Cementless total hip replacement: past, present, and future.

Cementless total hip replacement (THR) is rapidly being accepted as the surgery for arthritic diseases of the hip joint. The bone-ingrowth rate in porous-type cementless implants was about 90% over 10 years after surgery, showing that biological fixation of cementless THR was well maintained on both the stem and cup sides. As for the stress shielding of the femur operated using a distal fixation-type stem, severe bone resorption was observed.

Insufficiency fracture in the medial wall of the acetabulum after total hip arthroplasty.

Insufficiency fracture following total hip arthroplasty (THA) frequently occurs in the superior and inferior pubic ramus, the puboischial rami, or the ischium around the obturator foramen, while it rarely occurs in the medial wall of the acetabulum. Here, we report three cases showing insufficiency fracture in the medial wall of the acetabulum following THA. In our three cases, two fractures resulted from the development of bone fragility due to osteolysis at the prosthesis site, and the convergence of mechanical stress on the acetabular load bearing point due to loosening of the cup.