The linear wear measurement of inner articulation for bipolar hemiarthroplasty (BHA) was performed on 28 hips by using the changed radiographic condition. There were two types of innerheads; 22mm (15 hips) and 28mm (13 hips).
The average annual linear wear rate was 0.07mm/y in the 22mm head, and 0.04mm/y in the 28mm head. The wear rate of the inner articulation in BHA was less than that of THA.
Osteolysis was observed in 7 hips in the 22mm head group (46%). There was no significant difference in the linear wear regardless of whether osteolysis was present.
