PMC

The Kaplan-Meier survivorship plot with 95% confidence intervals shows 97.8% survivorship with revision for any reason as the end point.

An AP radiograph of the only patient with wear greater than 0.06 mm per year and cup inclination of 72° is shown.

Median penetration rates were compared with the mean and the difference ranges from 0.001 mm at 3 years to 0.01 mm at 5 years.

The linear head penetration values at various followups are plotted here. The polyethylene wear rate is represented by the slope of the best-fit linear regression line. For our study, the wear rate is 0.015 mm per year.

The Martell method of linear wear measurement is shown in this radiograph. The circles that best fit the femoral head and acetabular cup are detected by the software. The direction of the head penetration is automatically calculated as shown.

The femoral head penetration rates per year at (A) 3 years and (B) 4 years versus acetabular cup inclination are shown. No significant difference was observed (p = 0.150) for components in or outside the 40° to 50° cup inclination range.