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

Abstract

Purpose

Patient-reported outcome measures (PROMs) are being used more frequently in total knee arthroplasty (TKA). By utilizing high-quality scales, surgeons can achieve a more comprehensive and accurate evaluation of the effectiveness of TKA surgery. Currently, there is no widely accepted conceptual model for TKA PROMs. The objective of this study is to fill this gap by developing a conceptual model and preliminary content for a PROM that is specifically designed for TKA patients in mainland China.

Methods

The study design consisted of three stages: (1) a targeted literature review followed by the formation of a conceptual model pool; (2) qualitative data collection involving experts and patients, leading to the development of the preliminary Chinese TKA PROM (CTP); and (3) review of the CTP by experts using the Delphi method, along with cognitive debriefing interviews with patients.

Results

64 patients and 28 experts took part in this study. The conceptual model focused on six key concepts: pain, symptom, function, quality of life, expectation, and satisfaction. To match the model, the authors developed a total of 35 items.

Conclusion

A conceptual model and preliminary content for CTP was developed with substantial participation from patients and a multidisciplinary group of experts. The integration of patient and clinical perspectives ensured a comprehensive representation of all relevant disease experiences and the focus of clinical practice. With further refinement through psychometric testing, the CTP is positioned to provide a standardized, comprehensive measure for research specific to Chinese TKA patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11136-024-03850-6.

Plain English summary

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.

Introduction

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).

Methods

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.

Fig. 1.

Flowchart of the study design

Stage 1: February 2022–January 2023

The study involved a comprehensive search on PubMed, Embase, Web of Science, Scopus, China National Knowledge Infrastructure (CNKI), Wanfang Data Knowledge Service Platform (Wan Fang), and VIP Chinese Journal Service Platform (VIP). To comprehensively identify psychometrically validated PROMs for TKA patients, we employed keywords from three terms: (1) patient-reported outcome measure; (2) measurement properties (including reliability, validity, internal consistency, responsiveness, measurement error, and minimal clinically important difference); and (3) TKA. The search strategy used for PubMed aligns with the research conducted by Wang et al. [10]. Eligible articles were those published as full texts in English or Chinese, specifically detailing the development or assessment of measurement properties of PROMs utilized in TKA. Exclusion criteria were applied to articles that: (1) lacked reporting on the measurement properties; (2) did not focus on TKA patients; (3) were not in full report format.

Following the elimination of duplicate articles, two reviewers (CX and LL) independently screened titles and abstracts, identifying eligible articles. Subsequently, full manuscripts were extracted and reviewed for final inclusion. Any discrepancies between the reviewers were resolved through discussion. The dimensions and items included in the PROMs that met the inclusion criteria were extracted and formed a conceptual model pool (CMP). In addition, we searched the China Health and Retirement Longitudinal Study (CHARLS) database for relevant items, which offers a comprehensive overview of the behaviors of older adults in China, including physical activity, dietary habits, social engagement, and health-related behaviors. The insights gained from this stage were instrumental in developing a semi-structured interview guide.

Stage 2: February–June 2023

This semi-structured interview guide was then applied in conducting 60-min, one-on-one interviews with TKA related experts. During these in-depth interviews, the experts reviewed the CMP, providing input on wording, organization, and content; discussed the impacts of living with TKA; and considered other elements of a PROM (eg, length of the questionnaire, ideal response options). The interviews were documented through audio recordings and transcribed verbatim. Two members of the study team (CX and SXY) conducted the interviews and subsequently coded and analyzed the transcripts. Additionally, a semi-structured interview guide was developed for subsequent use in focus group sessions and individual interviews with TKA patients.

TKA patients were recruited through purposive sampling. On May 8th, 2022, an in-person patient focus group lasting 90 min was held at Honghui Hospital. Subsequent individual interviews were conducted. During these sessions, participants discussed the PROM dimensions and item pool, providing insights into the impacts of their condition on daily life. The discussions were audio-recorded and transcribed verbatim. Two members of the study team (CX and JW) conducted coding and analysis of the transcripts, focusing on confirming and elaborating on the insights identified in interviews. Additionally, patient preferences regarding various elements of the PROM, such as the recall period and the ideal mode and setting for completing the questionnaire, were identified.

The insights gathered from these interviews were utilized to develop the preliminary CTP, along with item response options and instructions. All contents were drafted in simplified Chinese.

Stage 3: July–December 2023

This session included two rounds of the Delphi method, followed by one round of formal cognitive debriefing interviews. We followed the recommendations provided by the CREDES (Guidance on Conducting and Reporting Delphi Studies) [12].

