Total Hip Prostheses in Standing, Sitting and Squatting Positions: An Overview of Our 8 Years Practice Using the EOS Imaging Technology

Abstract

More total hip arthroplasty (THA) is performed worldwide and especially in younger and more active patients compared to earlier decades. One of the focuses of THA research in the future will be on optimizing the radiological follow-up of these patients using 2D and 3D measurements of implants position while reducing the radiation dose delivered.Low-dose EOS® imaging is an innovative slot-scanning radiograph system providing valuable information in patient functional positions (standing, sitting and even squatting positions). EOS has been proven accurate and reliable without significant inconvenience caused by the metallic artifacts of implants. The ability to obtain precise data on implant orientation according to the patient posture opens new perspectives for a comprehensive analysis of the pelvic frontal and sagittal balance and its potential impact on implants function and failures.We report our 8 years experience on our first 300 THA patients using this technology routinely for pre and post op evaluation. Our results will be compared and confronted with the actual literature about this innovative technology. We shall especially emphasize our experience about patients with abnormal posture and the evolution of the subject over time, because the phenomenon of an aging spine is frequently associated with the process of aging hips.

Accuracy and Precision of an Ultrasound‐Based Device to Measure the Pelvic Tilt in Several Positions

“…Some authors used the EOS imaging system (EOS Imaging, SA, Paris, France), allowing 3D measurements on biplanar low‐dose radiographs. Pelvic parameters were measured according to the sitting and the standing positions . However, even if measurements seem to be reliable, the access to this device still remains limited.…”

“…Pelvic parameters were measured according to the sitting and the standing positions. 17,18 However, even if measurements seem to be reliable, 19 the access to this device still remains limited. Other studies used a localized digitizer to identify bony landmarks.…”

The global alignment in patients with lumbar spinal stenosis: our experience using the EOS full-body images

“…This high percentage points out the importance of the global evaluation of the patient: the spine evaluation cannot be performed without a careful analysis of the lower limbs ( Figs. 10, 11) [22]. The key points for sagittal balance analysis in spinal stenosis patients are the detection of imbalance, the appreciation of its severity, and the diagnosis of combined problems involving the lower limbs.…”

“…Using the simultaneous AP and lateral EOS images, we measured the classical spinopelvic parameters to assess the sagittal balance condition [pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), C7 sagittal vertical axis (SVA), and global tilt (GT)] [21]. PT modifications were evaluated according to the incidence angle [22]. We also evaluated the lower limbs position (HKA angle, femoral sagittal tilt angle FST, knee flexion angle KFA, and sacro-femoral angle SFA) [22].…”

“…PT modifications were evaluated according to the incidence angle [22]. We also evaluated the lower limbs position (HKA angle, femoral sagittal tilt angle FST, knee flexion angle KFA, and sacro-femoral angle SFA) [22]. Pelvic frontal inclination was measured using the pelvic obliquity angle (POA) (angle between the horizontal line and the line through the femoral head centers) (Figs.…”