Functional gain following knee replacement in patients aged 75 and older: a prospective follow-up study

The aim of this prospective follow-up study was to analyze which patient characteristics predict better functional ability, as well as improvement in the ability, following knee replacement in the aged. The focus was on the impact of specific comorbidities and radiologic data.

Knee osteoarthritis patients aged ≥75 years (n = 167) scheduled for knee replacement answered to a questionnaire asking about performance in the activities of daily living (ADL) before the operation, and 1 year afterwards. Radiologic data were evaluated from the latest radiographs, and comorbidity data from patient records. The primary outcome was a sum score indicating how many ADLs (out of 10) the patient was able to perform without difficulty. The factors associated with ADL performance were analyzed with adjustment for age, gender, Charlson's comorbidity index and Kellgren-Lawrence score.

Knee replacement resulted in improved performance in almost all the analyzed ADL activities. Except for cardiac diseases, the effect of the analyzed comorbidities on ADL performance was not significant. Older patients and women attained lower final functional ability than younger patients and men, but improved similarly. In more progressed osteoarthritis, the final ability was lower, but the improvement gained was greater.

Comorbidity, age, or more progressed osteoarthritis should not be considered an impediment to knee replacement. Even though the final functional ability may be lower in some, the improvement gained by surgery is similar regardless of comorbidity, and was more pronounced in more progressed disease.