Proposal of accurate cup placement procedure during total hip arthroplasty based on pelvic tilt discrepancies in the lateral position

Manabu Tsukamoto,Makoto Kawasaki,Teruaki Fujitani,Hitoshi Suzuki,Akinori Sakai

doi:10.1038/s41598-021-93418-y

Manabu Tsukamoto, Makoto Kawasaki + Show 3 more

Open Access

https://doi.org/10.1038/s41598-021-93418-y

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Abstract

By combining the anatomical-pelvic-plane (APP) positioner with a newly improved navigation system during total hip arthroplasty (THA), it is theoretically possible to determine cup orientation based on the APP while tracking pelvic movement. The purpose of this study was to determine the navigation accuracy and whether the error is related to the pelvic position fixed by the positioner. Fifty hips that underwent primary THA between 2018 and 2020 were analysed. The accuracy was 2.34° at radiographic inclination (RI) and − 5.01° at radiographic anteversion (RA), and the error was within 10° at both RI and RA in only 40 of 50 hips (80.0%). The discrepancy in pelvic sagittal tilt was correlated with the cup orientation error and especially strongly correlated with the RA error (r = − 0.751, p < 0.001). When RI and RA were calculated using a correction formula to determine the true cup orientation based on the pelvic tilt discrepancies, the error in both RI and RA was within 10° in all cases (100%). The navigation accuracy is related to the pelvic position fixed by the positioner, and the correction formula for the target angle that considers pelvic tilt discrepancies can lead to accurate cup placement in the future.

Highlights

By combining the anatomical-pelvic-plane (APP) positioner with a newly improved navigation system during total hip arthroplasty (THA), it is theoretically possible to determine cup orientation based on the APP while tracking pelvic movement
The aims of this study were to determine the accuracy of the portable accelerometer-based navigation system (PNS) combined with the APP positioner and whether the cup orientation error is related to the position of the pelvis fixed by the APP positioner
We assumed that the TPP and APP were made parallel by the APP positioner, and the radiographic inclination (RI) and radiographic anteversion (RA) angles based on the navigation record (NR) were calculated considering the pelvic inclination of the APP in the supine position (PIAPP)

Summary

Introduction

By combining the anatomical-pelvic-plane (APP) positioner with a newly improved navigation system during total hip arthroplasty (THA), it is theoretically possible to determine cup orientation based on the APP while tracking pelvic movement. The authors created a mechanical cup navigator attachable to the APP positioner and demonstrated that this device helps accurately place c ups[6] They showed that accurate pelvic positioning and cup placement are possible by using an APP positioner; no consideration was given to intraoperative pelvic movement in their studies. By combining the APP positioner with the PNS, it is theoretically possible to determine the cup orientation based on the APP while tracking the movement of the pelvis during the operation If this procedure causes a large error in the cup orientation, it is likely that the initial pelvic position determined by the APP positioner deviates. In addition to the Scientific Reports | (2021) 11:13870

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