Abstract
Objective The present study aims to assess the reproducibility of digital planning for cementless total hip arthroplasty (THA) among surgeons with different levels of experience. In addition, it attempts to determine the degree of planning reliability based on a contralateral THA or on a spherical marker positioned at the greater trochanter for calibration. Methods Two evaluators with different experience levels (A1 and A2) performed independently the retrospective digital surgical planning of 64 cementless THAs. Next, we compared the planning with the implants used in the surgery. The reproducibility was excellent when planning and implants were identical; proper in case of a single-unit variation; and inappropriate if there was variation in two or more units. The present analysis also determined the calibration accuracy between the contralateral THA and the spherical marker at the greater trochanter level. Results The present study demonstrated greater success when the most experienced evaluator performed the planning and greater accuracy for the contralateral THA. When splitting the analysis per parameter (contralateral THA or spherical marker), there was a statistical difference only for the planning of A1 and the implants used in the surgery. This difference occurred in the excellent category, with 67.3% for contralateral THA compared with 30.6% for a spherical marker ( p <0.001), and in the inappropriate category, with 7.1% for contralateral THA compared with 30.6% for a spherical marker ( p <0.001). Conclusions Digital planning is more accurate when performed by an experienced evaluator. The contralateral prosthesis head was a better reference than a marker on the greater trochanter.