The FDP-FDS-FDP Dual Tendon Transfer: A Simple, Single-stage Reconstruction Technique for Chronic, Isolated Flexor Digitorum Profundus Tendon Injuries.

Abstract

The reconstruction of chronic flexor tendon injuries remains one of the more challenging injuries facing the hand and upper extremity surgeon. In the setting of an intact flexor digitorum superficialis (FDS), there are few indications for isolated flexor digitorum profundus (FDP) reconstruction. Because of the interplay of the FDP system, the reestablishment of normal tension of the FDP tendons and lumbricals is particularly challenging, and postoperative stiffness, quadriga, or lumbrical plus phenomena can actually lead to a deterioration of digital function with surgery. We present a technique for single-stage reconstruction of chronic FDP lacerations, particularly in the setting of "lumbrical plus" fingers. The key features of this technique are: the FDS is detached from the middle phalanx and advanced to the distal FDP stump; and the proximal stump of the FDP is advanced to reestablish proper lumbrical tension and sewn to the FDS tendon proximally. Postoperative therapy is according to standard, well-accepted flexor tendon rehabilitation protocols. This procedure avoids the need for tendon autograft harvest, and avoids the tensioning challenges of other FDP reconstruction techniques; it addresses the potential paradoxical extension with lumbrical tension by eliminating the retraction of the lumbrical and eliminates the potential for quadriga by separating FDP function from the adjacent digit. An illustrative case is presented.Level of Evidence: Level V.