Fig. 1

a Plain X-ray of the implanted femoral components taken immediately after surgery. The implant (PROFEMUR® Z) fitted at the metaphyseal-diaphyseal junction and the proximal diaphysis. The vertical distance between the lateral shoulder of the prosthesis and the superior tip of the greater trochanter on the radiograph was recorded as A; the distance from the lateral shoulder of the prosthesis to the distal tip of the prosthesis was recorded as B. b Plain X-ray of the implanted femoral components taken on follow-up. When measuring subsidence, corrections were made using the ratio of vertical distance between the lateral shoulder of the prosthesis to the distal tip of the prosthesis (B’/B). The corrected vertical distance between the lateral shoulder of the prosthesis and the superior tip of the greater trochanter was calculated using the equation: A X (B’/B). The subsidence was calculated as A’ – A X (B’/B)