The lifetime risk of revision following total knee arthroplasty

Abstract

Aims The success of total knee arthroplasty (TKA) is usually measured using functional outcome scores and revision-free survivorship. However, reporting the lifetime risk of revision may be more meaningful to patients when gauging risks, especially in younger patients. We aimed to assess the lifetime risk of revision for patients in different age categories at the time of undergoing primary TKA. Methods The New Zealand Joint Registry database was used to obtain revision rates, mortality, and the indications for revision for all primary TKAs performed during an 18-year period between January 1999 and December 2016. Patients were stratified into age groups at the time of the initial TKA, and the lifetime risk of revision was calculated according to age, sex, and the American Society of Anesthesiologists (ASA) grade. The most common indications for revision were also analyzed for each age group. Results The overall ten-year survival rate was 95.6%. This was lowest in the youngest age group (between 46 and 50 years) and increased sequentially with increasing age. The lifetime risk of requiring revision was 22.4% in those aged between 46 and 50 years at the time of the initial surgery, and decreased linearly with increasing age to 1.15% in those aged between 90 and 95 years at the time of surgery. Higher ASA grades were associated with increased lifetime risk of revision in all age groups. The three commonest indications for revision were aseptic loosening, infection, and unexplained pain. Young males, aged between 46 and 50 years, had the highest lifetime risk of revision (25.2%). Conclusion Lifetime risk of revision may be a more meaningful measure of outcome than implant survival at defined time periods when counselling patients prior to TKA. This study highlights the considerably higher lifetime risk of revision surgery for all indications, including infection, in younger male patients. Cite this article: Bone Joint J 2022;104-B(2):235–241.

The lifetime revision risk of unicompartmental knee arthroplasty

“…33,37 The difference in incidence between the procedures may be linked to surgical factors (TKA is more invasive), and differences between patient cohorts: generally TKA patients have more comorbidities, 6,9 which are risk factors for PJI. 38 While young males (aged 46 to 50 years) had the highest lifetime risk of revision for TKA (25%), 13 this was still lower than the lifetime risk of revision for UKA in this group (37%). A better understanding of optimal patient selection for UKA and TKA may therefore have implications for both cost-effectiveness and post-surgical patient outcomes.…”

“…There was a trend of Thelifetimeriskofrequiringarevisionunicompartmental(UKA)ortotalkneearthroplasty(TKA)a)overallandb)stratifiedbyageandsex.The closedcirclesrepresentlifetimeriskofrevisionestimatesforUKA,andthesquaresrepresentestimatesforTKA.Barsrepresent95%confidence intervals. TKA estimates are from Stone et al 13 decreasing time to failure with increasing age at primary surgery (Supplementary Figure a).…”

“…As all revision surgery is captured by the NZJR and linked to primary procedures, lifetime risk of revision can be directly calculated. 12,13 The incidence rates of all-cause revision surgery were calculated by dividing the count of revision events by cumulative time with the primary implant. Implant survival time was censored by mortality.…”

“…11 The main benefit of a lifetime risk estimate is that it is easy to explain to a broad audience and is more informative of the magnitude of the risk of revision, as it is calculated over a patient's lifetime rather than at a defined time period. 12,13 This can aid understanding of the risk of revision associated with arthroplasty.…”

“…We previously reported the lifetime risk of revision for total knee arthroplasty (TKA). 13 We now aim to determine the lifetime risk of revision for UKA, with respect to key patient demographic data and reasons for revision, and to compare these to TKA.…”