TKA Experts from multiple fields were involved in Delphi consultation, including those in joint surgery, orthopedic nursing, rehabilitation medicine, medical statistics, orthopedic medical device development, and medical psychology. The experts had to meet the following criteria: (1) extensive practical or research experience in the fields related to TKA, with a minimum of 15 years of working experience; (2) bachelor’s degree or above; (3) intermediate technical title or above; (4) motivation for this study; and (5) following the principle of informed consent.

The principal investigators (CX, JBM and LS) contacted experts by email or WeChat, distributing expert consultation questionnaires (Table 1) and reminding the expert to return them within 2 weeks. The researcher contacted experts who did not respond within 2 weeks to inquire about the progress. After the questionnaires from the first round were returned, the researchers (CX and JBM) analyzed the experts’ opinions and organized the research team discussion. Items were removed according to the criteria of mean score of the importance < 3.5 and coefficient of variation (CV) > 0.25 [13], and items were added or modified according to the experts’ feedback. Based on the results of the first round of consultation, a second round of consultation questionnaires was designed. The results of the first round were provided in the second round of questionnaires so that the experts could understand how these modifications were created. The same steps were followed to distribute and collect the questionnaires. The consultation was concluded when the experts reached a consensus. Therefore, two rounds of expert consultation were conducted with a one-month interval between them.

Table 1.

Content of expert consultation questionnaire

Sections	Content
Section 1: Survey Introduction	(1) Study overview: background, purpose, and significance of the study; (2) Development process: the process of constructing the first draft of the dimensions and items; (3) Expert consultation: the purpose of expert consultation, questionnaire components, expected return time, and contact information of the researchers
Section 2: Experts’ Information and Self-evaluation	(1) Basic information of experts: including age, gender, department, years of work, highest education; technical title, and main research fields; (2) Consensus (Cs): Self-evaluation of the expert’s familiarity with the consultation content. Scores were assigned as follows: very familiar (1.0), more familiar (0.8), generally familiar (0.5), less familiar (0.3), and unfamiliar (0.1); (3) Criterion of Appropriateness (Ca): Self-evaluation by experts of the basis for their judgment in expressing their opinions. Scores were assigned as follows: practical experience (0.5, 0.4, 0.3), theoretical analysis (0.3, 0.2, 0.1), references (0.1, 0.1, 0.1), and intuition (0.1, 0.1, 0.1)
Section 3: Expert assessment and recommendations for dimensions and items	(1) First draft of the dimensions and items; (2) Reasonability of the dimensions and items was evaluated by experts using a 5-point Likert scale: Very important (5 points), Important (4 points), Fair (3 points), Not Very important (2 points), Unimportant (1 point); (3) Modification Comments: comments from experts on any dimensions and items are invited, including adding, removing, or modifying

Then, one round of formal cognitive debriefing interviews was conducted with TKA patients recruited from Honghui Hospital. Two members of the study team (CX and XFC) conducted face-to-face interviews with each patient. The interviews followed a semi-structured interview guide specifically designed to assess the relevance, comprehensibility, and comprehensiveness of the CTP. Participants utilized the CTP through the think-aloud method, a standardized approach to cognitive debriefing that minimizes interviewer bias and offers valuable insights into participant comprehension [14]. The interviews were audio-recorded and transcribed verbatim. Two members of the study team (CX and JW) coded the transcripts and identified any sections of the CTP that required revisions [15].

Statistical analysis

All statistical analyses were conducted using SPSS 24.0 (Chicago, IL). The significance level was set at 0.05. The normality of the data distribution was assessed using the Kolmogorov–Smirnov test, and it was found that all the data followed a normal distribution. The expert profile was presented using mean, standard deviation, or frequency and percentage. In stage 3, the degree of expert authority was determined through the expert authority coefficient (Cr), computed as the arithmetic mean of Cs and Ca. The degree of expert opinion concentration was evaluated using the mean importance score and CV. Additionally, the degree of coordination among expert opinions was quantified by Kendall's W coefficient.

Results

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

Table 2.

Basic information of experts in each stage

Participant classification	Concept elicitation Interviews (N = 12)	Delphi– Round 1 (N = 28)	Delphi – Round 2 (N = 24)
Age (Mean ± SD, years)	48.2 ± 3.2	43.1 ± 6.3	42.9 ± 6.4
Sex, n (%)
Male	9 (75.0%)	21 (75.0%)	18 (75.0%)
Female	3 (25.0%)	7 (25.0%)	6 (25.0%)
Working experience (Mean ± SD, years)	24.6 ± 3.5	18.7 ± 6.6	18.8 ± 6.8
Research area, n (%)
Joint surgery	8 (66.7%)	17 (60.7%)	16 (66.7%)
Orthopedic nursing	2 (16.7%)	4 (14.3%)	4 (16.7%)
Rehabilitation medicine	1 (8.3%)	3 (10.7%)	3 (12.5%)
Medical statistics	0 (0.0%)	2 (7.1%)	0 (0.0%)
Medical device development	0 (0.0%)	1 (3.6%)	0 (0.0%)
Medical psychology	1 (8.3%)	1 (3.6%)	1 (4.2%)

Table 3.

