We have treated the hip joints with osteoarthrosis (OA) and reumatoid arthritis (RA) by bipolar arthroplasty (OMNIFIT UHR), adding the acetabular bone grafts in cases of severe bone defects. Migrations of implants were survayed roentgenographically. Of 17 coxarthroses, 4 hips were grafted bone using resected femoral head to the lateral side of the acetabulum, and of 16 hips with reumatoid arthritis, 8 hips were grafted the ilium or resected head to the acetabulum. In OA cases without bone graft, some outer heads of artificial joints have migrated both to the center and superior, and only superior migration was noted in RA cases. On the other hand, almost all outer heads of bone grafted cases have migrated from the result of collapse in the grafted bone. Sinking of stems was noticed slightly.
In conclusion, it is necessary to graft solid bone and avoid full weight bearing of the hips for at least six months for the prevention of bone collapse.
