In flexor tendon graft repair, graft is taken from

Secondary repair and reconstruction of flexor tendonsIf flexor tendons cannot be repaired within the first 10 to 14 days (delayed primary repair), the repair is considered to be secondary repairDonor tendons for grafting, in order of preference, are the Palmaris longus, the plantaris, and the long extensors of the toes. In rare cases, the index extensor digitorum communis, the extensor indicis proprius, and the flexor digitorum sublime are used.(Refer: Mohindra's Fundamentals of Ohopedics, 2nd edition, pg no. 497)