There is significance differences among different group
White et al.  believes that perioperative education can well improve the postoperative knee flexion, 72% of the patients with good perioperative education can kneel with their affected knees 1 year after the surgery. Our pilot study showed that there were significant differences among these groups. The KSS scores improved as the increase of education level. The majority of patients with poor KSS scores were illiterate patients.
Though the VAS sores of all groups reached good level, the VAS sores of the patients under elementary school degree (group A and group B) had significant different between those above high school degree (group C and group D). Higher education could perform batter.
Poor function is another frequent complaint from patients. The patients in the illiterate group had the worst flexion function in this study, and the proportion of patients with flexion less than 90° in the illiterate group was 8.11%, in which 1 patient finally underwent release surgery. Scientific practices are particularly important for the recovery of postoperative knee extension and flexion function.
Different education may have different performance in rehabilitation
The acceptance of perioperative knowledge, such as eliminating fear, avoiding rough training, controlling training methods and time, and comprehensive pain control, largely depends on the patient's education level .During follow-up, most patients in Group A could not fully understand the rehabilitation program and needed repeated explanations and reminding from the physiotherapists, while patients in Group D could accurately describe the postoperative rehabilitation program and exercise as requested. Many illiterate patients lived in countryside gave up active and passive rehabilitation activities due to pain. While higher education level group patients could communicate or consult with doctors through the WeChat in peaceful moods and have better medical compliances, even if dissatisfied with the outcomes, they could face complication without or less anxiety.
Lower education level patients perform seemed not good
Many patients in the illiterate group and primary school group had poor hearing and vision to read the guide book for rehabilitation, also were not easy to remember the key points of rehabilitation training. Especially the patients aged over 70 who lived in remote areas and had great difficulties in communication, could not obtain the guidance from doctors after discharging because most of them were not capable of using smartphones. These patients were laissez-faire with fear or worry, didn’t act scientific training. Moreover, since young people (their children) worked outside, only patients themselves were at home, which led to the lack of the supervision, the effectiveness of rehabilitation for these patients was often greatly reduced . And as their descriptions of the condition were unclear in smartphone interviews, we have tried a smartphone APP software, by which the range of motion can be measured and automatically sent to the APP through the induction device bound to the ankle of a patient. However, they often gave up the testing due to difficulty in using the smartphone or poor network signal, their pictures and videos for follow-up could only be obtained through other relatives and neighbors. The use rate of this APP by patients with junior high school education or above was relatively higher, but soon they ceased because of expensive medical costs.
Higher education level patients perform seemed better
Patients with high school education or above were good at comprehending the goals in rehabilitation, and their compliance were significantly higher than that of other groups. While most patients in high school education and above group lived in cities, accompanied by their young children, the postoperative rehabilitation of those patients was effective, their follow-ups were more regular than other groups, only 2 patients with poor function (which accounted for 1.74%, it is far lower than that in the other three groups). Education level also shows advantages in postoperative knee extension function, optimizing pre-operative TKR education were helpful to improve outcomes of total knee arthroplasty.
Education level is an independent factor affecting the rehabilitation of TAK
Enhanced rehabilitation programs (ERPs) was developed based on the ERP principles presented by Kehlet , which normally include in-depth preoperative patient education (PPE) . PPE received by patients can effectively increase WOMAC score and Eq-5D-5L Health Status Index 1 year after knee and hip arthroplasty [12, 22]. The more knowledge of surgical procedures and rehabilitation procedures the patients get, the better their rehabilitation outcome the patients would achieve after discharge . However, the degree of knowledge and information that patients with total knee arthroplasty or total hip arthroplasty obtain from a PPE session partly depends on the self-education level of the patients.
