Introduction: The Hip-Spine Relationship in Total Hip Arthroplasty

It is with great honor and profound sadness that I write to introduce this symposium from the 2020 Annual Meeting of the American Association of Hip and Knee Surgeons (AAHKS). This specific symposium on the hip-spine relationship takes root from a similar symposium we highlighted at the 2018 and 2019 Annual Meetings with the late Dr. Lawrence Dorr as a member of the faculty. Many of us reading today owe a tremendous amount of gratitude to the time and energy Dr. Dorr spent teaching us about everything hip surgery related, and specifically his latest interest in the hip-spine relationship, defining the concept, and coining the terms “anteinclination,” “stuck-standing,” and “stuck-sitting.” We hope to continue learning and advancing this field in his honor.

Dislocation following total hip arthroplasty (THA) remains a devastating side effect despite technological, technical, and implant advancements. The relationship between poorer outcomes in patients with concomitant hip and spinopelvic pathology following THA has been well-documented. Hip and spine pathology often coexist, with a reported 3.5% of THA patients having undergone a prior spinal surgery. The increasing number of THA and lumbar spine fusion procedures being performed in the United States underscores the importance of systematic spinopelvic evaluation in all patients prior to THA.

Most importantly, we need to learn how to identify patients who are at risk of complications. A thorough spinopelvic workup is important to not only detect patients with spinopelvic pathology but also to prevent inadvertent oversight of patients with a biologic spinal fusion or other etiologies of spinal stiffness that may be less apparent than an instrumented fusion on radiographs. Recent evidence demonstrates that the vast majority (81%) of THA patients with stiff spines do not have an instrumented fusion and that the prevalence of spinopelvic risk factors for adverse spinopelvic mobility is significant in THA patients, further emphasizing the need for a standardized hip-spine evaluation of all patients undergoing THA.

This symposium will focus on the identification and workup of high-risk patients, and then the treatment strategies in each particular case, ensuring a fair viewpoint from both anterior-based and posterior approach surgeons. Patients with spinal stiffness and/or spinal deformity can still safely undergo a primary THA without significantly increased risk of dislocation or revision, provided that appropriate care in preoperative planning and surgical execution is performed.