THA: Results in the Very Elderly
There have been a number of publications specifically evaluating the success of hip arthroplasty in the very elderly. Whereas most outcome studies in joint arthroplasty focus on the mid-term or long-term surgical results in an attempt to demonstrate the successful longevity of an implant, studies of the elderly tend to focus on the short-term functional improvements, morbidity and mortality to demonstrate safety.
THA Reduces Pain & Improves Function in the Very Elderly
Studies reporting on the results of THA in the very elderly are generally encouraging, demonstrating the patients' ability to return to age-appropriate activity levels. Even in patients over the age of 90 years, implantation of a THA can significantly improve the quality of life, while allowing for the maintenance of independent ambulation and living. Several authors suggest that in addition to providing substantial improvements in quality of life, THA in the very elderly may also be a cost-effective intervention that prevents the need for high levels of assistance and supervision.
Berend et al. reported on 56 THAs in patients who were 89 years of age or older. Pain scores and functional scores improved significantly in their cohort, while the proportion of patients requiring an assist device to ambulate decreased after surgery. Ekelund et al. also reported on THA in very elderly patients. They retrospectively identified 162 patients having a THA at a mean age of 83 years. At 1 year after surgery, 88% of patients available to follow-up had either a good or excellent surgical result. Similarly, in 1995, Levy et al. reported on 100 patients who were at least 80 years old when having a THA. Pain and walking scores increased from an average of 5.1 out of 12 points before surgery to an average of 10.6 out of 12 points after surgery. Additionally, it was found that 96% of the patients were able to live independently at latest follow-up. Pagnano et al. described a 96% satisfaction rate in patients having a hip replacement when older than 90 years, with a 32% increase in patients ambulating with no assist or a cane.
Mortality After THA
Although the perioperative mortality associated with THA increases with age, mortality is a very low-probability event even in the oldest populations undergoing surgery. When combining studies that focused on patients having a THA over the age of 80 years, the rate of perioperative mortality ranges from 0 to 4%. It is important to note that these studies often include nonelective THAs implanted acutely for a fracture, which becomes more common in the older age groups. Therefore, the true mortality rate due to THA after elective surgery for osteoarthritis is likely in the range of 1–2%.
In a report that truly tests the limits of arthroplasty in the very elderly population, Parvizi et al. specifically studied 170 patients over the age of 80 years having a revision hip arthroplasty. Revision hip arthroplasty is associated with a significantly higher operative time and blood loss than primary hip arthroplasty, and would be expected to have a higher associated mortality rate than primary THA. The authors identified only one death (0.59%) within 30 days of surgery, which was equal to the control group of patients under 70 years of age. Unless a very elderly patient has a specific comorbidity that is a cause for significant concern, age alone is not a good reason to overstate the risks of hip arthroplasty.
Morbidity After THA
The medical and surgical complication rate associated with THA is certainly higher in patients that are very elderly. Although these complications are generally amenable to appropriate medical management, it is common for elderly patients to have an extended hospital stay after THA. In an award-winning manuscript, Higuera et al. prospectively followed a cohort of 502 patients older than 65 years having a hip or knee replacement. They found that the complication rate after joint replacement surgery increased 40% through each decade of life, and patients aged 75–84 years were 43% more likely to have a complication than those aged 65–74 years (p = 0.002).
The Mayo Clinic's experience with hip replacements in patients 90 years of age or older includes 65 patients from 1970 to 1997. They describe a 46% rate of complications after primary THA, with transient postoperative confusion and urinary tract infection or retention accounting for the majority of complications. They found that serious medical complications associated with primary THA, such as cardiac and pulmonary complications, were less likely, accounting for nine events in 47 patients. Despite these more serious complications, only one patient died from a myocardial infarction perioperatively.
When including all reports on morbidity after THA in the very elderly, it is clear that although the medical complication rate is higher than that associated with younger age groups, the very elderly rarely suffer an event that has long-standing effects on their quality of life. Instead, this increase in perioperative morbidity is manifested as an increase in the length of hospital stay. Thus, although increased morbidity should be anticipated in this patient population, most events are treatable medical issues without long-term effect and should not preclude surgical intervention in the very elderly.