TKAs are a common, safe and effective procedure. However, some healthcare providers may be averse to offer TKAs in patients aged above 80 due to concerns of higher risk of surgery as well as patient survivorship. Many studies in different specialties have shown the pervasiveness of ageism in healthcare systems around the world resulting in poorer patient outcomes[17–21]. With better healthcare and longer average life expectancy[22], we can anticipate more and more healthy and active elderly who would benefit from the improved function that TKAs can provide. Here we have shown that TKAs are safe and effective in the octogenarian population with comparable rate of revision and post-operative outcome. To the authors’ best knowledge, this was the first study to investigate the long-term results of TKA in octogenarian.
In terms of implant survival, our study correlates with Klasan et al., who looked at the medium-term outcomes of TKAs in octogenarians in Australia[23]. Implant survivorship at 10 years was reported at 99.5%, and patient survivorship was 26% at 10 years; mean follow-up was 7.76 years. Joshi[15] reported a 10-year patient survival of 34% in octogenarian TKAs in 2003. Our study observed a 10-year implant and patient survivorship of 100% and 54.6% respectively. As expected, the elderly enjoyed excellent implant survival but had poorer patient survival. The difference in patient survival between our study and Klasan’s may be explained by our higher life expectancy than Australia[24].
Tay et al.[25] found the 2-year revision rate was higher in octogenarians (2.9% vs 1.4%), but this was not statistically significant (p = 0.31). Klasan[23] reported a revision rate of 0.46% (versus 1.55% in younger patients, p = 0.51) with mean follow-up of 7.76 years. The lower rate of revision is likely due to lower functional demand and higher threshold for performing revision arthroplasty in the elderly. In our study, the rate of revision was comparable to the younger cohort; only 1 patient in the control group required revision TKA, which may be due to smaller sample size.
Multiple studies have shown a correlation between advanced age with increasing LOS[25, 26]. Tay et al. reported a mean LOS of 6.3 vs 5.4 days in octogenarian vs younger cohort. Austin et al. reported a mean LOS of 3.30 vs 2.91 days, with 37% requiring facility discharge. In comparison, our LOS was 9.55 ± 3.28 vs 9.23 ± 3.19 days (octogenarian vs control), with 87% discharged to convalescent hospital. This is likely due to old practice; with introduction of newer surgical practice and accelerated rehabilitation protocols[27], most our patients currently have shorter length of stay and are discharged home directly.
Yohe et al. studied the complication rate of octogenarians according to the American College of Surgeons National Surgical Quality Improvement Project (ACS-NSQIP) database in USA[28]. Rate of major complications such as stroke, myocardial infarction, sepsis and revision surgery was found to be 3.5%, with overall rate of revision 1.2%. 4.7% patients presented with unplanned readmissions within 30 days. In comparison, our rate of major complications in octogenarian was 4.5%, and revision rate was 0%. The slightly higher complication rate and difference in rate of revision may be due to small sample size or overall low TKA volume at our hospital. We report a high minor complication rate in our study (28.3%), with a majority due to deep vein thrombosis (DVT). This is due to the lack of modern multi-modal DVT prophylaxis such as early mobilisation, thromboembolism-deterrent stockings, sequential compression devices and direct oral anticoagulants which are now routine in our unit. Overall mortality rate in Yohe’s study was found to be 0.3%, which was increased in patients with dependent functional status and ASA > 2 (OR 8.94 and 6.11 respectively). This was comparable with our findings of 0%.
Cher et al. studied the functional scoring between octogenarians and younger patients in TKA at 6 and 24 months[29]. Both groups showed statistical improvement in KSS and KFS post-operatively. In the octogenarian group, mean KSS improved from 36.77 to 84.44 (p < 0.05), while mean KFS improved from 39.50 to 55.77 (p < 0.05). In our study, mean KSS in octogenarian improved from 34.48 to 94.22 (p < 0.01) which was comparable. This improvement was maintained during the lifetime of the prosthesis as well as the patient. KFS in our study was not significantly improved, this may be due to deterioration in our patients’ overall ambulatory status with longer follow-up and increasing age.
There are limitations in our study. This study was retrospective in nature; octogenarians with poor premorbid status and deemed surgically unfit would naturally not be included. There would also be inherent bias from healthcare providers and relatives to opt for a more conservative management in marginal patients. Using revision as an end-point for TKA survivorship in these patients may therefore underestimate the true figure. In this study, our control group was chosen to be aged between 70 to 80. This was intentionally done to provide a more comparable cohort to the above-80 group. We would anticipate a larger difference in pre-operative functional score, post-op improvement as well as complication rate with a control group that included all ages. Our moderate sample size of 67 patients at a single centre may also affect the power of our study. This study was performed more than a decade ago; evolving surgical methods, different surgeons as well as introduction of multi-disciplinary approach to accelerated TKA rehabilitation may also introduce heterogeneity between earlier and later cases in our study.
Here we have shown that TKA in octogenarian has similar complication rate and functional outcome compared to a younger age group. Despite the higher ASA grading overall, post-operative complications were comparable to those aged between 70–80 years old. While there was a lower patient survivorship in the elderly group due to age difference, implant survivorship was comparable. Function score remains poor in octogenarian without significant difference in comparison to the younger cohort; this is to be expected as they often have impaired muscle strength, coordination and balance. However, patients are still able to benefit from TKA with improved knee range of movement and pain which is reflected in KSS. Clear surgical objective, addressing patients’ concern and expectation is paramount in order to achieve good outcome following TKA.