Basic information of patients in each stage

	Concept Elicitation		Cognitive Debriefing
	Patient Focus Group (N = 12)	Individual Interviews (N = 32)	Patient interviews (N = 20)
Age (Mean ± SD, years)	65.0 ± 6.0	65.1 ± 6.5	67.8 ± 4.8
Sex, n (%)
Male	3 (25.0%)	8 (25.0%)	6 (30%)
Female	9 (75.0%)	24 (75.0%)	14 (70%)
Postoperative time (M)	18.5 ± 6.7	17.8 ± 4.3	16.9 ± 4.7
Employment status
In work	3 (25%)	9 (28.1%)	4 (20%)
Be unemployed	1 (8.3%)	2 (6.3%)	2 (10%)
Retired	8 (66.7%)	21 (65.6%)	14 (70%)
Living situation
Living alone	1 (8.3%)	4 (12.5%)	2 (10%)
With spouse	7 (58.3%)	20 (62.5%)	13 (65%)
With children	4 (33.3%)	8 (25%)	5 (25%)
Education
Primary school or below	2 (16.7%)	5 (15.6%)	3 (15%)
Middle school	5 (41.7%)	12 (37.5%)	6 (30%)
High school or above	4 (33.3%)	12 (37.5%)	9 (45%)
University	1 (8.3%)	3 (9.4%)	2 (10%)

M: Months

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).

Fig. 2.

Flowchart of the article selection process

Fig. 3.

A conceptual model pool (CMP) for Chinese TKA PROM

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).

Table 4.

The degree of centralization and coordination of the importance scores of items in two rounds of Delphi expert consultation

Items	First Round		Second Round		Whether to ultimately include it in the CTP and its corresponding dimension
	Importance score	CV	Importance score	CV
Overall pain level	4.82 ± 0.48	0.100	4.96 ± 0.20	0.040	Yes (Pain)
Location	4.68 ± 0.72	0.154	4.79 ± 0.59	0.123	Yes (Pain)
Frequency	4.00 ± 0.77	0.193	4.33 ± 0.76	0.176	Yes (Pain)
Swelling	3.96 ± 0.88	0.222	4.29 ± 0.75	0.175	Yes (Symptoms)
Stiffness	4.46 ± 0.69	0.155	4.71 ± 0.46	0.098	Yes (Symptoms)
Weakness	4.14 ± 0.89	0.215	4.29 ± 0.75	0.175	Yes (Symptoms)
Hearing any sounds from the knee a	2.61 ± 1.20	0.460	–		No
Taking off socks or shoes while sitting	4.00 ± 0.72	0.180	4.54 ± 0.66	0.145	Yes (Function)
Walking on a flat surface	4.50 ± 0.69	0.153	4.88 ± 0.34	0.070	Yes (Function)
Climbing up or down stairs	4.75 ± 0.52	0.109	4.92 ± 0.28	0.057	Yes (Function)
Squatting	4.18 ± 0.77	0.184	4.38 ± 0.71	0.162	Yes (Function))
Jogging	3.82 ± 0.67	0.175	4.08 ± 0.72	0.176	Yes (Function)
Sitting for a long time a	2.61 ± 0.92	0.352	–		No
Light Household activity (sweep, vacuum, cleaning)	4.25 ± 0.93	0.219	4.50 ± 0.72	0.160	Yes (Function)
Riding a bicycle a	3.07 ± 1.12	0.365	–		No
Bath/Shower	4.46 ± 0.74	0.166	4.71 ± 0.46	0.098	Yes (Function)
Standing up from a low sitting position without using the armrests	4.18 ± 0.82	0.196	4.46 ± 0.72	0.161	Yes (Function)
Get in/out of a car	4.21 ± 0.92	0.219	4.46 ± 0.59	0.132	Yes (Function)
Using public transportation a	3.64 ± 1.31	0.360	–	–	No
Mild field labor	3.75 ± 0.89	0.237	4.17 ± 0.76	0.182	Yes (Function)
Standing for a long time a	4.21 ± 1.13	0.268	–	–	No
Hill walking a	3.54 ± 1.04	0.294	–	–	No
Walking up and down an incline a	3.68 ± 0.94	0.255	–	–	No
Cross-legged sitting a	3.57 ± 1.10	0.308	–	–	No
Kneeling a	3.32 ± 0.90	0.271	–	–	No
Bending to floor	3.54 ± 0.84	0.237	3.79 ± 0.66	0.174	Yes (Function)
Going shopping a	3.46 ± 0.96	0.277	–	–	No
Rising from bed a	3.61 ± 1.03	0.285	–	–	No
Squatting to use the toilet a	3.14 ± 1.15	0.366	–	–	No
Getting on/off toilet	3.75 ± 0.70	0.187	4.00 ± 0.59	0.148	Yes (Function)
stepping to the sidea	3.54 ± 1.29	0.364	–	–	No
Turning or twisting on the kneea	3.79 ± 1.17	0.309	–	–	No
One-leg standinga	3.54 ± 1.14	0.322	–	–	No
Lower limb muscle strength traininga	3.14 ± 0.93	0.296	–	–	No
Stretchinga	2.39 ± 0.96	0.402	–	–	No
Outdoor fitness activities (Tai Chi or Square dancing)	4.36 ± 0.87	0.200	4.67 ± 0.56	0.120	Yes (Function)
Taking care of childrena	2.32 ± 1.02	0.440	–	–	No
Overall quality of life	4.11 ± 0.88	0.214	4.54 ± 0.51	0.112	Yes(Quality of life)
Sleep qualitya	2.71 ± 1.08	0.399	–	–	No
Reduce strenuous activity to avoid potential injurya	2.21 ± 0.92	0.416	–	–	No
Lack of confidence of the kneea	2.96 ± 0.84	0.284	–	–	No
Visiting friends and relatives	3.86 ± 0.71	0.184	4.25 ± 0.74	0.174	Yes(Quality of life)
Embarrassed when people see me	3.61 ± 0.69	0.191	3.96 ± 0.81	0.205	Yes(Quality of life)
Feel being a burden to close relatives a	2.46 ± 0.69	0.280	–	–	No
Anxiety or Depression	4.21 ± 0.69	0.163	4.25 ± 0.74	0.174	Yes(Quality of life)
Looking forward to relieving pain	4.82 ± 0.39	0.081	4.96 ± 0.20	0.040	Yes(Expectation)
Looking forward to carry out activities of daily living	4.61 ± 0.69	0.150	4.58 ± 0.72	0.157	Yes(Expectation)
Looking forward to perform leisure, recreational, or sport activities	4.43 ± 0.79	0.178	4.67 ± 0.64	0.137	Yes(Expectation)
Satisfied with pain relief	4.57 ± 0.74	0.162	4.71 ± 0.55	0.117	Yes(Satisfaction)
Satisfied with the ability to resume daily activities	4.32 ± 0.86	0.199	4.50 ± 0.72	0.160	Yes(Satisfaction)
Satisfied with the ability to resume leisure, recreational, or sport activities	4.25 ± 0.75	0.176	4.58 ± 0.65	0.142	Yes(Satisfaction)

