- See:
-
Excursion, of Tendons:
-
Thumb Deformities in Rheumatoid Arthritis:
-
Thumb Soft Tissue Defects:
-
Flexor Pollicis Longus:
-
Extensor Pollicis Longus
- Tendon Sheath Anatomy:
- A1 pulley: spans the MP joint, approximately 8 mm in width;
- note that the
FPB inserts just proximal to this pulley and the
adductor pollicis inserts
distal to the A1 pulley;
- oblique pulley: located over the mid aspect of the phalanx, approximately 10 mm in width;
- note that the
adductor pollicis partially inserts into the oblique pulley;
- A2 pulley located at the most distal aspect of the proximal phalanx, and is 9 mm in width;
- it may partially span the thumb IP joint;
- Zone 1 Flexor Tendon Injuries:
- in thumb, zone 1 extends from tip of finger to just distal to IP joint;
- contains, oblique and A2 pulleys;
- of these, the oblique is more important, but either can be sacrificed if the other remains intact;
- most tendon injuries of thumb occur at level of IP crease, which is near point of the
FPL insertion;
-
exposure:
- skin laceration needs to be extended both proximally and distally;
- flexor tendon sheath is "Z" step cut so that edge of the resected sheath lies about 1 cm beyond excursion of thickened area of sutured tendon;
-
tendon retrieval:
- first, note that FPL tendon lacerations often retract into the thenar area or wrist;
- unlike the fingers, the FPL often lacks a vinculum and does not have a lumbrical, and therefore the tendon is free to retract;
- when there is tendon retraction, the tendon must be retrieved at the wrist;
- second, note that the FPL tendon sheath is narrow in the thenar region, and therefore, passage of the tendon thru the sheath can be frustrating;
- it is important to avoid "scuffing" of the tendon edge as it is pulled thru the tunnel;
- pass a curved tendon grasper retrograde thru the FPL tendon, and insert a core grasping suture into the free edge of the tendon;
- the tendon grasper is then used to pull the suture back thru the tunnel;
-
delayed reconstruction:
FPL Advancement and Pull Thru:
- Zone 2 Flexor Tendon Injuries:
- over thenar eminence, injuries to
FPL tendon are likely to occur in conjunction
w/ injuries to thenar muscles &
recurrent branch of
median nerve;
- Tendon Transfers:
- the following musculotendinous units have adequate exursion (muscle amplitude), but lack tension strength based on cross sectional area:
EPL,
EIP,
PL;
- muscles that replace strength and excursion are the following
-
FDS to the long and ring fingers,
ECU, and
ECRL;
Restoration of flexor pollicis longus function by flexor digitorum superficialis transfer.
Flexor superficialis tendon transfers to the thumb: An alternative to the free tendon graft for treatment of chronic injuries within the digital sheath. J Hand Surg Am 1983;8:876-881.
