Family Function and Kinesiophobia in Patients after Hip Replacement Surgery: A Cross-Sectional Study on the Mediating Role of Illness Perception

Summary

Family-provided social support may reduce postoperative kinesiophobia through illness perception in patients after hip replacement surgery. These findings support the development of family-centered rehabilitation strategies to improve postoperative recovery and functional outcomes.

Abstract

This study investigated the association between family function and kinesiophobia in patients after hip replacement surgery and examined whether illness perception mediated this relationship. A total of 200 postoperative patients were included. On postoperative day 3, family function, illness perception, and kinesiophobia were assessed using the Family APGAR Index, Brief Illness Perception Questionnaire (BIPQ), and Tampa Scale of Kinesiophobia (TSK-17), respectively. Descriptive, univariate, and correlation analyses were conducted using SPSS software. Mediation analysis was performed using Model 4 of Hayes’ PROCESS 3.5 macro. Among the 200 participants, 59% experienced kinesiophobia. Family function was negatively correlated with kinesiophobia, whereas illness perception was positively correlated with kinesiophobia (r = -0.678 and 0.690, respectively; p < 0.001). Higher levels of family support were associated with lower levels of movement-related fear. Illness perception partially mediated the relationship between family function and kinesiophobia (β = -0.208, p < 0.05). The prevalence of postoperative kinesiophobia among patients after hip replacement surgery was high. The findings suggest that better family functioning may be associated with lower kinesiophobia, mediated by more positive illness perceptions. These results indicate that family support and cognitive appraisal should be considered when developing postoperative rehabilitation interventions.

Introduction

Hip replacement surgery (HRS) is commonly used to treat end-stage hip joint diseases. The procedure replaces the damaged joint with a prosthetic implant to relieve pain, correct deformity, and restore hip function. With advances in surgical techniques and perioperative management, HRS has become one of the most effective orthopedic procedures¹. Nearly 100,000 hip replacement procedures were performed in Italy in 2018², and the number of procedures is projected to continue increasing in both the United States and the United Kingdom^3,4. However, successful postoperative recovery depends not only on surgical outcomes but also on effective rehabilitation and early mobilization⁵. Enhanced Recovery After Surgery (ERAS) protocols emphasize early postoperative activity to promote functional recovery, yet many patients avoid rehabilitation exercises because of fear related to movement and pain⁶. Kinesiophobia refers to an excessive and irrational fear of physical movement caused by concerns about pain, injury, or reinjury^7,8. Previous studies have reported that the prevalence of postoperative kinesiophobia after HRS ranges from 40% to 60%⁹. Persistent kinesiophobia may negatively affect rehabilitation by increasing pain sensitivity, impairing proprioception, and delaying functional recovery^10,11,12,13. Physiological factors, including postoperative pain and limited joint mobility, as well as psychosocial factors such as low self-efficacy, insufficient social support, and catastrophic thinking, have all been associated with the development of kinesiophobia¹⁴.

The biopsychosocial model highlights the important influence of psychological and social factors on postoperative recovery¹³. Family support is particularly important for patients recovering from HRS because rehabilitation mainly occurs in the home environment after discharge. Family function reflects the ability of family members to provide emotional support, maintain communication, fulfill roles, and solve problems collaboratively¹⁵. Previous studies have shown that better family function is associated with improved health behaviors and reduced kinesiophobia^16,17. Illness perception refers to patients’ cognitive and emotional understanding of disease and treatment experiences^18,19. According to Leventhal’s Common-Sense Model of Self-Regulation (CSM), individuals develop cognitive and emotional representations of illness that influence coping behaviors and health outcomes. Within this framework, social support may shape illness perception and subsequently influence behavioral responses such as kinesiophobia. Previous studies have demonstrated that family function is associated with illness perception and that more positive illness perception is associated with lower levels of kinesiophobia^20,21.

However, the potential mediating role of illness perception in the relationship between family function and kinesiophobia among patients after HRS remains unclear. This study investigated the association between family function and kinesiophobia in patients after HRS and examined whether illness perception mediates this relationship. It was hypothesized that family function would be negatively associated with illness perception and kinesiophobia, that illness perception would be positively associated with kinesiophobia, and that illness perception would mediate the relationship between family function and kinesiophobia.

Protocol

This study was approved by the Institutional Review Board of Guizhou Medical University (Approval No.: 2024 Ethical Review No. 157). All participants received a detailed explanation of the study procedures before enrollment and provided written informed consent. All procedures were conducted in accordance with the Declaration of Helsinki and relevant institutional ethical guidelines.

1. Study design

A cross-sectional study design was adopted, and convenience sampling was conducted at three tertiary general hospitals in Guizhou Province between November 2024 and June 2025. These hospitals were selected because of their high volume of hip replacement procedures and implementation of standardized rehabilitation protocols. The overall study workflow, including patient recruitment, data collection, and statistical analysis, is presented in Figure 1.

[Place Figure 1 here]

1. Sample size calculation
   Sample size estimation was based on the principle that the required sample size for multivariate analysis should be five to ten times the number of study variables²². A total of 22 variables were included in the study, consisting of 14 demographic and clinical variables, 5 dimensions of the Family APGAR Index, 2 dimensions of the Brief Illness Perception Questionnaire (BIPQ), and 1 dimension of the Tampa Scale of Kinesiophobia. Accordingly, the estimated sample size ranged from 110 to 220 participants. After accounting for a potential 20% invalid questionnaire rate, the required sample size increased to 138–276 participants.
2. Participants
   The inclusion criteria were as follows: age ≥18 years; completion of hip replacement surgery for hip joint dysfunction caused by different etiologies; ability to communicate effectively and complete the questionnaire independently or with assistance; and provision of written informed consent. The exclusion criteria included severe cardiac, hepatic, or renal dysfunction; malignant tumors; severe trauma involving multiple organs; simultaneous hip and knee replacement; and severe postoperative complications, including deep vein thrombosis, dislocation, or infection.

