PurposeThis study sought to identify key postoperative complications and clinical outcomes in patients with Ankylosing Spondylitis (AS) undergoing total hip arthroplasty (THA).MethodsThis systematic review evaluated postoperative complications and clinical outcomes in this population by querying PubMed, Embase, and CINAHL, up till June 19th, 2024.ResultsNineteen observational studies (n = 2003; 81.72 % male; mean age 38.95 ± 10.08 years; mean follow-up 76 ± 22.10 months) were included. Surgical approaches were posterolateral (n = 11 studies), Watson-Jones anterior (n = 1 study), and minimally invasive 2-incision (n = 1 study). Complications included infection (n = 65; 5.14 %), heterotopic ossification (n = 51; 4.03 %), prosthetic joint noise (n = 24; 1.90 %), perioperative fracture (n = 18; 1.42 %), improper implant placement (n = 14; 1.11 %), re-infection (n = 11; 0.87 %), and implant loosening (n = 8; 0.63 %). Hip dislocation occurred in 2.64 % (n = 22) of patients across 8 studies, and 4.06 % (n = 21) of patients required revision THA in six studies for various reasons, such as leg length discrepancy, joint loosening, or instability. HO was reported in 11 studies (n = 880), affecting 15.11 % (n = 133/880) of patients. All four studies assessing range of motion (ROM) found significant improvement after THA.ConclusionObserved trends suggest a noticeable occurrence of complications, such as joint dislocation and HO, following THA in patients with AS. While postoperative improvements in ROM and patient outcomes were reported, these qualitative findings warrant further investigation to confirm their significance. We recommend increased awareness and the exploration of strategies to minimize the risk of complications for high-risk patients with history of HO and other preexisting comorbidities to prevent progression of the complication profile seen in patients with AS.