Aim: The purpose of this study was to compare patient outcome following THR after previous acetabular fracture versus replacement for idiopatic osteoarthritis. Methods: Patients with acetabular fractures that later required THR were matched by gender, age and year of THR to patients who received THRs for osteoarthritis. The patients function, complications, radiographic loosening and revision were documented. Results: 42 patients were in each of the 2 groups (62% male, mean age 51±11 years; mean follow-up was 6,1 (2–8) years. The average time from fracture to THR was 5,1 years, 28 patients were treated by ORIF and 14 non operativ. Patients with a previous acetabular fracture had lower WOMAC scores than arthritis patients, representing more pain and stiffness and worse function. There was no difference in the rate of acetabular component loosening (fracture group vs. arthritis group: 14,5% vs. 12,1%), femoral component loosening (7,0% vs. 9,4%), or acetabular (12,1% vs. 9,4%) or femoral (7,0% vs. 7,0%) revision. After adjusting for age, gender and length of follow-up, the time to revision was found to be shorter for the fracture group compared to the arthritis group (3,2± 4,0 vs. 5,9±3,7 years, p< 0,05). Conclusion: THR following previous acetabular fracture was associated with worse patient function than THR for osteoarthritis. Although loosening and revision rates were similar following THR in the two groups, revision total hip replacements occur earlier in patients with a previous acetabular fracture.