A multi-phase approach for developing a conceptual model and preliminary content for patient-reported outcome measurement in TKA patients: from a Chinese perspective

Currently, there is no patient-reported outcome scale specifically developed for Chinese patients who have undergone total knee arthroplasty. This study aims to address this gap by exploring the key aspects and preliminary content that should be included in a Chinese total knee arthroplasty patient-reported outcome scale. Through multiple rounds of discussions with total knee arthroplasty patients and experts, a Chinese version of the total knee arthroplasty patient-reported outcome scale has been developed, which consists of 6 dimensions (pain, symptom, function, quality of life, expectation, and satisfaction) and 35 items. This scale will serve as the basis for future reliability and validity testing. Having a total knee arthroplasty patient-reported outcome scale tailored to the Chinese population will allow for a more accurate assessment of surgical effectiveness and provide better guidance for postoperative rehabilitation in China.

With a history spanning over 40 years, total knee arthroplasty (TKA) has emerged as a highly effective treatment for end-stage knee osteoarthritis (KOA) [1]. This procedure has consistently demonstrated its ability to improve the quality of life by alleviating pain and enhancing long-term knee function [2, 3]. Additionally, as TKA is an elective procedure, it is important to use patient-reported outcome measures (PROMs) to evaluate its effectiveness, going beyond traditional objective metrics [4].

PROMs offer unique advantages, such as: (1) reducing clinician biases and accurately representing the patient's health status from their perspective [5]; (2) fostering a more thorough understanding of patients' perspectives, aiding in the identification of potentially modifiable factors [6]; (3) facilitating patient follow-up, regardless of direct attendance [7]; and (4) assisting in the decision-making process for treatment interventions [8].

Currently, China has not yet developed its own PROM for TKA patients. Western PROMs are used in China, but it is challenging to apply foreign scales to Chinese patients due to cultural variations, customs, differences in disease diagnosis and treatment concepts, and socio-economic development levels between China and the West [9]. Additionally, the absence of a widely accepted PROMs conceptual model for TKA patients leads to inconsistent structures among the PROMs used in clinical practice. This lack of comparability ultimately hinders the widespread promotion and application of existing PROMs [10].

The conceptual model defines the meaning and scope of the measurement dimensions of the scale. Building a strong conceptual model is necessary to create a valid and reliable measurement instrument [11]. This study aims to develop a conceptual model and preliminary content for PROM specifically designed for TKA patients in mainland China. This endeavor will serve as the groundwork for the development of the final version of Chinese TKA PROM (CTP).

This study was designed in three stages, encompassing a targeted literature review, concept elicitation with TKA patients and related experts, and evaluation of the PROM’s content validity (Fig. 1). The patients included in this study had all undergone TKA surgery at least one year prior. The study adheres to the principles of the Declaration of Helsinki, and ethics approval was obtained from the medical ethics committee of Honghui Hospital (No.202202021). All participants provided written informed consent.

A diverse group of participants contributed to the study. Detailed professional and demographic information is presented in Tables 2 and 3.

In total, 235 articles were ultimately selected from 8,491 references (Fig. 2). Consequently, the study team identified and analyzed 57 PROMs (in 56 studies) [11, 16‐70]. Based on data extracted from the literature review, the study team developed a list of 8 dimensions and 135 items of CMP (Fig. 3).

Twelve experts participated in concept elicitation interviews. They reviewed the CMP, made suggestions for dimension and item settings. They confirmed all 8 dimensions and suggested merging “Mental & Emotional”, “Role (social & work)”, and “Quality of life” into a single category called "Quality of life". They also removed 56 items not in line with the Chinese lifestyle, such as golfing, entering and exiting bathtubs, skiing, etc.

Twelve TKA patients participated in the concept elicitation focus group, confirming the revised list of dimensions and items. Following the group discussion, 29 items deemed not highly relevant were removed at this stage.

A total of 32 TKA patients participated in individual concept elicitation interviews. The patients suggested including items that reflect the characteristics of the Chinese lifestyle, such as “Tai Chi” and “Square dancing”. As a result, 4 new items were added, 3 items were removed and 8 existing items were revised during this stage.

