Risk factors for post-operative complications in patients older than 80 years treated surgically for periprosthetic distal femoral fractures after total knee arthroplasty

Periprosthetic distal femoral fractures after total knee arthroplasty (TKAPF) are challenging in very elderly patients. This study aimed to identify the incidence and risk factors for post-operative complications in patients aged over 80 years surgically treated for these fractures. A multicentre SOFCOT database (2012-2019) was analyzed. Patients aged >80 years with TKAPF were compared to a <80 control group. Outcomes included complications, reoperation, mortality, and operative delay. Multivariable logistic regression was used to identify independent risk factors for reoperation and mortality. Among 376 patients aged >80 (mean age 87.5 ± 4.4 years; 87.5% female), 359 patients (95.5%) were surgically treated, the reoperation rate was 10.0%, the complication rate was 19.5%, and mortality at two-year follow-up reached 29.5%. Mortality was independently associated with ASA score (p = 0.0096), but not with age, fracture pattern, or surgical approach. Operative delay (mean 2.9 days) had no impact on mortality or reoperation but was associated with more infections and implant loosening (p<0.001). In patients over 80 years, systemic frailty, reflected by ASA score, was the main determinant of mortality, while delayed surgery (>72h) increased local complications, supporting an individualized surgical approach, based on general conditions rather than fracture morphology or surgical preference.