- Top of page
- MATERIALS AND METHODS
- AUTHOR CONTRIBUTIONS
Aging is inevitable, as are problems with organ failure such as osteoarthritis and consequences of frailty such as osteoporotic hip fractures. From a musculoskeletal specialist's perspective, these are 2 major causes of disability among the older age group.
Centenarians are individuals who have avoided or delayed various diseases that lead to death in the first 100 years of life and are a living example of successful aging (1). Even though ∼40% of centenarians are functionally independent (1), they are among those at the highest risk for both disabling arthritis and osteoporotic fractures. Arthroplasty is effective but is a treatment of last resort for these musculoskeletal problems. However, with increasing age, the safety and desirability of performing such expensive and invasive procedures may be questioned for 2 reasons. The first reason is the utilitarian view that finite health care resources should be spent on individuals in which the potential benefits are highest. Thus, older individuals with fewer potential remaining years of life are less “deserving” of expensive “investment” than younger persons. The second reason is biomedical. Arthroplasty may be too hazardous for the older patient due to frailty, defined as a combination of inability to deal with physical and psychological stress and physical impairment. With respect to arthroplasties, however, there are comparatively few data that inform the above debate. Due to the relative rarity of centenarians and arthroplasties among them, such data are more likely to emerge from very large, nationally representative databases than from single-site or multicenter studies. In this report, we provide such data on the utilization and short-term outcomes of arthroplasties among the oldest age group in the US.
- Top of page
- MATERIALS AND METHODS
- AUTHOR CONTRIBUTIONS
There have been few studies on arthroplasty among nonagenarians and centenarians. Because of the rarity of centenarians and arthroplasty performed on them, previous studies assessing age and arthroplasty grouped all such subjects with those in younger age categories (6–9). Ours is the largest series of primary total hip and knee arthroplasty among centenarians in the published literature. Data from the NIS presented here demonstrate that elective knee and hip arthroplasties are very infrequent medical procedures in this age group.
The postoperative mortality of centenarians, as a proportion of the number of hospitalizations, was lower than the proportion of all-cause mortality for these individuals. This finding probably reflects the selection bias due to channeling of low-risk candidates for arthroplasty. This mortality risk following hip replacement (12%) is several magnitudes higher than the rates (0.26%) reported for all elective knee and hip arthroplasties in the general population (10).
In this study, knee arthroplasty was less frequent than hip arthroplasty. Half of the elective knee replacements were performed for osteoarthritis whereas elective hip arthroplasties were performed primarily for aseptic necrosis and malunion. This relatively low frequency of elective surgery might be due to physician and patient judgment that these individuals are at high risk for poor outcomes and that the risk is not offset by the perceived benefit in light of the relatively short life expectancy (11). The most common indication for hip arthroplasty among centenarians was hip fracture in contrast to osteoarthritis among octogenarians and nonagenarians (9).
Utilitarians such as Callahan (12) have argued that the government should pay only for palliative measures beyond the age of 70 or 80 and not for life-extending measures. By that standard, one may argue that arthroplasty, even though reflecting a one-time expense, is cost effective by increasing patient independence and utilization of ambulatory health care facilities and perhaps even providing cardiovascular health benefits. Indeed medical expenses in the last year of life account for a larger share of Medicare expenditures than in earlier years (13).
Although frailty is known to increase with age, there have been arguments that with better medical care such frailty is being compressed into the extremes of age (14). Centenarians live as long as they do by delaying or even avoiding many age-related diseases. Even among those who live with such diseases for a long time, many appear to do so with better functional status than do younger persons who do not achieve extreme old age. In other words, centenarians are those who have compressed frailty toward the very last few years of their life (15). This could mean that these individuals are at greatest risk for poor surgical outcomes. Alternatively, one could argue that arthroplasty helps centenarians to further postpone and compress the period of morbidity that precedes death.
There are scant data to study the probability of centenarians surviving the immediate postoperative intensive care period after undergoing major surgery such as arthroplasty. A report from the Cedar Sinai Medical Center, Los Angeles demonstrated that surgical intensive care outcomes of 140 nonagenarians were not different from younger patients after adjusting for severity of illness (16). Among centenarians only 2 of 9 hospitalizations ended in the death of the individual (17).
Will centenarians and nonagenarians be able to utilize the benefits from a new hip or knee? The Heidelberg Centenarian Study demonstrated that approximately half of the centenarian population showed moderate to severe cognitive impairment, whereas one-quarter were found to be cognitively intact (18). Furthermore, among those individuals, the age-related cognitive decline decelerated with time, suggesting that centenarians can sustain their mental functioning over time. Another study performed with a cohort of nonagenarians showed that among those surgically treated for hip fractures, being 90 years of age and older did not increase the chance of having a postoperative complication, being placed in a skilled nursing facility at discharge or at 1-year followup, or recovering of prefracture independence in instrumental activities of daily living (19).
Our study's strengths are the nationally representative sample, relatively large number of centenarians, and index procedures and thus robust estimates of in-hospital mortality. Our results are less likely to be biased than single-center reports. In contrast, there are several limitations. Most important is the lack of clinical information about the patient's risk profile, surgical technique, and type of surgeon. Second, in-hospital perioperative mortality may not reflect the overall surgical mortality risk. We did not have out-of-hospital followup data that would have permitted calculation of 28-day, 6-month, and 1-year mortality rates. Another issue is the small number of knee arthroplasties, which makes it difficult to generate estimates of procedure rates among centenarians. From a statistical perspective, the relatively small numbers of procedures compared with the underlying population among centenarians result in a wide confidence interval and therefore the population rates that we have provided should be interpreted as the best estimate and not the actual number of arthroplasties. Last, we relied on the accuracy of the administrative database to assess indications for surgery. Therefore, coding errors could be present in the cause of surgery ICD-9 codes. Age inflation exists in most age databases that rely on census data for their centenarian statistics, including in the US, where a national birth registration system did not exist at the time centenarians were born (20). This is also a potential limitation of our data.
According to the US Department of Census, the number of centenarians could cross the 4 million mark by the year 2050 (21). Over the past decade, the utilization of arthroplasties has been increasing in the US (22), and this trend is likely to continue. Due to the impact of hip fractures, the main indication for hip arthroplasty among centenarians can be considerable. This study provides data that suggest arthroplasty need not be denied to centenarians solely on account of age and the concern of high in-hospital mortality risk.