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Updated: Jul 5, 2025
Three-Dimensional Preoperative Virtual Planning in Derotational Proximal Femoral Osteotomy
Published on: February 17, 2023
Digital protractor as an intraoperative guide to cup anteversion in total hip arthroplasty
Introduction:
To explore if digital protractor could guide the anteversion of acetabular cup during primary THA and make it consistent with preoperative.
Methods:
We retrospectively reviewed 172 cases of primary THA with direct anterior approach (DAA) over 2 years. The anteversion of acetabular cup were measured from computed tomography (CT) scan preoperative and de-identified plain radiographs postoperative by two blinded investigators who were not involved in the surgery. The effect of the digital protractor on the anteversion was determined using regression analysis.
Results:
The mean anteversion for the THAs in digital protractor group was 15.5°and 21.4°in control group (P < 0.01). The mean anteversion bias for the THAs in digital protractor group was 1.59° and 6.63° in control group (P < 0.01).Regression analysis identified a 10.7% difference in anteversion due to the use of digital protractor (P < 0.01), and THAs performed without digital protractor were six times more likely to result in anteversion of > 25°. The correlation coefficient for the interobserver reliability of the measurement of the two investigators was 0.94.
Conclusion:
The digital protractor is a practical tool in the DAA for THA to determine the anteversion of the acetabular prosthesis.
