Accuracy of cup orientation and learning curve of the accelerometer-based portable navigation system for total hip arthroplasty in the supine position

Background: Accelerometer-based portable navigation systems in supine total hip arthroplasty (THA) have been developed, but there are no reports on the accuracy of cup placement. We aimed to investigate and compare the accuracy of the accelerometer-based portable navigation system versus the acetabular alignment guide placed on the pelvis in THA using the direct anterior approach (DAA). Both devices tracked changes in the pelvic position. Methods: In this single-centre, retrospective study, we reviewed 115 hips in 113 patients who underwent primary THA via the DAA using an accelerometer-based portable navigation system in the supine position (portable navigation group) and 106 hips in 101 patients who underwent THA using an acetabular alignment guide (alignment guide group) as controls. Hips were evaluated postoperatively using computed tomography to measure cup orientation. The accuracy of cup orientation was compared between the 2 groups. Results: Absolute values of inclination error were 3.1° ± 2.2° and 2.9° ± 2.3° ( p = 0.708) in the portable navigation and alignment guide groups and those of anteversion error were 2.8° ± 2.3° and 3.7° ± 2.7°, respectively ( p = 0.005). The number of cups placed within 10° of error was 98.3% and 96.2% in the portable navigation and alignment guide groups, respectively ( p = 0.304). The portable navigation group had significantly more hips (72.2%) placed within a 5° margin of error than did the alignment guide group (56.6%) ( p = 0.016). Conclusion: High accuracy in cup placement was achieved using accelerometer-based portable navigation in supine THA. Using a navigation system may contribute to improved long-term outcomes.

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The Accuracy And Influencing Factors of An Accelerometer-Based Portable Navigation System For Total Hip Arthroplasty In The Supine Position : A Prospective Multicenter Study Using 3D CT Measurement

10.21203/rs.3.rs-902612/v1 ◽

2021 ◽

Author(s):

Yukihide Minoda ◽

Masayuki Ito ◽

Kentaro Iwakiri ◽

Katsufumi Uchiyama ◽

Masashi Kawasaki ◽

...

Keyword(s):

Total Hip Arthroplasty ◽

Hip Arthroplasty ◽

Supine Position ◽

Navigation System ◽

Pelvic Tilt ◽

Intraoperative Navigation ◽

3D Ct ◽

Pelvic Rotation ◽

Total Hip ◽

Portable Navigation

Abstract This multicenter prospective study aimed to evaluate the accuracy of a newly introduced accelerometer-based portable navigation system for total hip arthroplasty (THA) in the supine position. Three hundred twenty-four THAs using supine position in 9 hospitals were prospectively enrolled in the study. An accelerometer-based portable navigation system was used for cup fixation and the intraoperative navigation data (cup alignment, pelvic tilt, and pelvic rotation) were recorded. Postoperative cup alignment was measured on 3D-CT images. The accuracy (absolute difference in cup alignment between the intraoperative navigation record and postoperative 3D-CT measurements) was 3 ± 3° (mean ± standard deviation) for cup inclination and 3 ± 3° for cup anteversion. The pelvis tilted anteriorly in 148 hips (46%) and posteriorly in 162 hips (50%), and did not tilt in 14 hips (4%). The pelvis rotated toward the operating side in 179 hips (55%), toward the contralateral side in 112 hips (35%), and did not rotate in 33 hips (10%). Multiple regression analysis showed that the patients’ characteristics, pelvic tilt, and pelvic rotation did not affect the accuracy of the navigation system. The accuracy was 3 ± 3° and not affected by patient characteristics, surgical factors, or substantial pelvic movement during cup fixation.

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