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Objectives and questions: Total hip arthroplasty (THA) is among the most frequently performed and successful orthopaedic procedures worldwide, relieving pain and improving mobility in advanced hip pathology. However, patients with neurological or psychiatric comorbidities represent a distinct population whose perioperative risks and long-term outcomes are not fully understood. Determining whether these conditions increase revision or mortality rates is thus crucial. In this study, we examine periprosthetic fractures, dislocations, and implant loosening following primary THA to elucidate the impact of neurological or psychiatric disorders on these complications.

Material and methods: From the German Arthroplasty Registry (Endoprothesenregister Deutschland, EPRD), 87,878 cases with and 87,878 without neurological/psychiatric conditions were included after 1:1 matching. Demographic data (age, sex, BMI, Elixhauser score), along with revision and mortality rates, were collected. Kaplan-Meier analyses and log-rank tests assessed complications (fractures, dislocations, loosening, “other reasons”) over up to eight years.

Results: Kaplan–Meier analyses revealed a significantly higher cumulative revision rate for patients with neurological and/or psychiatric comorbidities (log-rank, P < 0.0001). Revision incidence was stratified by cause and primarily driven by increased periprosthetic fractures (P< 0.0001) and dislocations (P < 0.0001), with loosening (P < 0.0001) and other causes (P < 0.0001) also more frequent. Mortality was significantly higher in the cohort with neurological/psychiatric conditions (12 vs. 8.5%, P < 0.001).

Discussion and conclusion: Neurological and/or psychiatric conditions are associated with a heightened risk of periprosthetic fractures, dislocations, and loosening following THA, most pronounced within the first three postoperative months before leveling off. These risks stem from restricted body awareness, limited adherence to weight-bearing guidelines, leading to microtraumatic stress on the implant and instability, and uncontrolled movements due to spastic paralysis or muscle weakness. Inadequate preoperative measures – such as dislocation prevention training, appropriate movement instruction, or orthopaedic aids – further increase instability and hinder rehabilitation. Therefore, the indication for surgery must be carefully evaluated, and patients should receive counseling on fall prophylaxis, secure positioning, and partial weight-bearing challenges, particularly early postoperatively.