Bipolar hip arthoroplasty for hip destruction due to rheumatoid arthritis was performed on 16 joints in 10 cases. Bone grafting was performed on 8 joints. The clinical results and roentgenographical progress in migration or sinking of the prosthesis were followed for 10 to 48 months.
At the time of follow-up, walking ability was increased in 8 cases and not changed in 2 cases. Progression of central migration of the outer head was seen in 6. Subsidence of the femoral stem was noted in 4. Migration of the outer head had generally stopped within 6 months, but progressed over one year in some cases. The ways of obtaining firm bone grafting and the suitable timing for weight bearing must be further studied.
