Effect of neurodegenerative comorbidities on the risk of revision of knee joint replacements

Background: As populations age, both joint arthroplasty procedures and neurodegenerative diseases like Parkinson's disease (PD) are increasingly common. While general risk factors for knee prosthesis failure are well known, the specific impact of PD on implant survival is less clear. Motor symptoms of PD—rigidity, bradykinesia, postural instability—could impair joint function and raise complication risks. Understanding this relationship is crucial for optimizing care in these patients. Aim: This study investigated whether patients with preoperative PD have a greater risk of revision after total knee arthroplasty (TKA). Secondary aims included determining causes of failure, comparing outcomes with total hip arthroplasty (THA), and assessing biomechanical factors through computer modeling. Materials and Methods: A retrospective cohort analysis was conducted using the Emilia-Romagna Joint Replacement Registry (RIPO) and administrative databases. Patients with PD who underwent TKA from 2003–2018 were compared to matched controls without neurodegenerative diseases. The primary endpoint was revision for any reason. Kaplan–Meier survival analysis and multivariate Cox regression were applied. THA outcomes were analyzed in parallel, and biomechanical modeling was performed to simulate joint forces in PD. Results: Of 52,573 TKAs, 551 were in PD patients. The revision rate was significantly higher in the PD group (8.4% vs. 3.5%), with a 2.7-fold increased risk (HR 2.7; 95% CI 2.1–3.7). Septic loosening and implant dislocation were more common in PD patients, while aseptic loosening rates were similar. For THA, long-term revision rates did not differ, but PD patients had more early complications, notably periprosthetic fractures. Biomechanical modeling showed no significant differences in joint loading. Conclusions: Parkinson’s disease independently increases the risk of TKA failure, primarily due to systemic frailty, infection, trauma and not mechanical overload. Tailored perioperative and multidisciplinary approaches are needed to improve outcomes in this population.