An assembly for use in repairing a severed tendon comprises an elongate threading element adapted to transit along a lumen of a tendon sheath, for covering a curved needle and carrying the needle within the lumen. The assembly can also comprise a liner for lining an internal surface of the tendon sheath, defining an internal passage along which a tendon stump coupled to the curved needle can pass. The liner can have a collapsed, rest configuration in which it is adapted to be inserted into the lumen of the tendon sheath, and an expanded, operating configuration, the liner being movable to the expanded configuration by contact with the tendon stump. Once released from the liner, the threading element receives the curved needle, for covering and carrying the curved needle through the liner and along the lumen of the tendon sheath trailing the connected tendon stump.