The Impact of Spino-Pelvic Alignment on Total Hip Arthroplasty Outcomes: A Critical Analysis of Current Evidence

In this review, we (1) evaluated the effect of adult spine deformity (ASD) and its surgical correction on patients who had a total hip arthroplasty (THA); (2) evaluated the outcomes of THA in patients who have had previous spinal fusion; and (3) we presented an algorithm on how to surgically address patients who simultaneously require THA and ASD correction.A comprehensive literature search was conducted. Our final analysis included 14 studies. Overall, there were 3 studies that reported on the impact of ASD on THA outcomes, 6 studies reported on the effect of ASD correction on THA outcomes, and 5 studies reported on the effect of spinal fusion on THA outcomes.Patients with concurrent ASD and THA are at increased risk of THA dislocations and revisions with studies reporting a compiled 2.9% dislocation rate in 1167 patients. Patients who underwent ASD correction demonstrated a post-operative reduction of acetabular anteversion (mean reduction range 4.96°-11.2°, P.001) and tilt (mean -7° ± 10°, P.001). In THA patients with concurrent lumbosacral fusion, dislocation rates ranged between 3% at 1 year and 7.5% at 2 years compared to 0.4%-2.1% dislocation rates in matching cohorts (P.001).Spine balance can alter THA outcomes, but the exact mechanism is yet to be elucidated. We aimed at bridging the gap between hip and spine surgeons with an up-to-date analysis of the best available evidence and presented an algorithm for approaching patients who may simultaneously need ASD correction and THA.