- Discussion:
- it is essenital to accurately determine the optimal tension to be applied to the motor unit;
- use the relaxed natural cascade of the fingers to assist in determining the optimal tension;
- most often the tendon graft is sutured to the proximal FDP in the mid palm, distal to the origin of the lumbrical;
- consider using a Pulvertaft weave to join the tendons; (see tendon repair)
- have fine misquito hemostat ready for this stage;
- Technique:
- apply traction and test excursion and motion of IP joints are tested;
- mid-palmar anastomosis:
- indicated when the palm is free of substantial injury and scar and the proximal end of the profundus tendon remains in the palm;
- advantages: palmaris longus is usually long enough (no need to additional graft harvest);
- proximal tenorrhaphy is performed in the palm with a Pulvertaft weave technique with 4-0 Mersilene, keeping the lumbrical muscle free of the tenorrhaphy;
- end to end or "button hole" suture is performed in palm proximal to origin of the lumbricals;
- if proximal graft is placed distal to the origin of the lumbricals and if graft is placed slightly loose, the finger may develop a lumbrical plus deformity (where as overtightening can cause quadriga);
- tendon graft is then sutured to the muscle belly, w/ muscle belly at half resting length & w/ wrist in neutral position;
- alternatively, avoid the occurance of a lumbrical plus finger by dividing the lumbrical either in the palm or more distally at the radial band;
- proximal (forearm) anastomosis:
- indicated when the palm is heavily scarred and/or the proximal end of the profundus tendon is retracted proximal to the palm;
- disadvantages:
- typically the palmaris longus is not long enough and surgeon may have to use plantaris or toe extensor for extra length;
- Complications:
- tendon shortening:
- in primary repair, musculotendinous unit can compensate for shortening as much as 1 cm;
- excissive tendon lengthening:
- a common complication is to leave the tendon too long;
- this produces a lumbrical plus finger;
- lumbrical plus finger can also be seen in unrepaired lacerations of flexor profundus and amputation of the distal phalanx;
- this is manifested by intrinsic plus attitude in involved finger on attempted flexion w/ MP flexion there will be IP extension (Paradoxical Extension);
- if several weeks have passed before this condition is noted, the radial lateral band may become adherent to the adjacent tissues;
- in this case, revision of the tendon repair will not correct the adherence of the lateral band;
- the adherent lateral band must be released in order to restore PIP flexion
Staged flexor tendon reconstruction fingertip to palm.