The Use of the Posterior Lesser Trochanter Line to Estimate Femoral Neck Version

We hypothesized that the lesser trochanter could be a useful guide for estimating femoral component version during total hip arthroplasty. We conducted a study of 88 patients to evaluate the relationship between the posterior lesser trochanter line (PLTL) and the femoral neck axis (FNA) using computed tomographic scans. The mean angle between the PLTL and the FNA was 17.4 degrees +/- 7.1 degrees (range, -1.6 degrees to 36.5 degrees). The PLTL angle correlated (r(2) = 0.67-0.72) with the FNA angle. Intraclass correlation coefficient values showed a high level of intraobserver and interobserver agreement in the angles between the PLTL and the FNA. We found a constant relationship between the lesser trochanter and the FNA, and femoral neck version can be estimated, using the PLTL, with reasonable reliability.