A systematic approach to the hip-spine relationship and its applications to total hip arthroplasty

Abstract

There remains confusion in the literature with regard to the spinopelvic relationship, and its contribution to ideal acetabular component position. Critical assessment of the literature has been limited by use of conflicting terminology and definitions of new concepts that further confuse the topic. In 2017, the concept of a Hip-Spine Workgroup was created with the first meeting held at the American Academy of Orthopedic Surgeons Annual Meeting in 2018. The goal of this workgroup was to first help standardize terminology across the literature so that as a topic, multiple groups could produce literature that is immediately understandable and applicable. This consensus review from the Hip-Spine Workgroup aims to simplify the spinopelvic relationship, offer hip surgeons a concise summary of available literature, and select common terminology approved by both hip surgeons and spine surgeons for future research. Cite this article: Bone Joint J 2019;101-B:808–816.

Sagittal Spinopelvic Translation Is Combined With Pelvic Tilt During the Standing to Sitting Position: Pelvic Incidence Is a Key Factor in Patients Who Underwent THA

“…Sitting images were obtained while the patients sat on a backless seat in accordance with a previously published protocol (feet flat on the floor, patient in a relaxed position, knees flexed 90 , horizontal gaze). Postoperative EOS images were obtained between 6 and 9 months after surgery when patients had achieved most of their functional improvement with minor improvements expected to be achieved within 2 years after THA (mean: 9 months [6][7][8][9][10][11][12][13]).…”

“…Recent literature has reported the postural changes from standing to sitting, which can tremendously affect the stability of total hip arthroplasty (THA) [1][2][3][4][5][6]. The pelvis kinematics in standing to sitting transition is commonly considered as a rotation around the axis that connects the center of the 2 femoral heads (hip axis).…”

Utility of Upright Weight-bearing Imaging in Total Hip Arthroplasty

“…31 The Hip-Spine Workgroup, a small consortium of surgeons who have driven most of the research in this field, advocate that four static radiographs be obtained in preparation for surgery: a supine AP pelvis, a standing AP pelvis, a standing lateral pelvis, and a seated lateral pelvis. 32 Ideally these images are obtained on 36-inch radiographic cassettes or by stereoradiography (EOS Imaging, Paris, France); however, in many cases a smaller cassette can still be useful. The standing and the supine AP pelvis radiographs are compared to assess for spinal deformity.…”

“…For these patients, the Hip-Spine Study Group made a recommendation for increasing acetabular anteversion to prevent a posterior dislocation. 32 Planning of acetabular component orientation may be based on several factors including existing bone stock, limblength discrepancy, or fixed pelvic obliquity from spinal deformity. 1 In addition, planned anteversion should be adjusted to account for standing and functional pelvic tilt.…”

“…1 In addition, planned anteversion should be adjusted to account for standing and functional pelvic tilt. 32,35 The lumbopelvic mobility data derived from functional weightbearing radiography may also influence component choice, with some authors advocating for the use of a dual-mobility femoral head in an effort to maximize stability. 36…”