Standing radiological analysis with a low-dose biplanar imaging system (EOS system) of the position of the components in total hip arthroplasty using an anterior approach: a cohort study of 102 patients

• Published in: The bone & joint journal Vol. 98-B; no. 3; pp. 326 - 333
• Main Authors: Morvan, A, Moreau, S, Combourieu, B, Pansard, E, Marmorat, J L, Carlier, R, Judet, T, Lonjon, G
• Format: Journal Article
• Language: English
• Published: England 01.03.2016
• Subjects: Acetabulum - diagnostic imaging; Acetabulum - pathology; Acetabulum - surgery; Aged; Arthroplasty, Replacement, Hip - methods; Cohort Studies; Female; Femur - diagnostic imaging; Femur - pathology; Hip Joint - diagnostic imaging; Hip Prosthesis; Humans; Male; Middle Aged; Osteoarthritis, Hip - surgery; Patient Positioning - methods; Posture; Prospective Studies; Radiation Dosage; Radiography; EOS imaging system; standing position; components; anterior approach; Hip arthroplasty
• ISSN: 2049-4394; 2049-4408
• DOI: 10.1302/0301-620X.98B3.36289

The primary aim of this study was to analyse the position of the acetabular and femoral components in total hip arthroplasty undertaken using an anterior surgical approach. In a prospective, single centre study, we used the EOS imaging system to analyse the position of components following THA performed via the anterior approach in 102 patients (103 hips) with a mean age of 64.7 years (sd 12.6). Images were taken with patients in the standing position, allowing measurement of both anatomical and functional anteversion of the acetabular component. The mean inclination of the acetabular component was 39° (standard deviation (sd) 6), the mean anatomical anteversion was 30° (sd 10), and the mean functional anteversion was 31° (sd 8) five days after surgery. The mean anteversion of the femoral component was 20° (sd 11). Anatomical and functional anteversion of the acetabular component differed by > 10° in 23 (22%) cases. Pelvic tilt was the only pre-operative predictive factor of this difference. Our study showed that anteversion of the acetabular component following THA using the anterior approach was greater than the recommended target value, and that substantial differences were observed in some patients when measured using two different measurement planes. If these results are confirmed by further studies, and considering that the anterior approach is intended to limit the incidence of dislocation, a new correlation study for each reference plane (anatomical and functional) will be necessary to define a 'safe zone' for use with the anterior approach. EOS imaging system is helpful in the pre-operative and post-operative radiological analysis of total hip arthroplasty.