Primary knee replacement for primary osteoarthritis in the aged: gender differences in epidemiology and preoperative clinical state.

BACKGROUND AND AIMS: The purpose of this study was to calculate the incidence of primary knee replacements for osteoarthritis (OA) and to compare preoperative clinical situation between men and women aged ≥80 years. Patients aged 75-79 formed a comparison group.

METHODS: We retrospectively reviewed a population-based series of 1396 primary knee replacements performed due to primary OA in a joint replacement hospital between 2002 and 2008. Preoperative clinical data were recorded prospectively into a joint replacement database. Data on preoperative clinical situation (e.g. deformities, mobility level and clinical knee scores) was compared between the age groups, and between genders within both age groups.

RESULTS: The incidence of primary knee replacements performed due to OA in patients aged ≥80 years increased from 553/100,000 in 2003 to 785/100,000 in 2007. After adjustment for age, gender, anesthesiological risk score and laterality of OA, both age of ≥80 years and female gender were associated with higher probability of using walking aids and inability to climb stairs. Age but not gender was associated with walking distance and presence of severe axial deformity and severe antero-posterior instability. Female gender but not age showed association with pain, medio-lateral instability and poor preoperative clinical knee scores.

CONCLUSIONS: Patients aged ≥80 years and particularly women present with higher mobility restriction and more progressed OA at the time of primary knee replacement. Barriers restricting access to surgery should be identified and removed to improve the care of older patients with severe knee OA.