
treat with full time extension splinting of DIP for 6-8 weeks
Zone II extensor tendon injury (acute boutonniere deformity)
acute loss of PIP extension 2/2 central slip injury
mechanism: palmar dislocation of the pip joint
subsequent volar subluxation of the lateral bands causes DIP extension
TX; PIP extension splinting with DIP free
lumbrical plus deformity
paradoxical extension of the IP joint of the injured digit with attempted flexion
caused by overlengthening of the fdp distal to lumbrical tendon - causes force of FDP to be transmitted to lumbrical (insertion on radial lateral band) rather than flexor