A 5-level Likert scale was used for response options, and a one-month duration was selected to facilitate accurate recall. Following these revisions, a preliminary CTP with 51 items was developed (Table 4).

In the first round of Delphi method, 32 questionnaires were distributed and 28 were collected, resulting in a valid questionnaire collection rate of 87.5%. Out of the 28 experts, 21 (75.0%) provided 49 modification suggestions. Moving on to the second round, 28 questionnaires were distributed and 24 were collected, achieving a valid questionnaire collection rate of 85.7%. From this round, 9 experts (37.5%) contributed 20 modification suggestions. These figures reflected the experts’ interest in the study and the relatively high level of motivation.

The Ca values for the two rounds of Delphi were 0.90 ± 0.07 and 0.92 ± 0.06, while the Cs values were 0.91 ± 0.10 and 0.95 ± 0.09. The Cr values for the two rounds of Delphi were 0.91 ± 0.07 and 0.94 ± 0.06, respectively (Tables 5 and 6). Both these values were higher than 0.7, indicating that the consultation results were reliable.

In this study, importance scores obtained from two rounds of Delphi consultation ranged from 2.21 to 4.82, and 3.79 to 4.96, respectively. The CV for the importance scores was found to be 0.08 to 0.46 in the first round and 0.04 to 0.21 in the second round (Table 4). Additionally, Kendall's W values for the two rounds of Delphi consultation were calculated to be 0.404 and 0.215, respectively (P < 0.001 for both). These results indicate consistent agreement among the experts' opinions. The CV in the second round was significantly smaller than that in the first round, suggesting that the opinions of experts tended to be more consistent.

Based on participant feedback, no dimensions needed adjustment. 22 items were deleted based on the screen criteria. Additionally, 16 items in the questionnaire were modified to enhance readability and clarity. Subsequently, the research team met to discuss and propose scoring rules for each item after the Delphi consultation.

20 patients contributed to cognitive debriefing interviews. They clearly understood all dimensions and items and were able to answer them using the provided response options. Based on their feedback, 4 items were revised to improve wording. Cognitive debriefing further confirmed the instructions were clear and that the recall period was appropriate. The patients took an average of 6.9 ± 2.4 min to complete the questionnaire. The final CTP includes 6 dimensions and 35 items (Supplemental Digital Content 1, CTP and scoring instructions). The dimension of expectation will be included in the preoperative version, while satisfaction will be included in the postoperative version.

PROMs enhance patient-clinician interactions by fostering open dialogue, emotional expression, and a balanced distribution of power during medical visits. Orthopedic surgeons now recognize that a critical outcome measure for TKA lies in discernible changes in PROMs [10]. By adopting high-quality PROMs, we can improve the accuracy of efficacy evaluations, provide targeted guidance for patient rehabilitation, and facilitate the early detection and intervention of abnormal functional states in TKA patients.

It is important to customize the global standard to meet specific conditions within each country, with addressing cross-cultural differences being a fundamental aspect of this challenge [71]. The TKA patient-specific PROM developed with a Western cultural background may not be perfectly suitable for Chinese individuals [72]. The disparities between Eastern and Western cultures regarding diet, health beliefs, behavioral habits, and economic environments significantly influence patients' demands for TKA, as well as their expectations, evaluations of surgical efficacy, and rehabilitation strategies [73, 74]. Consequently, there is a growing need for localized PROMs. Currently, no PROM is specifically designed for Chinese patients undergoing TKA. Therefore, it is crucial to develop a CTP that considers the social and cultural background of China, incorporates psychological factors, and can be easily used in Chinese medical institutions. In this study, we conducted a series of in-depth interviews and used the Delphi method to develop a conceptual model and preliminary content for the CTP. We gathered perspectives from both clinicians and patients, which laid a strong foundation for the future development of the formal version of the CTP.

