The invention relates to a shaft (1) of a hip joint prosthesis for implantation in the femur (5) of a patient, wherein the shaft (1) can be coupled with a ball head (2), which in turn can be inserted rotatably in the hemispherical recess of a socket insert (3). According to the invention, to avoid squeaking, it is proposed that the shaft (1) is formed asymmetrically in its outer and/or inner geometry and/or material composition.