Sagittal Pelvic Kinematics in Hip Arthroplasty

Abstract

Purpose of review: The orientation of the spine relative to the pelvis-particularly that in the sagittal plane-has been shown in both kinematic and radiographic studies to be paramount in governance of acetabular alignment during normal bodily motion. The purpose of this review is to better understand the challenges faced by arthroplasty surgeons in treating patients that have concurrent lumbar disease and are therefore more likely to have poorer clinical outcomes after THA than in patients without disease.

Recent findings: The concept of an "acetabular safe zone" has been well described in the past regarding the appropriate orientation of acetabular component in THA. However, this concept is now under scrutiny, and rising forth is a concept of functional acetabular orientation that is based on clinically evaluable factors that are patient and motion specific. The interplay between the functional position of the acetabulum and the lumbar spine is complex. The challenges that are thereby faced by arthroplasty surgeons in terms of proper acetabular cup positioning when treating patients with concomitant lumbar disease need to be better understood and studied, so as to prevent catastrophic and costly complications such as periprosthetic joint dislocations and revision surgeries.

Keywords: Acetabular cup position; Lumbar spinal fusion; Spinopelvic mobility; Total hip arthroplasty.

Fig. 1

Spinopelvic parameters. From Delsole EM, Vigdorchik JM, Schwarzkopf R, Errico TJ, and Buckland AJ. Total hip arthroplasty in the spinal deformity population: does degree of sagittal deformity affect rates of safe zone placement, instability, or revision? J Arthroplasty. 2017; 32(6):1910–1917

Fig. 2

Relationship between pelvic rotation and acetabular anteversion during postural changes. Picture on left (labeled C) is standing and right (labeled D) is sitting. From Kanawade V, Dorr LD, Wan Z. Predictability of acetabular component angular change with postural shift from standing to sitting position. J Bone Joint Surg Am. 2014; 96(12):978–986

Fig. 3

Standing (left image) and sitting (right image) lateral radiographs. Note increased pelvic tilt with corresponding acetabular rollback (increased anteversion) when transitioning from standing to sitting. From: 39. Stefl M, Lundergan W, Heckmann N, et al. Spinopelvic mobility and acetabular component position for total hip arthroplasty. Bone Joint J. 2017; 99-B(1 Supple A):37–45

Fig. 4

Lateral body radiographs with corresponding diagrams demonstrating worsening sagittal balance with compensatory pelvic retroversion and knee flexion. Note change in acetabular anteversion corresponding to changes in global body alignment. From: Hu J, Qian BP, Qiu Y, et al. Can acetabular orientation be restored by lumbar pedicle subtraction osteotomy in ankylosing spondylitis patients with thoracolumbar kyphosis? Eur Spine J. 2017; 26(7):1826–1832

Fig. 5

Acetabular version changes with spinal deformity correction. From: Buckland AJ, Vigdorchik J, Schwab FJ, et al. Acetabular anteversion changes due to spinal deformity correction: bridging the gap between hip and spine surgeons. J Bone Joint Surg Am. 2015; 97(23):1913–20