Malkani A, et al. - Data from 2005 to 2015 was assessed to compare dislocation and revision risks in subjects with primary total hip arthroplasty (THA) with pre-existing lumbar spine fusion (LSF) vs THA with LSF within 1, 2 and 5 years after the index THA. After adjusting for age, socioeconomic status, race, census region, gender, Charlson score, preexisting conditions, discharge status, length of stay and hospital characteristics, multivariate cox regression analysis was performed. They observed an increased risk of 106% of dislocation in cases with prior LSF undergoing THA as compared to those with LSF done 5 years after THA. At 1, 2 and 5 years post THA, the risk of revision THA was higher in the preexisting LSF group by 43%, 41%, and 49% as compared to THA done first with subsequent LSF. Dislocation was the most common cause for revision THA especially in the prior LSF group with incidence of 26.6%.