A Preoperative Workup of a "Hip-Spine" Total Hip Arthroplasty Patient: A Simplified Approach to a Complex Problem.

Overview

BACKGROUND: A large body of evidence has confirmed that patients with spinal deformity, lumbar fusion, and abnormal spinopelvic mobility are at significantly increased risk for instability, dislocation, and revision after total hip arthroplasty (THA). METHODS: Achieving a stable construct in patients with pre-existing spine disease requires an understanding of basic spinopelvic parameters and the compensatory mechanisms associated with abnormal spinopelvic motion. Indicated patients with concomitant hip-spine pathology should be assessed for (1) the presence of spinal deformity and (2) the presence of spinal stiffness before undergoing THA. Preoperative imaging should include a standing anteroposterior pelvis x-ray, as well as two lateral spinopelvic radiographs in the standing and seated position. RESULTS: Based on the presence of spinal deformity and/or spinal stiffness, patients may be categorized as one of the four groups of the "Hip-Spine Classification in THA." A series of illustrative case examples is provided. CONCLUSION: A simple three-step assessment with minimal measurements will effectively identify the complex "hip-spine" THA patient at high risk for postoperative instability. Adhering to group-specific recommendations for acetabular cup position can help to further reduce the burden of instability and related revisions in this challenging population.