The management of femoral bone loss is challenging during revision hip arthroplasty. In patients with Paprosky grade IIIB and IV defects, obtaining fixation and rotational stability using traditional surgical constructs is difficult. The use of a custom-made internal proximal femoral replacement prostheses has been proposed as a solution in patients, with severe femoral bone stock loss. However, there is a paucity in the literature on their use and long-term outcomes. We report on the clinical and radiological results of our cohort. We retrospectively reviewed all patients who underwent internal proximal femoral replacement for revision hip arthroplasty between April 1996 and April 2019. All patients had at least 2 years of follow-up time. 160 patients underwent limb salvage at our institution using internal proximal femoral replacement. The mean follow-up was 79.7 months (S.D 41.3). Indications for revision included periprosthetic fractures, aseptic loosening, and deep infection. The mean Oxford hip score increased from 13.8 (0–22) to 31.5 (18–43) (paired t-test, p < 0.001). Kaplan-Meier prosthesis survival analysis with revision as the endpoint was 87% at 5 years. None required revision of the femoral stem. There were four dislocations (5%) and there was failure to eradicate the deep infection in four. This technique allows instant distal fixation, allowing for early mobilisation. Long-term clinical and radiological outcomes are encouraging and the complication rates are acceptable for this patient group.