How Do Outcomes Compare in Younger Versus Older Revision TKA Patients?
Dr. James Keeney answers ICJR’s questions about a study in which he and his colleagues evaluated preoperative surgical indications, timing of the aseptic revision, and outcomes of revision total knee arthroplasty in younger patients compared with older patients.
ICJR: What questions did you and your co-authors want to answer with this study?
James A. Keeney, MD: The incidence of primary and revision total knee arthroplasty (TKA) in younger patients have been increasing over the past 2 decades. Understanding why this unique patient group is undergoing revision TKA and what outcomes they are experiencing may help to improve preoperative optimization, intraoperative techniques, and perioperative care to enhance long-term success of aseptic revision TKA.
I was involved in a study evaluating the outcomes of revision TKA among younger patients (under age 55) at another institution.  That study identified inferior clinical performance and a high reoperation rate among 81 revision TKAs. However, the comparative cohort consisted of 81 matched patients who had undergone primary TKA, not revision TKA. In addition, the procedures were performed between 1996 and 2008, before preoperative optimization was routinely done.
Our goal with the present study was to help characterize preoperative surgical indications, timing of the aseptic revision TKA, and outcomes of revision TKA in younger patients. We wanted to determine if a more contemporary group of younger revision TKA patients would experience outcomes similar to those of the earlier study or if more recent practice would result in improved outcomes.
Instead of comparing revision and primary TKA outcomes in younger patients, our intention was to evaluate relationships between younger patient age and outcomes of aseptic revision TKA.
ICJR: What did you conclude from this study?
Dr. Keeney: We had several important observations:
- Younger patients (age 55 or younger) present for aseptic revision surgery sooner after index primary knee replacement than the more-traditional 60- to 75-year-old age group, without major differences in surgical indications other than less-frequent indications for polyethylene wear or component loosening.
- Younger patients were nearly twice as likely to undergo early reoperation after aseptic revision TKA than older patients, with the 3 most common re-revision indications – infection, stiffness, and extensor mechanism failure – occurring in 20% of younger patients.
- Younger patients had a 1.7-fold higher incidence of tobacco use disorder than older patients.
- Although above-knee amputation was a relatively rare complication, it was more than 12 times more common in younger than in older patients.
ICJR: How did you reach your conclusions? What was your study cohort and what did you find with your analysis?
Dr. Keeney: For this study, we chose to compare the outcomes of first-time aseptic revision TKA in a cohort of younger patients with those of an older patient group:
- 158 revision TKAs in patients age 55 or younger
- 300 revision TKAs in patients age 60 to 75
We excluded patients between ages 56 and 59 to create 2 distinct patient groups, minimizing the potential for demographic overlap. In the published literature, 2 different ages – 55 and 60 – have been used to characterize younger primary TKA patients, which can confound the conclusions made about younger patients.
A detailed medical chart review was performed for all patients to identify:
- Preoperative indications for revision TKA
- Timing between the index procedure and the revision
- Demographic features
- Medical comorbidities
- Surgical techniques
- Postoperative outcomes, including reoperations, component revisions, and indications for additional surgical procedures
Statistical assessments included conventional univariate analysis and a 2-sided log-rank test to define 5-year survival estimates and 12-year Kaplan-Meier curves for reoperation and for component re-revision.
The study did not identify significant demographic differences between groups. There was a significant difference in medical comorbidities, including an understandably higher rate of cardiac disease reported in the older patient cohort (29.3% vs 13.3%) and an unanticipated higher rate of tobacco use disorder among younger patients (44.9% vs 26.3%).
Younger patients were significantly more likely to have undergone early revision TKA (52.5% vs 29.0%) and to have undergone early reoperation for any indication (17.7% vs 9.7%). This contributed to 5-year survival estimates being significantly lower in younger patients for both reoperation (59.4% vs 65.7%) and component re-revision (65.8% vs 80.1%).
ICJR: Why are these findings significant for clinical practice?
Dr. Keeney: We often consider younger patients to be healthier than their older counterparts, but that may not necessarily be the case. As this study suggests, efforts to optimize modifiable risk factors before surgery in younger patients are as important as they are in older patients.
In the absence of purposefully engaged preoperative optimization for TKA revision patients, the rate of revision surgery in this study, which included patients who had undergone revisions between 2011 and 2018, was not substantially different than the rate reported at another institution, where the revision procedures had been performed between 1996 and 2008.  The similarity in reoperations across this period suggests that aseptic TKA outcomes in younger patients may be more influenced by preoperative and perioperative management than by implant technology or advancements in surgical technique.
Preoperative medical optimization pathways have been in a process of development and implementation over the past decade, and the association of medical risk factors with adverse postoperative outcomes has been more extensively assessed for primary TKA than for revision TKA. Although the present study cannot attribute causation, the potential association of severe adverse outcomes in this younger patient cohort with a high prevalence of tobacco use disorder supports active engagement of smoking cessation before aseptic revision TKA.
Purposeful engagement of medical optimization for primary TKA has occurred in our institution for several years. This study has heightened our awareness of the need to engage this process for aseptic revision TKA patients, as well. We suggest that this may be important for other surgeons to consider and for other investigators to help validate.
Walker-Santiago R, Tegethoff J, Aggarwal A, Keeney JA. Young patients have high early reoperation and revision rates after first-time aseptic revision total knee arthroplasty (Paper 732). Presented at the 2021 Annual Meeting of the American Academy of Orthopaedic Surgeons, August 31-September 3, San Diego, California.
Walker-Santiago R, Tegethoff JD, Ralston WM, Keeney JA. Revision total knee arthroplasty in young patients: higher early reoperation and rerevision. J Arthroplasty. 2021 Feb;36(2):653-656. doi: 10.1016/j.arth.2020.08.052. Epub 2020 Aug 31.
About the Expert
James A. Keeney, MD, is Division Chief, Adult Reconstruction, and an Associate Professor of Clinical Orthopaedic Surgery with MU Health Care and the Missouri Orthopaedic Institute, Columbia, Missouri.
Disclosures: Dr. Keeney has disclosed that he is a paid consultant for DePuy Synthes, Flexion Therapeutics, and Heron Therapeutics.
- Stambough JB, Clohisy JC, Barrack RL, Nunley RM, Keeney JA. Increased risk of failure following revision total knee replacement in patients aged 55 years and younger. Bone Joint J. 2014 Dec;96-B(12):1657-62.