It is a common sense that education level is an independent affection factor for self-efficacy in rehabilitation after total knee arthroplasty . Even some researchers hold negative views, Sun et al.  divided patients of tumor into two groups based on education level: junior high school group and high school above group, it was found that education level was not an influencing factor on function after tumor-type prosthesis replacement in patients (only 20 Cases) with knee osteosarcoma. Ding et al. [25, 26] analyzed the education levels of 96 patients with unilateral total knee arthroplasty and revealed that education level was not an independent risk factor, but medical compliance, which was closely related to education level, was an independent risk factor. It was also confirmed by A’bulaiti et al.  that treatment compliance, which was closely related to education level, was an independent risk factor affecting joint function, and the medical compliance was as high as 86.59% in the highly-educated group (HSS score ≥ 70). Yao et al.  grouped total knee arthroplasty patients based on two educational levels: below junior high school (31 Cases) and above high school (64 Cases), and they found out a significant difference between the two groups in self-efficacy scores (P < 0.05), which demonstrated that education level is an independent risk factor affecting the rehabilitation after knee arthroplasty.
Different classification of education level maybe the cause of this contradictory, diversified education level classifications appeared in recent literatures . Cavanaugh et al.  divided the education level of patients into four groups: less than high school, high school diploma or general educational development, some college or vocational training, and baccalaureate or about, in his study, there were no elementary group and illiterate group, and only 2.9% of the people with low education, which was quite different from our grouping for this study. Anderson  divided the patients into multiple levels in combination with local patients’ education: illiterate, undergraduate degree, postgraduate degree and so on, the number of patients with university and postgraduate education in this study is too small to be suitable for grouping. Pua et al.  divided patients into four groups according to local education status: illiteracy, primary education level, secondary education level, and tertiary education level, when the knee pain and walking limitations of patients 6 months after surgery were observed, it was found that differences occurred under this classification. In our study nearly half of the patients were only primary school education, and more than 1/5 of the patients were illiterate. These proportions were much greater than that reported in the literatures [3, 17, 28, 29]. While the junior high school patients have received a complete 9-year compulsory education, it is meaningful to be set as a group alone. In this study, the patients were divided into four groups: illiterate, elementary school, junior high school and high school above level, which was in line with the educational status in western China in the 1960s and was a more reasonable classification. And there were much more female patients totally, accounting for 81.9%, which were similar to literature reports, these patients were generally over 65 years and lived in countryside.
Education level could also affect the rehabilitation via patient's psychology
Postoperative pain is the most common symptom complained by patients . The preoperative patient's psychology is an important factor affecting the pain of patients after total knee arthroplasty [18, 30]. It is still a difficulty that how to identify better whether patients are at high risk of complications owing to psychiatric disorders . Kong et al.  clarified that education level was an independent risk factor for acute postoperative pain in total knee arthroplasty patients (0R = 1.23). The study by Pua et al.  found that education level would affect postoperative pain, and pain relief was significantly better in patients with higher education level, but there was no statistically significant difference. Preoperative and postoperative early intervention of depression psychology could play an important role in improving postoperative pain, whether education level was associated with negative psychological disorders was not further elaborated . In this study, we found that patients with education level above junior high school had significantly more pain relief and less anxiety than patients at primary school and illiterate groups. The degree of pain relief in the junior high school group and that in the senior high school above group was very similar, there was no difference between them, both were better than that in previous two groups, and the difference between them was significantly higher 3 months after surgery. In this study, there were 3 female patients of unexplained postoperative intractable pain, without evidence of infection, prosthesis loosening, prosthesis malposition, etc. Except for the junior high school group, there was 1 of the 3 female patients in each of the other three groups. This intractable pain did not seem to be related to the education level, but illiterate patients showed more severe depressive symptoms and repeatedly worried about future life and other matters. This study believes that education level is one of the influencing factors. However, more research is needed to determine whether postoperative pain can be predicted from education level .
Limitations of the study
There are also limitations in this study. The psychological anticipation and psychological status of patients in the studies were not analyzed in depth before surgery, including whether the accuracy and precision in their describing the degree of pain were consistent.