Acetabular lucent lines and mechanical stress in total hip arthroplasty

The radiographs of 97 patients (117 hips) who had a straight-stem Muller femoral component and a non-metal-backed acetabular component were reviewed to determine whether the mode of acetabular loosening predicted by finite element stress analysis (FESA) is observed clinically. The follow-up period averaged 3.1 years (range, 2.0-4.6 years). Significantly more lucent lines were present in zones 1 and 3, compared with zone 2 (P less than .01). This finding corroborates the predictions of FESA and suggests that the production of acetabular lucent lines is due in part to chronic mechanical overload.