[Evaluation of spino-pelvic mobility; its importance in preventing total hip replacement dislocation]

Recently, it has been recognized that changes in sagittal alignment and spinopelvic mobility due to alterations of the lumbosacral spine can influence the dislocation of a hip replacement. The biggest difficulties for this problem are: a) the bibliography related to this topic has been written in English and there is confusion in its terminology; b) there is no consensus on what parameters should be used to identify, measure, and estimate the risks of dislocation occurring; c) the basic concepts that interrelate spinal disorders and prosthetic dislocation are not clearly understood; and d) spine and hip surgeons pursue different goals. The objective of this narrative review is to overcome the aforementioned difficulties by using a strategy to answer some questions: Is hip dislocation really a problem? What is the interrelationship between alterations in the pelvic spinal balance and the dislocation of a prosthesis? How is sagittal balance and lumbosacral mobility defined and how can their alterations be measured? What are their compensatory mechanisms to achieve a good functioning and how these mechanisms can be used to correctly orient the acetabulum? To document this review, we consulted the databases of PubMed, Scopus, SciELO and Google Scholar with the keywords: Spinopelvic, Total Hip Arthroplasty, Hip Dislocation, Spine-Pelvis-hip Arthroplasty. The articles that, in the author's opinion, were the most objective and/or relevant for the study of this topic were selected.