Currently, TKA surgery is experiencing the fastest growth among individuals under 60 years old in Western countries. Younger patients often have higher expectations for their sports-related functions, which is also evident in the new Knee Society Scoring System and other functional evaluation scales [75]. However, Noble et al. emphasized tailoring the functional evaluation items to the specific needs of each population [49]. In this regard, the functional evaluation dimension of the CTP scale is designed to fully reflect the unique characteristics of Chinese patients. In China, elderly patients typically engage in activities like square dancing, Tai Chi, and aerobics [76]. However, activities such as golf, yoga, road cycling, and other Western exercises are not commonly practiced in China. This disparity is also reflected in the functional dimension of the CTP. In addition, the selection of assessment items specifically related to surgery is crucial for ensuring that evaluations are relevant, accurate, and applicable to surgical populations. Utilizing appropriate items ensures that assessments meaningfully reflect the intended outcomes of the surgery. This targeted approach ultimately supports better rehabilitation strategies and improves patient-centered care in orthopedic settings [77].

Chinese patients tend to be older and have more severe conditions when undergoing TKA surgery compared to patients in Western countries [78]. In economically disadvantaged areas, TKA treatment is often chosen as a last resort when the condition becomes unbearable. Consequently, Chinese patients primarily focus on pain relief and restoring basic daily life activities and sports functions, rather than high-intensity sports [73]. After conducting multiple rounds of interviews and surveys, this study identified 13 functional items that are crucial for the daily lives of Chinese patients.

Most TKA patients in China are over 60 years old, and a significant proportion of them have not received higher education [79]. In this study, fewer than 10% of the patients had received a university education. Particularly in economically disadvantaged areas of the central and western regions, many patients struggle to understand the content of the PROM due to their low level of education [72]. Therefore, when developing the scale, we revised item language multiple times based on patients' and experts' feedback to ensure clarity. Additionally, the design of the scale emphasizes the need to simplify the items as much as possible. The time it takes to fill in the form directly impacts the quality and completion rate of the scale [80]. Hence, by reducing the time needed to complete the form, we can improve the accuracy of the gathered information, lessen the burden on patients, alleviate clinicians' workload, and promote the widespread use of the scale in China [80]. In this study, the average time it took TKA patients to complete the CTP scale was 6.9 min, which was significantly shorter than the previous scale [10]. This result indicates that the scale's dimensions and item settings are appropriate.

In CTP, the functional dimension has a maximum score of 52 points, the pain dimension has 36 points, the symptom dimension has 18 points, the QOL dimension has 16 points, and both expectation and satisfaction have 12 points each. The weight of each dimension on the scale shows that function and pain carry the most significance, emphasizing their essential role for TKA patients, which aligns with previous research [57]. The validity of this allocation will be confirmed in subsequent psychological tests.

This study emphasizes the importance of integrating patient input using recommended qualitative research methods [81]. The approach used, concept elicitation, involves conducting interviews with patients to gather detailed descriptions of symptoms, impacts, and other aspects of their condition. By incorporating extensive patient input, the study ensures that the patient's voice and experience are central to the development of the CTP. Through multiple rounds of feedback from patients, the language used in the scale items has been improved to be more friendly, easily understood, and accepted by Chinese patients.

In addition to incorporating the patient voice, the study team actively sought input from a diverse group of experts, deliberately ensuring the inclusion of opinions from various professions. During these discussions, psychologists noted that Chinese people have limited involvement in community activities. Consequently, they proposed eliminating social activity-related items from the QOL dimension. However, they also emphasized the considerable significance of family-based social activities in Chinese society, which comprise the majority of social interactions. Therefore, it would be more suitable to incorporate an item specifically for visiting relatives and friends, as this effectively represents the quality and necessity of social interaction in Chinese culture.

Given that the scale construction needs to be tested for reliability, validity, and norms, this study will proceed with large clinical sample and multi-center patient interviews. This will allow for debugging and improving the scale, as well as statistically screening the items to ensure their suitability for clinical practice in China.

The conceptual model and preliminary content for CTP were developed through a secondary analysis of published literature and a series of qualitative and Delphi interviews. The CTP describes the perioperative concerns of Chinese TKA patients and experts. This work is a significant step towards creating a CTP specifically tailored for Chinese TKA patients.