Resection of the flexor digitorum superficialis reduces gliding resistance after zone II flexor digitorum profundus repair in vitro

The effect of complete or partial resection of the flexor digitorum superficialis (FDS) tendon on the gliding resistance of the flexor digitorum profundus (FDP) tendon after FDP tendon repair was investigated. Twenty-four human FDP tendons were cut to 80% of their transverse section and repaired with a modified Kessler or a Massachusetts General Hospital augmented Becker suture technique. Gliding resistance was measured with the following constructs: intact state, sutured FDP tendon with FDS tendon intact, sutured tendon without FDS tendon, and sutured tendon with one slip of FDS tendon excised. After FDP repair the gliding resistance after modified Kessler repair increased 247% with FDS intact, 132% with one slip of FDS present, and 103% with FDS entirely removed. With a Becker repair, resistance increased 671% compared with normal with the FDS intact, 379% with one slip of the FDS, and 348% without the FDS tendon. Preserving the whole FDS resulted in a significantly larger increase in gliding resistance after FDP repair than did full or partial FDS removal, which were not significantly different from each other. These results suggest that the FDS tendon affects the gliding resistance under the pulley after FDP repair and that partial FDS excision may facilitate gliding of a bulky FDP repair.