The current invention concerns a nail device 1, 2 for repairing bone defects 26, suitable to be attached to two main bone fragments 3, 4 and extending over a bone defect 26 located between said bone fragments 3, 4, whereby the length of the device 1, 2 between the main bone fragments 3, 4 is able to increase and/or decrease in a hydraulic way, so that new bone tissue in the caused openings can be formed, the nail device 1, 2 comprising: ‒ a proximal end part 5 comprising one or more proximal locking holes 6 and a hydraulically activatable actuator 22 ‒ a distal end part 7 provided with an axially extendable nail 8, said nail 8 comprising distal locking holes 9 ‒ a housing 10 extending between said proximal end part 5 and said distal end part 7, said housing 10 comprising an internal bore 11 in which the nail 8 is centrally and axially extendable provided and ‒ a fluid supply assembly for the supply of hydraulic fluid which is connectable with said proximal end part (5), wherein said proximal end part (5) comprises a radially oriented socket (33) which is arranged for the mechanically detachable and reversible engagement of said fluid supply assembly. In another aspect, the invention relates to a targeting jig 35 for the installation of a nail device 1, 2 for repairing bone defects. In still another aspect, the invention relates to a kit for the installation of a nail device 1, 2 for repairing bone defects. The invention further concerns a method for installation of a nail device and a method for adjusting a nail device.La présente invention concerne un dispositif denclouage (1, 2) destiné à la réparation de défauts osseux (26), apte à être fixé à deux fragments osseux principaux (3, 4) et sétendant sur un défaut osseux (26) situé entre lesdits fragments osseux (3, 4), grâce auquel la longueur du dispositif (1, 2) entre les fragments osseux principaux (3, 4) peut augmenter et/ou diminuer de manière hydraulique, de sorte quun nouveau tissu osseux dans les ouvertures p
