LAUSR

A patient’s complexity increases, coexisting conditions require surgeons to understand the subtle interplay between orthopedic pathologies. A patient with concurrent hip osteoarthritis and degenerative lumbar spine disease, known as a hip-spine syndrome, is one example of this phenomenon. It is well established that having both spinal fusion and total hip arthroplasty (THA) is associated with increased risks, specifically hip dislocation and hip revision.1–4 Minimizing these complications by recommending the proper surgical sequence remains a point of debate among surgeons from both specialties.5 We recommend prioritizing hip arthroplasty over spinal procedures, with a few notable exceptions. In the face of irreversible damage, the procedure that prevents or mitigates the most harm should be prioritized first. An upper motor neuron or acute, evolving lower motor neuron symptoms demand urgent spine consultation and prioritization. Lumbar degenerative scoliosis is a chronic, degenerative disease and should be treated with a hip-first approach. We recommend hip arthroplasty first because it has shown to relieve associated back pain, confers theoretical biomechanical benefits, and has demonstrated a decreased association with hip dislocation and hip revision. Hip-spine syndrome is the complicated interplay of hip and spine pathology, symptoms, and biomechanics. One compelling reason in support of the hip-first approach is that eliminating hip pain has also been found to eliminate lower back pain.6,7 In one series, 66% of patients undergoing THA with concomitant back pain and without spine deformity had resolution of symptoms.7 Using the hip-first approach, the surgeon may alleviate back symptoms, thereby treating the patient’s overall condition. It is reasonable to suppose that treating the hip first may decrease additional or unnecessary procedures, though the supporting literature is currently lacking. Performing the hip arthroplasty first in a hip-spine syndrome confers theoretical biomechanical benefits. A balanced and flexible spine allows for pelvic retroversion in the sitting position while a degenerative lumbar spine decreases spinal motion altering pelvic kinematics.8,9 The virtue of having a coexisting degenerative spinal disease and hip disease means that both the spine and hip have increased rigidity. The surgical solution for the spine is more rigidity, whereas the surgical solution for the hip is more flexible. After THA, a degenerative but still semiflexible spine may allow increased capacity for the pelvic motion before dislocation. After in-growth and maturation of the postsurgical soft tissue envelope, the hip has increased capacity to tolerate a rigid spinal fusion. On the contrary, a rigid and mature spinal fusion may create a suboptimal environment for a subsequent and healing THA. Several authors have studied spine-pelvis-hip motion as it relates to acetabular opening, acetabular impingement, and prosthetic hip dislocations.10,11 They have found that biomechanical changes, both pathophysiological and surgical, predispose patients with stiffness to dislocation; identifying preoperative spinopelvic stiffness may allow surgeons to adjust hip implant position accordingly.10–13 Patients with a history of both THA and a lumbar spinal fusion (LSF) have increased risk of complications, specifically hip dislocation and revision.2 These elevated risks have prompted investigations into whether the order of surgery impacts the complication profile. In one prospective cohort study of 37 patients, authors found no difference in complication or patient-reported outcomes when comparing hip-first and spine-first patients.1 Other studies have shown that THA after LSF is associated with increased dislocation rates3 in THA after LSF and increased revision rates.4 The largest study demonstrating evidence in favor of a hip-first approach comes from a retrospective Medicare study that evaluates dislocation rate and revision rate for patients with LSF after THA and THA after LSF.14 Patients who underwent LSF after THA (n= 10,482) showed lower dislocation rates (1.7% vs. 4.6%) and lower revision rate (3.7% vs. 5.7%) when Received for publication May 12, 2020; accepted May 26, 2020. From the Department of Orthopaedics, Walter Reed National Military Medical Center, Bethesda, MD. The authors declare no conflict of interest. Reprints: Daniel L. Rodkey, MD, 2001 12th Street NW Apt 107, Washington, DC 20009 (e-mails: [email protected]; [email protected]). Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved. CONTROVERSIES IN SPINE SURGERY