A prosthetic hip-joint includes: a. a prosthetic acetabulum cup for implantation into a pelvis; b. a prosthetic femoral assembly which includes: i. a ball-shaped femoral head that during implantation becomes located within the cup; and ii. a femoral stem that is fixed at a first end to the head, and that has a second end distal from the first end which is adapted for implant into a medullary canal of a femur, and c. a liner assembly adapted to he secured to the cup and is also adapted to receive and to constrain the head against dislocation. In one aspect the hip-joint permits the head to rotate through an angle which exceeds at least 153 degrees while concurrently constraining the head against dislocation. In another aspect the hip joint constrains the head a dislocation by a preestablished amount of force which is adjustable during implantation thereof.