New surgical instruments and methods used to implant elements of a reverse hip prosthesis in a patient are described. The instruments are impactors which are struck with a hammer at their proximal ends after the instrument has been used to position the implant element in the patient. An acetabular cup impactor has inclination and anteversion rods which are used to position the acetabular cup optimally in the acetabulum. An acetabular ball impactor affixes the acetabular ball in the acetabular cup by means of a Morse taper. And a femoral cup impactor affixes the femoral cup in the femoral stem by means of a Morse taper.