Pelvic tilt between supine and standing after total hip arthroplasty an RSA up to seven years after the operation

Abstract

The pose of the prosthetic components after total hip arthroplasty (THA) is commonly evaluated on conventional radiographs. Any change of the pelvic position after the operation in supine and between supine and standing position with time will influence validity of the measurements. We evaluated the changed pelvic tilt angle (PTA) in supine and standing position up to 7 years after operation. The aims of our study were (a) to evaluate if the PTA change over time after THA, (b) to assess any difference in PTA between supine and standing positions, and (c) to investigate whether factors such as gender, the condition of the opposite hip or low-back pain have any influence on PTA after THA. Repeated radiostereophotogrammetric radiographs of 106 patients were studied. Patients had been examined in the supine position postoperatively, and in both supine and standing positions at 6 months and 7-year follow-up. Measurements of supine patients showed an increasing mean posterior pelvic tilt over time. From supine to standing, the pelvis tilted in the opposite direction. At 6 months, the mean anterior tilt was 3.6°± 3.8°(confidence interval [CI]: 2.8°to 4.3°) which increased to 6.4°± 3.9°(CI: 5.7°to 7.2°) at 7 years. The mean changes in pelvic rotations around the longitudinal and sagittal axis were less than 1 degree, in both positions. In individual patients, this change reached about 11.0 degrees in supine and 18.0 degrees when standing.

Change of Pelvic Sagittal Tilt after Total Hip Arthroplasty in Patients with Bilateral Crowe Type IV Developmental Dysplasia of the Hip

“…The Influence of PST and Radiographic Position Babisch et al 32 reported that when using preoperative radiographs to inform the placement of the acetabular component, surgeons should note the dynamic change of PST and effect on postoperative acetabular alignment, which could decrease the occurrence of adverse outcomes, such as the dislocations in our study. 17,22,33,34 Routinely, the observation of the pelvis is determined by radiographs in the supine position in perioperative period, 17 and the measurement of PST from a single supine film is valid and reliable for evaluating the pelvic position. 17,26,[33][34][35] In addition, AP pelvic radiographs remain the standard of care imaging modality for pre and postoperative assessment during THA owing to easy accessibility, cost effectiveness, low radiation exposure, and widespread availability, 18,26,33,36 and the use of AP radiographs to assess changes in pelvis has been validated, 34,37 which proved that the position and radiographic methods we used in this study was appropriate.…”

“…17,22,33,34 Routinely, the observation of the pelvis is determined by radiographs in the supine position in perioperative period, 17 and the measurement of PST from a single supine film is valid and reliable for evaluating the pelvic position. 17,26,[33][34][35] In addition, AP pelvic radiographs remain the standard of care imaging modality for pre and postoperative assessment during THA owing to easy accessibility, cost effectiveness, low radiation exposure, and widespread availability, 18,26,33,36 and the use of AP radiographs to assess changes in pelvis has been validated, 34,37 which proved that the position and radiographic methods we used in this study was appropriate. And radiographic overlap could occur in a lateral position between right and left hips, making the diagnostic evaluation complicated and less efficient.…”

“…Change of pelvic sagittal tilt (PST) before and after THA caused by DDH reveals that operations have effects on the pelvic sagittal plane and the anteversion angle of the acetabulum. 14 , 15 , 16 , 17 , 18 , 19 , 20 Though Blondel et al . 19 reported no significant change in pelvic morphology after THA for unilateral OA with a 3‐year follow‐up, and Maratt et al .…”

“…Change of pelvic sagittal tilt (PST) before and after THA caused by DDH reveals that operations have effects on the pelvic sagittal plane and the anteversion angle of the acetabulum 14–20 . Though Blondel et al 19 .…”

“…[10][11][12][13] Change of pelvic sagittal tilt (PST) before and after THA caused by DDH reveals that operations have effects on the pelvic sagittal plane and the anteversion angle of the acetabulum. [14][15][16][17][18][19][20] Though Blondel et al 19 reported no significant change in pelvic morphology after THA for unilateral OA with a 3-year follow-up, and Maratt et al 21 studied 138 patients with unilateral OA before and 6 weeks after THA and found that the change of pelvic tilt in all patients had no significant differences. Also, Tamura et al 15 reported a 10-year follow-up of patients with OA undergoing THA and found that the PST in the supine position showed no significant changes.…”