Corail implants have shown to give good results in elective total hip replacements (THR) and in hemi-arthroplasties. Pre-operative planning to identify the correct size of the Corail implant is vital for good post-operative outcomes. An undersized implant can lead to subsidence. The aim of the study was to review the incidence of subsidence. Post-operative radiographs of trauma patients (n=39) and elective (n=45) patients who had Corail femoral implants were reviewed. The implant-to-canal (I:C) ratio were calculated at the given 50% and 70% levels of the Corail implant. Follow up radiographs were reviewed to identify subsidence. The average age of patients was 80.3 years (range 66–93 years) in hemi-arthroplasties and 61 years (range 18–88) in elective THRs. The implant to canal (I:C) ratio at the 50% and 70% levels in trauma patients were 0.77 (range 0.54 – 0.97) and 0.81 (range 0.59 – 0.94) respectively. In elective patients, the ratios at the 50% and 70% marks were 0.77 (range 0.57 – 0.98) and 0.81 (0.56 – 0.95). One case of subsidence was seen in a collarless implant and I:C ratios at 50% and 70% were 0.57 and 0.56. A larger study is required to determine the reliability of this novel ‘implant:canal’ ratio to predict incidence.