The analysis of results of knee arthroplasty performed in two groups of patients - 40 patients of senile age and 40 long-livers, taking into account their comorbidity was perfomed. Patients with the Charlson comorbidity index of 5-8 points, subject to hospitalization on the profile for pre-examination and inpatient treatment of aggravating somatic pathology, as preparation for a future knee replacement surgery. Results after the operation in the groups on the scale KOOS was 78±8,18 and 76±11,36, and according to WOMAC 142±4,6 and 151±4,8, respectively. A year after the operation, there were no statistically significant differences between two groups. Operative intervention is possible only if its risk is minimized.