Radiographic Assessment of Outer Head Migration after Bipolar Arthroplasty

Radiographic assessment was done to investigate outer head migration after bipolar arthroplasty in 44 osteoarthritic hips (35 patients). Bone graft was performed on the lateral edge of the acetabulum using resected femoral heads in 19 cases who had dysplastic acetabulae.There was a significant correlation at six months between CE angle and medial migration (r=-0.43, p 6mm) is significantly greater than that in the shallower reaming group (<5mm).Thickness of the grafted bone correlated strongly with superior migration at 12 months (r=0.93, coefficient for slope=0.85). This result shows that the grafted bone did not act as a brake on the superior migration of the outer head.