According to the findings presented here, the postoperative functional outcomes were significantly lower for the senile age group compared with the elderly age group. Furthermore, the revision rate of UKA in the senile was similar or less than those of the elderly patients. Thus, the findings of this study supported that the UKA was an excellent choice for the senile patients who meet the criteria of isolated single compartment osteoarthritis, as it possesses both high levels of safety and efficacy.
The literatures demonstrated that UKA had a growing number of advantages compared to TKA in the treatment of unicompartmental osteoarthritis, including faster recovery, shorter hospital stay, better satisfaction and fewer perioperative complications [20, 21].With the increasing elderly population and longer life expectancy, the majority of eldrely patients, particularly those who were senile, suffered from chronic medical diseases and had a weaked physique, such as heart disease and respiratory disease, among others .As a result, it was particularly vital to alleviate pain and dysfunction in patients with osteoarthritis through a minimally invasive procedure.
The KSS and OKS were reliable indexes for assessing knee function recovery after arthroplasty, and a sdudy concluded that age was a significant predictor of the function at follow-up . As shown in Figs. 2, the KSS functional outcome in advanced patients (> 75years) was lower than in younger patients after UKA. On the other hand, the OKS, which indicated that scores were adversely correlated with functional outcomes, was lower in the senile patients compared the elderly. It was contradictory with our previous outcomes. There was a possibility that the OKS included a total of 12 items, 5 of which focused on knee pain. And the senile patients had a greater capacity for enduring pain. Alternately, they were sensitive to easing the pain after procedure because they had been through a lot of it .Overall, the decline in functional results were associated with older age, the existence of possible comorbidities and the decrease in behavior and physiology.
Revision, which is defined as the removal or exchange of at least one implant component in the knee for any reason, was often regarded as a endpoint of UKA survival . Apart from functional outcomes, our analysis indicate that the revision rate of UKA in senile patients was comparable or less than those of younger patients. Age should not be considered a direct determinant in the revision or the decision to do TKA or UKA, but there was a potential effect on morbidity and mortality in the older group.
A growing body of research indicated that the most common reasons for UKA revision were bearing dislocation, aseptic loosening, and contralateral arthritis progression, all of which were related to implant design, surgeon experience, and hospital volume [26, 27]. And, some studies also found that the risk of perioperative death in TKA increased with age and history of cardiovascular disease [28, 29]. In our study, senile patients who underwent UKA showed excellent clinical results and lower revision rate during follow-up. In the meantime, it was obvious that the life expectancy of the senile patients was relatively short, and the implants were less likely to be exceeded.
The following were the limitations of this analysis. Firstly, several studies tended to utilize > 80 years as the cut-off for senile age. This could lead to the omission of data on those patients. In addition, despite the fact that included studies were published in influential journals, there were differences in demographics and operation techniques between countries and regions.Thirdly, there was no mention of medial or lateral UKA in the study and report on implant types like mobile and fixed bearing. Fixed bearings had more polyethyene wear compared with mobile bearings, according to the literature. Furthermore, despite the fact that functional outcomes, revision rate and survival rate all were reported, the length of follow-up varied between studies. In our annlysis,one study had repoted the shortest follow-up of 1.8 years, while another was followed for 8.3 years. Finally, there were potential confounders, including BMI, activity leveal,sex and comorbidities.