Evaluation of the native femoral neck and stem version reproducibility using robotic-arm assisted direct-anterior total hip arthroplasty.

The intraoperative measurement of the femoral version (FV) has gained attention in wake of an optimised combined version (CV) philosophy. Whereas some data is available utilising different approaches, to our belief this study provides the first in vivo FV data in DA-THA using the MAKO™ robot. To improve the accuracy of the femoral stem version in DA-THA, we want to ask the following question: How effectively can we reproduce the native femoral version in DA- THA using the MAKO™ robot? The first 125 total hip cases through DAA with the use of the combined anteversion concept and the help of the MAKO™ robot from a single institution, single surgeon from January 2020 to July 2021 were retrospectively analysed. The native version (NV) and broach version (BV) were determined with the use of the MAKO™ preoperative computed tomography planning software. The data of the NV and BV of 115 withheld patients was normally distributed. The native femoral version ranged from -12° till 33° (mean 7,8° +/- 8,1) and the broach version ranged from -18° till 43° (mean 8,2° +/- 9,9). The Pearson correlation coefficient between the NV and BV was 0,78. The native femoral version can be reproduced by broaching the proximal femur, in a robotically implanted direct anterior cementless THA, with 78% effectiveness. Stem placement seemed to be more precise with growing experience, however this appeared not to be significant.