Concerns regarding increased loosening rates and the potential need for multiple revision surgeries have traditionally discouraged younger patients from undergoing TKA. Non operative management as well as other less invasive surgical options, such as arthroscopic debridement and proximal tibial osteotomy, may be considered in patients with specific indications, such as uni-compartmental disease and limb malalignment. However, clinical improvement after knee arthroscopy in the arthritic knee tends to decline over time, whereas patients who undergo TKA after tibial osteotomy may be at higher risk of complications. In addition, delaying TKA surgery is probably not a realistic option when patients continue to experience prolonged pain and increasing disability in performing daily recreational or professional activities, despite routine non operative management. It has been argued that worse outcomes are to be expected when prolonged periods of morbidity have preceded TKA, particularly in achieving a higher level of function.

Over the last decades, satisfactory outcomes have been reported in terms of success rates and implant survival in younger patients undergoing TKA. Gill et al. [7] found a 96.5 % survival rate at 18 years (including patients with osteoarthritis −51.4 %, with rheumatoid arthritis −40.3 % and with other diagnoses −8.3 %). Diduch et al. [8] calculated a survival rate of 87–94 % at 18 years in a mixed population with idiopathic and post-traumatic osteoarthritis. Dalury et al. [9] also found, at an average of 7.2 years follow up, comparable success rates between TKA patients younger than 45 years and those older. However, when patient reported outcomes are considered, findings tend to be more diverse. Self reported outcomes are increasingly thought to better express the success rates of TKA as they incorporate the patient’s perspective. In a study of patient reported outcomes after TKA, Williams et al. [10] found comparative Oxford knee and EuroQol scores across different age groups but with a linear trend towards improved outcomes with decreasing age. Interestingly though, a higher dissatisfaction rate was found in patients aged <55 years. The authors suggested that higher activity expectations may differentiate subjective from objective outcomes in younger patient groups. In a recent multi-center study, Parvizi et al. [11] found that approximately one third of young patients who underwent TKA reported residual symptoms and limitations in activity. In line with these findings, Nilsdotter et al. [6] confirmed a decrease in daily living activity scores at 5 years after TKA without however identifying a predictive effect of age on this finding. Interestingly, in a recent survey among young TKA patients (average age 54 years), Barrack et al. [3] found that socioeconomic factors were more strongly associated with satisfaction and functional outcomes than demographic or implant factors. Specifically, low income and minority patients were more likely to be dissatisfied and have functional limitations after TKA.

Despite an increase in life expectancy and advances in medical treatment the chronological age limit for patients undergoing TKA, among other elective major orthopaedic procedures, remains controversial. Elderly patients have been found to be less likely but equally willing to receive a TKA compared with their younger counterparts [12]. Concerns have been raised regarding the incidence of morbidity and post-operative mortality, with increasing age, in patients undergoing TKA. Elderly patients are considered to suffer from more medical comorbidities pre-operatively and more postoperative complications. A higher likelihood of blood transfusion has also been found in this group of patients [13]. In addition, elderly patients receiving TKA are more likely to be transferred to a rehabilitation facility postoperatively [5]. Most recently, Yoshihara et al. [14] reviewed medical files of US patients aged 80 years and older who underwent TKA between 2000 and 2009. They found an increasing incidence of TKA in this age group as well as an increased number of comorbid conditions suggesting that the indications for surgical treatment have been broadened. The overall in-hospital complication and mortality rates remained stable and decreased over time respectively. However, both parameters were significantly higher compared to patients aged 65–79 years [14]. Similar findings were confirmed by other investigators [15, 16]. These findings indicate that careful patient selection based on surgical indications and aggressive postoperative treatment are essential for achieving optimal outcomes. Patients in these age groups should be informed of the higher risk involved. Whereas higher rates of medical morbidity and post operatively mortality are a concern in the elderly population, clinical outcomes have been encouraging. Berend et al. [17] recorded significant improvements in pain and Knee Society scores in TKA patients older than 89 and a higher survival rate than in age matched controls. In their cohort of nonagenarians receiving TKA, Alfonso et al. [13] found significant pain reduction and slightly higher functional capacity and better survival characteristics compared to age matched controls at a mean follow up of 4.1 years. As expected, most studies of this kind are limited by their short follow up. Overall, these findings suggest that advanced age should not present a contraindication for TKA.