The impact of frailty on outcomes following hip and knee arthroplasty

Abstract

Aim: The broad aim of this thesis was to investigate the impact of frailty on outcomes following total hip and knee arthroplasty (THA and TKA). The outcomes considered were short-term mortality, patient-reported outcomes (PROMs) and frailty trajectories. Methods: Databases of primary and secondary care electronic medical records from England and linked mortality records were used. Frailty was assessed using the validated electronic frailty index (eFI) and categorised as fit (eFI≤0.12), mild (0.120.36). PROMs were assessed using the Oxford hip and knee scores (OHS and OKS) and patient-reported success. The association between frailty and (i) short-term mortality and (ii) PROMs following THA and TKA were assessed using multivariable regression models, with year of birth, sex, year of surgery, and quintile of index of multiple deprivation included as covariates. The rate of change in eFI in the period up to two years before THA and TKA and up to two years after THA and TKA was assessed using random effects models with linear splines. Results: Increasing frailty was associated with increasing 30-day mortality following THA and TKA in a multivariable model. Crude 30-day mortality following THA and TKA, respectively increased from 0.25% and 0.16% among those who were fit to 0.85% and 0.44% among those with severe frailty. Increasing frailty was also associated with lower postoperative OHS and OKS (indicating worse outcomes) in a multivariable model, which persisted after adjustment for preoperative score. Patient-reported success following hip and knee arthroplasty, respectively decreased from 97% and 93% among fit individuals to 90% and 83% among those with severe frailty. The association between increasing frailty and reduced likelihood of patient-reported success persisted in a multivariable model. In a multivariable random effects model, the rate of increase in the eFI (95% CI) in the period before THA and TKA, respectively was 0.025 (0.024, 0.025) and 0.025 (0.025, 0.025) units per year. The rate of increase in the eFI in the period after THA and TKA, respectively was statistically significantly lower than the preoperative increase, by -0.0036 (-0.0041, -0.0032) and -0.0030 (-0.0034, -0.0026) units per year. Conclusion: Frailty was associated with higher short-term mortality and poorer PROMs following THA and TKA. However, even among those with severe frailty, crude 30-day mortality following THA and TKA was less than 1% and more than 80% of patients reported a successful outcome. The results are consistent with a modest beneficial impact of THA and TKA on the rate of progression of frailty.

Date of Award	1 Aug 2023
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Terence O'Neill (Supervisor) & Mark Lunt (Supervisor)