Predicting femoral head diameter and lesser trochanter to center of femoral head distance: a novel method of templating hip hemiarthroplasty.

Lesser-trochanter-to-center-of-femoral-head-distance (LTCHD) is commonly used in hip reconstruction. Demographic and radiographic variables were analyzed to predict the LTCHD and femoral head size (FHS). Two hundred twenty six patients after hip arthroplasty and 136 patients after hip hemiarthroplasty (HA) were retrospectively reviewed. Five variables significantly affected the LTCHD and four affected the FHS. For LTCHD, it was relative neck length (RNL), gender, height, race, age and weight. For FHS it was gender, height, age and race. The average predicted LTCHD was within 2.86 mm, and the FHS was 1.63 ± 1.10mm of the intra-operative measurements. By using our regression formulas the LTCHD and FHS can be calculated preoperatively to help improve precision in leg length and offset reconstruction.