Transferring the flexor superficialis tendon: technical considerations in the prevention of proximal interphalangeal joint disability.

Transfer of the flexor digitorum superficialis tendon to restore functional loss may result in a flexion contracture or hyperextension deformity of the proximal interphalangeal joint of the donor finger. Removal of the flexor tendon through the membranous interval in the fibro-osseous sheath between the annular pulley (A2) and the proximal collar (A1) avoids scarring of the structures volar to the proximal interphalangeal joint. Sixteen flexor superficialis tendons were removed at this membranous interval for transfer. No functional impairment from flexion contracture or hyperextension deformity developed after operation in the donor fingers, although an average 8 degrees of loss of extension was noted at the proximal interphalangeal joint in 50% of the donor fingers.