Fractional Lengthening

Indications

Spastic, flexed fingers with inadequate finger extension and the inability to release objects. This spasticity is usually associated with cerebral palsy or traumatic brain injury.

Technique

Longitudinal incision (6–8 cm) over distal third of forearm just ulnar to palmaris longus tendon (Fig. 59-1). Bluntly dissect through subcutaneous incision to identify flexor tendons and neurovascular bundles. Identify flexor digitorum superficialis (FDS) tendons palmar to median nerve.
Isolate each FDS tendon proximal at its muscle-tendon junction. Incise tendinous portion within the muscle-tendon junction, such that intact muscle remains on both sides of the cut tendon (Fig. 59-2A,B). Gently extend finger to separate cut ends of FDS tendons ~1 to 1.5 cm.
Isolate flexor digitorum profundus (FDP) tendons deep to median nerve. Long, ring, and small fingers always have common muscle belly and can be fractionally lengthened together at muscle–tendon junction (Fig. 59-3). Index FDP tendon often has a separate muscle–tendon belly and requires individual lengthening.
Incise tendinous portion of FDP tendons within the muscle–tendon junction, such that intact muscle remains on both sides of the cut tendon (Fig. 59-4). Gently extend finger to separate cut ends of FDP tendons ~1 to 1.5 cm.
Perform concomitant wrist flexor tendon lengthening, tendon transfer, or fusion as indicated.
Close subcutaneous tissue and skin with absorbable suture.