Applying the hip-spine relationship in total hip arthroplasty

Abstract

Total hip arthroplasty dislocations that occur inside Lewinnek’s anatomical safe zone represent a need to better understand the hip-spine relationship. Unfortunately, the use of obtuse and redundant terminology to describe the hip-spine relationship has made it a relatively inaccessible topic in orthopaedics. However, with a few basic definitions and principles, the hip-spine relationship can be simplified and understood to prevent unnecessary dislocations following total hip arthroplasty. In the following text, we use common language to define a normal and abnormal hip-spine relationship, present an algorithm for recognising and treating a high-risk hip-spine patient, and discuss several common, high-risk hip-spine pathologies to apply these concepts. Simply, high-risk hip-spine patients often require subtle adjustments to acetabular anteversion based on radiographic evaluations and should also be considered for a high-offset stem, dual-mobility articulation, or large femoral head for additional protection against instability and dislocation.