Polyethylene wear in Scanhip arthroplasty with a 22 or 32 mm head: 62 matched patients followed for 7-9 years.

We measured radiographic polyethylene wear in patients with Scanhip arthroplasty and no clinical or radiographic signs of loosening. The patients were divided into 2 groups according to head sizes. 32 patients (33 hips) had an implant with a 22 mm and 30 patients (34 hips) with a 32 mm head. They were followed for 7-9 years. The groups were matched for diagnosis, sex, weight, age, and time of follow-up. The mean linear wear with a 22 mm head was 1.1 mm and with a 32 mm head 1.5 mm (p 0.004), which corresponds to a yearly wear rate of 0.15 mm and 0.18 mm, respectively. The mean difference in volumetric wear was greater, 420 mm3, as compared to 1239 mm3.