PURPOSE OF THE STUDY The aim of the study was, first, to assess satisfaction of our patients after primary total knee arthroplasty (TKA) at various intervals of follow-up. Second, a list of pre- and peri-operative factors with potential effects on patient satisfaction was analysed. The third objective was to identify conditions under which a result of replacement could be considered definite with a little probability of further unexpected development. A more detailed knowledge of unsatisfied patients may provide valuable information for use in pre-operative evaluation, indication for surgery, as well as in the surgery itself. MATERIAL AND METHODS This prospective study consisted of 826 patients who underwent primary TKA between September 2010 and March 2015 and had at least one complete post-operative examination. Our group included 296 men and 530 women. The average age at primary TKA was 68.9 (45-87). Primary osteoarthritis was the most frequent indication to surgery (82.6 %). The followup period ranged from 1 month to 3 years. On each follow-up examination, every patient received an original questionnaire with 24 questions concerning the course of their post-operative period (between the discharge from hospital and the planned follow-up). The patients assessed the degree of satisfaction with surgery outcomes on a scale ranging from "fully satisfied" to "dissatisfied" and expressed their overall satisfaction in percents. RESULTS At the final follow-up, 6.5% of the patients were not satisfied with the outcome. The patients' overall satisfaction was 90.2 % (i.e., responses to the question of how you were satisfied with surgery). Significantly more satisfied patients were among those with primary osteoarthritis. Their satisfaction was related to the level of the UCLA activity rating, feelings of uncertainty when walking and to the functional ability component of the KSS system. On the other hand, more dissatisfied patients were found among those with several previous operations, a higher ASA score or a higher number of risk factors (Charlson comorbidity score etc.). The duration of pre-operative complaints had no relation to post-operative satisfaction. Similarly, there was no relation between VAS-evaluated pain intensity before TKA and patient satisfaction after arthroplasty. Obesity and satisfaction were not inter-related either. DISCUSSION Assessment of satisfaction is one of the Patient Reported Outcome Measures (PROMs) used by patients to evaluate the effect of a therapeutic method. These instruments aid in assessing the degree to which the method has met the needs and expectations of patients. It is relevant to emphasise that subjective factors, such as expectation or satisfaction, do not depend on the therapeutic procedure only. Recent reports have shown that, in 10% to 30% of the patients, the TKA outcome has not met their expectations. More detailed studies draw attention to the fact that there are more dissatisfied patients after TKA than those after THA. When satisfaction with pain relief is considered, the number of dissatisfied patients is even lower (72%-86%). CONCLUSIONS An analysis of the patients' responses shows that the rate of satisfaction is high shortly after surgery but declines gradually thereafter. The overall satisfaction is stable about 12 months after the surgery. The number of dissatisfied patients or those reporting pain after TKA in our study is in agreement with the results reported in relevant literature. The associations found here will be used in preparing a tool for clinical outcome prediction.
Key words: total knee arthroplasty, outcome evaluation, patient-reported outcome measures, satisfaction, dissatisfaction, pain after total knee arthroplasty, function after total knee arthroplasty.