Accuracy of acetabular cup placement in computer-assisted, minimally-invasive THR in a lateral decubitus position

Abstract

In a prospective and randomised clinical study, we implanted acetabular cups either by means of an imagefree computer-navigation system (navigated group, n=32) or by free-hand technique (freehand group n=32, two dropouts). Total hip replacement was conducted in the lateral position and through a minimally invasive anterior approach (MicroHip). The position of the component was determined postoperatively on CT scans of the pelvis using CT-planning software. We found an average inclination of 42.3°(range 32.7-50.6°; SD±3.8°) and an average anteversion of 24.5°(range 12.0-33.3°; SD±6.0°) in the computer-assisted study group and an average inclination of 37.9°(range 25.6-50.2°; SD±6.3°) and an average anteversion of 23.8°(range 5.6-46.9°; SD±10.1°) in the freehand group. The higher precision of computer navigation was indicated by the lower standard deviations. For both measurements we found a significant heterogeneity of variances (p<0.05, Levene's test). The mean difference between the cup inclination/anteversion values displayed by computer navigation and the true cup position (CT control) was 0.37°(SD 3.26) and −5.61°(SD 6.48), respectively. We found a bias (underestimation) with regard to anteversion determined by the imageless computer navigation system. A bias for inclination was not found. Registration of the landmarks of the anterior pelvic plane in lateral position with undraped percutaneous methods leads to an error in cup anteversion, but not to an error in cup inclination. The bias we found is consistent with a correct registration of the anterosuperior iliac spine (ASIS) and with a registration of the symphysis 1 cm above the bone, corresponding to the less compressible overlying soft tissue in this region. There was no significant correlation between the bias and the thickness of soft tissue above the pubic tubercles. We suggest use of a percutaneous registration of ASIS and an invasive registration above the pubic tubercles when computer-assisted navigation is performed in minimally invasive THR in a lateral position.

Navigation is Equal to Estimation by Eye and Palpation in Preventing Psoas Impingement in THA

“…The use of navigation also has general limitations. First, especially in patients who are obese, pelvic landmarks can become obscured by overlying soft tissue, which can make direct referencing for computer-assisted surgery difficult [18,21]. Second, computers are susceptible to electronic failure, which happened once during our study.…”

A Smart Tool for Intraoperative Leg Length Targeting in Total Hip Arthroplasty: A Retrospective Cohort Study

“…Indeed, in our study, the average procedure time was 76 minutes, which compares favourably with procedures utilizing mechanical measurement techniques, which range in duration from 73 [23, 44] to 104 minutes [45]. Conversely, computer-assisted navigation is associated with significant increases in procedural time, reported between 12 [46, 47] and 23 added minutes [23, 44, 45, 48]. …”

Decreased femoral periprosthetic bone mineral density: a comparative study using DXA in patients after cementless total hip arthroplasty with osteonecrosis of the femoral head versus primary osteoarthritis

“…Most important, in the present investigation a significant lower BMD for ROI 1 and 7 of the femoral periprosthetic bone stock in patients who received a THA due to ONFH was found. In the past, many studies using DXA in THA have focused on measuring postoperative bone mineral density in correlation to different prosthetic designs and component coatings [7,8,[15][16][17][18][19] and a few investigated the effects of different surgical techniques on bony ingrowth as well [20,21]. None focused on ONFH up to now.…”