Why revision of total hip arthroplasty fails: a retrospective consecutive cohort study of 963 patients.

Aims: The aims of this study are to identify the causes and independent risk factors for failure following revision total hip arthroplasty (RTHA). Methods: We conducted a retrospective multicentre cohort study involving 963 patients who underwent RTHA between January 2016 and December 2021 across three French university hospitals, with a minimum follow-up of two years. Data collected included demographic details, revision rank (R1= first revision, Results: The mean patient age was 72 years (14 to 104), with 55% of patients being female. The most common indications for RTHA were aseptic loosening (35.6%), periprosthetic fracture (32.0%), periprosthetic joint infection (PJI; 15.2%), and dislocation (5.7%). Failure occurred in 135 patients (14.0%), most frequently due to PJI (53%), of which 61% were new infections. Among patients revised for dislocation, recurrent instability accounted for 43.7% of failures. Most failures (70%) occurred within one year of revision. Independent risk factors included age ≥ 75 years (odds ratio (OR) 0.61), revision rank ≥ 3 (OR 1.96), PJI (OR 2.0), dislocation (OR 2.86), use of revision (OR 2.38), and constrained acetabular cups (OR 5.38). Conclusion: Aseptic loosening remains the leading indication for revision surgery, while PJI is the principal cause of failure following RTHA, both as a new infection and as iterative failure. Recurrent dislocation continues to pose a complex challenge despite modern implant strategies, underscoring the need for meticulous surgical planning in high-risk patients.