The data is presented in the form of mean ± standard deviation. CV: Coefficient of variation. ^aItems deleted in the first round of Delphi correspondence

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.

Table 5.

Self-evaluation by experts of the basis for their judgment

Judgement basis	First round (n = 28)				Second round (n = 24)
	High	Medium	Low		High	Medium	Low
Practical experience	15	11	2		15	9	0
theoretical analysis	15	13	0		14	10	0
references	12	11	5		12	9	3
intuition	3	7	18		3	6	15
Ca value	0.90 ± 0.07				0.92 ± 0.06

The data is presented in the form of mean ± standard deviation. Ca: Criterion of appropriateness

Table 6.

Self-evaluation of the expert’s familiarity with the consultation content

Familiarity	First Round (n = 28)	Second round (n = 24)
Very familiar	16	18
More familiar	12	6
Generally familiar	0	0
Less familiar	0	0
Unfamiliar	0	0
Cs Value	0.91 ± 0.10	0.95 ± 0.09

The data is presented in the form of mean ± standard deviation. Cs: Consensus

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.

Discussion

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.

Conclusion

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.

Supplementary Information

Below is the link to the electronic supplementary material.

Author contributions

Lei Shang and Jianbing Ma contributed to the study conception and design. Material preparation, data collection and analysis were performed by Chao Xu, Jie Wei, Liang Li, Shuxin Yao and Xiaofeng Chang. The first draft of the manuscript was written by Chao Xu and Jie Wei and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Funding

This study was supported by the National Natural Science Foundation of China (Grant no. 82173627), Key Research and Development Program of Shaanxi Province (No. 2023-YBSF-464) and Cultivation Project for General Project of Xi’an Health Commission (No. 2024ms10).

Data availability

The data that support the findings of this study are available from the corresponding authors [LS or JBM] upon reasonable request.

Declarations

Conflict of interests

The authors have no relevant financial or non-financial interests to disclose.

Ethical approval

This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the medical ethics committee of Honghui Hospital (Date: 02.25.2022; No:202202021).