The effectiveness of the proximal femoral stem centraliser on the stem alignment in total hip replacement

We studied a new polymethylmethacrylate proximal femoral centraliser designed for use along with the distal femoral centraliser. Using cadaver femora we conducted an in vitro study to measure the influence of the proximal centraliser on the cement mantle and femoral stem alignment in a total hip replacement (THR). The cadaver femora were randomised into two groups. The Royal National Orthopaedic Hospital (RNOH) femoral stems were inserted to each femur using third-generation cementing technique .The first group was inserted using proximal and distal centralisers. The second group was inserted using distal centralisers only. All the hip specimens were X-rayed using high-tech scanner and computer software. The stem alignment and cement mantle were measured. We concluded that the proximal femoral centraliser improved the cement mantle distribution and femoral stem alignment in THR. This improvement will reflect on the long-term survival of the THR. We also showed an excellent and accurate way of measuring the femoral stem alignment in THR.