The indications for total hip arthroplasty (THA) after failed internal fixation of a proximal femur fracture vary. Published studies on this topic are broad-ranging and do not distinguish between intracapsular and extracapsular fractures. This led us to conduct a retrospective analysis comparing the clinical outcomes, radiological outcomes, technical problems and complications between these two types of fractures. The functional outcomes of THA after an extracapsular fracture will be worse than the ones after an intracapsular fracture. This was a retrospective, single-center study of 59 THA cases performed after internal fixation of a proximal femur fracture. These procedures were performed between 2002 and 2013 in 58 patients (22 men, 36 women). There were 40 intracapsular fractures and 19 extracapsular fractures. The initial fracture fixation involved a screw-plate (n=50), intramedullary nail (n=6) or screws (n=3). The mean patient age at the time of THA was 67 years [22-94]. The THA was performed an average of 2.8 years [0.2-28] after the fracture. The posterolateral approach was used in 55 cases (93%). Ten patients (17%) had the fixation hardware removed before the THA procedure, on average at 30 months [1-240] after the fracture. During the THA procedure, a cemented stem was used in 31 cases (53%) and a cementless stem in 28 cases (47%). A cementless press-fit cup was used in 56 cases (95%), of which 35 were dual mobility cups (60%), and a cemented cup was used in the other 3 cases (5%). All patients were reviewed by a physician not involved in the surgical procedures who performed a clinical and radiological examination. No patients were lost to follow-up; two patients died. Ten patients suffered an intraoperative femur fracture (17%) and four suffered a dislocation (2 early, 2 late) (6.8%). Nine hips had to be reoperated (15%), of which five required an implant change (8.5%). There were significantly more intraoperative fractures and postoperative complications in the THA cases after extracapsular fracture. With a mean follow-up of 38 months [12-149], the mean PMA and Harris scores were 14.6 [3-18] and 74 [10-100], respectively; these scores were significantly lower in the THA cases after extracapsular fracture (p<0.05). With an endpoint of revision with implant change, the overall 40-month survival was 94% (95% CI: 0.25-0.55); it was 97% (95% CI: 0.62-0.85) for the intracapsular fracture cases and 84% (95% CI: 0.39-0.75) for the extracapsular fracture cases (p<0.05). Secondary THA after failed fixation of proximal femur fractures has more complications than primary THA. Subgroup analysis identified more technical problems in the THA cases after extracapsular fracture and a higher number of complications, particularly dislocation and periprosthetic fractures. IV - Retrospective study.