Selective screw fixation is associated with early failure of primary acetabular components for aseptic loosening

Selective supplementation of acetabular component fixation with a screw during primary total hip arthroplasty (THA) assumes that the surgeon can detect when an acetabular component needs additional stability. In contrast, nonselective screw users do not alter their practice based on their interpretation of stability and either use screws all or none of the time. We aimed to determine the effect of selective screw use on aseptic acetabular component loosening. We retrospectively reviewed aseptic failures of acetabular components after primaty THA. We compared the survivorship of selective and nonselective supplementation of acetabular fixation with respect to time to revision, obesity, and screw use. Selective screw use (n = 16) was associated with earlier acetabular component aseptic loosening (median: 1.9 years; interquartile range [IQR]: 1.1-5.0) compared to nonselective screw use (n = 22; median: 5.6 years; IQR: 2.0-15.3; P = .010). Selective screw use was independently associated with earlier revision after adjusting for patient obesity. Obesity was associated with selective screw use in 50% of the cases vs 14% of nonselective cases (odds ratio: 6.3; confidence interval: 1.2-25.2; P = .028), possibly reflecting the increased difficulty in achieving acetabular component stability in this and other settings with compromised bone. Surgeons should carefully assess component stability at time of primary THA. If the acetabulum is not stable, the addition of screws alone may not be sufficient for acetabular component stability.