Frailty index is associated with periprosthetic fracture and mortality after total knee arthroplasty

This cohort study of adult (≥50 years) patients aimed to calculate a validated, preoperative frailty deficit index (FI) and used it to compare outcomes following total knee arthroplasty (TKA), primary and revision, from 2005 through 2016. Using multivariable logistic and Cox regression, the authors analyzed whether FI, adjusted for age, predicts outcomes prior to hospital discharge, within 90 days, and within 365 days. They classified 9818 patients undergoing TKA (7920 primary and 1898 revision; median age, 69 years) as frail (21%), vulnerable (39%), and non-frail (40%). Frail, relative to non-frail, patients were more often female with more systemic diseases (American Society of Anesthesiologists classification, ≥III). While in-hospital, frail patients were found to have increased odds of reoperation (odds ratio, 2.52) and wound complications/hematoma (odds ratio, 2.15). Within 90 days, there was increased risk for periprosthetic fracture (>4-fold) and mortality (>9-fold) following TKA after age adjustment. Within the first year, frail patients were at heightened risk for death (hazard ratio, 8.08), any patient infection (hazard ratio, 1.97), wound complications/hematoma (hazard ratio, 2.16), periprosthetic fracture (hazard ratio, 3.03), and reoperation (hazard ratio, 1.41). At no time point were significant associations found with arthrofibrosis, aseptic loosening, or patellar clunk syndrome. One-fifth of patients undergoing primary and revision TKAs are frail and at notable risk for complications. Calculating a preoperative FI should guide pre-habilitation efforts (eg, chronic disease management, wellness) before and postoperative surveillance after TKA.