A support apparatus for supporting an end of a distraction marrow nail includes a base plate attachable to the pelvis, and a mounting device on the base plate for mounting of the support end of the distraction marrow nail. The mounting device includes a ball seat having a cavity forming a ball seat surface for mounting a ball on the support end of the distraction marrow nail, wherein the inside radius of the ball seat surface corresponds to the outside radius of the ball, and wherein the ball seat is arranged so that the ball of the distraction marrow nail can be movably mounted such that the distraction marrow nail can perform a movement sufficient for an extensively normal movement pattern of a femur and cannot luxate out of the ball seat when implanted in the femur.
