Postoperative Hip Center Position Associated With the Range of Internal Rotation and Extension During Gait in Hip Dysplasia Patients After Total Hip Arthroplasty

Abstract

Background: Total hip arthroplasty (THA) for hip dysplasia patients is sometimes complex and compromises pathomorphological changes in these patients. However, it remains unclear whether it is preoperative deformities or postoperative structures or anatomic changes during THA that have the most remarkable correlation with the hip dynamic function during gait. The purpose of this study was to investigate this relationship and propose insights into the surgical reconstruction strategy in patients with developmental dysplasia of the hip.Methods: A total of 21 unilateral hip dysplasia patients received computed tomography scans for the creation of 3D hip models before surgery and at the last follow-up. Acetabular and femoral orientations, hip center positions, and femoral length were measured before and after THA. Hip kinematics of the operated side during gait was quantified using a dual fluoroscopic imaging technique. Pearson correlation and multiple linear regression were performed to evaluate the relationship between hip maximum range of motion in six directions and demographics characters and above hip anatomic parameters before and after THA and their changes in surgery.Results: Pearson correlation analysis found significant correlations with the gait range of motion mainly in postoperative structures, including postoperative hip center positions and acetabulum and combined anteversion. Further multiple linear regression indicated that a laterally placed hip center was significantly correlated with an increased internal rotation (R2 = 0.25, p = 0.021), which together with increased postoperative acetabulum anteversion explained 45% of external rotation decreasing (p = 0.004). A proximally placed hip center was correlated with more extension (R2 = 0.30, p = 0.010). No significant demographic characters or preoperative deformities or surgical changes were included into other multiple regression models.Conclusion: Strong correlations between postoperative structures, especially hip center positions and gait range of motion in unilateral hip dysplasia patients after THA were found. It indicated that postoperative prosthesis structures, particularly hip center positions had significant impact on the hip gait motion range and should be treated with particular caution in surgery.

Postoperative hip center position is associated with gait symmetry in range of axial rotation in dysplasia patients after THA

“…Elevated hip centers have been reported to lead to a less extended ROM of the affected side in patients during gait ( 20 ). A similar negative regression relationship between center height and extension range was also observed by Hu et al ( 46 ). While in our study, different results were found that a distally placed HRC was associated with increased SI values for adduction-abduction in the frontal plane.…”

Comparison between two- and three-dimensional methods for offset measurements after total hip arthroplasty

“…However, if the decreased acetabular offset was not compensate and only the original femoral offset was restored, the global offset will be reduced. Several studies have reported that change of the hip centre affect the biomechanics of the hip 27 , 28 . To maintain global offset, medialization should theoretically be compensated for by an equivalent increase in femoral offset 10 .…”

Acetabular Revision Arthroplasty Based on 3-Dimensional Reconstruction Technology Using Jumbo Cups

“…In a retrospective study, Dou et al (2013) found that acetabular revision increased HCOR elevation, thus resulting in leg length differences. Hu et al (2022) found that laterally or superiorly placed HCOR would increase abnormal extension and internal rotation, resulting in impaired gait patterns. These aspects need attention, especially for largely HCOR elevation in acetabular revision.…”

“…This also reminds us that upshifting the HCOR will increase the load pressure, thus increasing the wear of the prosthesis due to increased friction at the interface. In addition, the HCOR elevation will lead to differences in the leg length and postoperative kinematics ( Karaismailoglu et al, 2019 ; Hu et al, 2022 ). In a retrospective study, Dou et al (2013) found that acetabular revision increased HCOR elevation, thus resulting in leg length differences.…”