2. Tools

1. Family APGAR Index, APGAR
   Family function was assessed using the Family APGAR Index²³. The scale consists of five items evaluating adaptability, partnership, growth, affection, and resolve. Each item is scored on a 3-point Likert scale ranging from 0 (“hardly ever”) to 2 (“always”), resulting in a total score ranging individually from 0 to 10. Higher scores indicate better family function. The Chinese version of the scale was introduced in 1995²⁴. The Cronbach’s alpha coefficient in this study was 0.746.
2. Brief Illness Perception Questionnaire (BIPQ)
   Illness perception was evaluated using the Brief Illness Perception Questionnaire (BIPQ)²⁵. The questionnaire contains nine items, with the ninth item assessing perceived disease causes through an open-ended question and therefore excluded from quantitative scoring. Consistent with the original BIPQ recommendations, the cognitive and emotional dimensions were interpreted collectively to characterize illness perception, rather than using the instrument as a unidimensional summed scale. The Chinese version of the scale was introduced by Sun et al.²⁶. The Cronbach’s alpha coefficient in this study was 0.738.
3. Tampa Scale of Kinesiophobia (TSK-17)
   Kinesiophobia was assessed using the 17-item Tampa Scale of Kinesiophobia (TSK-17)²⁷. The scale was originally developed by Kori et al.²⁸ to evaluate fear of movement associated with pain. Each item is scored on a 4-point Likert scale ranging from “strongly disagree” to “strongly agree.” Items 4, 8, 12, and 16 are reverse-scored. Total scores range from 17 to 68, with scores >37 indicating the presence of kinesiophobia²⁹. Higher scores indicate greater fear of movement. The Cronbach’s alpha coefficient in this study was 0.944.

3. Control variables

Demographic variables included sex, age, Body Mass Index (BMI), place of residence, marital status, educational level, employment status, and monthly household income. Clinical variables included preoperative diagnosis, presence of chronic diseases, type of replacement surgery, preoperative Numerical Rating Scale (NRS) score, duration of preoperative pain, and postoperative NRS score.

4. Data collection

Participants were recruited consecutively until the required sample size was reached. Written informed consent was obtained before data collection. To ensure consistency, the three postgraduate students responsible for data collection completed a one-week standardized training program covering questionnaire administration and psychological assessment procedures.

Questionnaires were administered on postoperative day 3. Most questionnaires were self-administered. For participants with visual impairment or severe fatigue, trained investigators conducted interviewer-assisted assessments by reading the questionnaire items verbatim. Before questionnaire administration, a standardized introductory statement was used to explain the study's purpose, confidentiality measures, and the voluntary nature of participation. When clarification was required, investigators used a pre-approved glossary of neutral explanations to minimize reporting bias.

A total of 206 questionnaires were distributed. Six questionnaires were excluded because of incomplete responses or participant withdrawal, resulting in 200 valid questionnaires and an effective response rate of 97%.

Postoperative day 3 was selected as the assessment time point because patients are generally transitioning from acute postoperative recovery to independent or semi-assisted mobilization during this period. Compared with the first 48 hours after surgery, the influence of acute postoperative pain and residual anesthetic effects is reduced, allowing a more stable assessment of kinesiophobia and illness perception.

5. Data analysis

Statistical analyses were performed using IBM SPSS Statistics version 27.0 (Armonk, NY, USA; RRID: SCR_002865). Patients with TSK-17 scores >37 were classified into the kinesiophobia group. Chi-square tests were used to compare differences in kinesiophobia prevalence across demographic and clinical characteristics. Pearson correlation analysis was conducted to evaluate the relationships among family function, illness perception, and kinesiophobia.

Harman’s single-factor test was performed to assess common method bias, with the criterion that the variance explained by the first factor should be <50%²⁹. Before mediation analysis, exploratory moderation analysis was conducted using PROCESS Model 1 to determine whether illness perception functioned as a moderator. Because the interaction terms were not statistically significant, a subsequent mediation analysis was conducted using PROCESS version 3.5 (RRID: SCR_021369) with Model 4.

Normality and multicollinearity assumptions were evaluated using Q-Q plots and Variance Inflation Factors (VIFs), respectively. Variables that showed significant associations in univariate analyses were included as covariates in the mediation model. Indirect effects were evaluated using the bootstrap method with 5,000 resamples.

Results

1. Descriptive findings: Scores on family function, illness perception, and kinesiophobia

Among the 200 HRS patients, the mean kinesiophobia score was 43.15 ± 9.64. This indicates a high prevalence rate of 59%. The family function score and illness perception score averaged 6.27 ± 2.34 points. Illness perception was represented by the weighted index of its cognitive and emotional components, which yielded an average score of 40.32 ± 9.59.

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Discussion

During the postoperative rehabilitation period, patients undergoing hip replacement surgery often experience reduced self-care ability and increased dependence on family caregivers. Therefore, this study examined the relationships among family function, illness perception, and postoperative kinesiophobia.

The findings demonstrated that better family function was associated with lower levels of illness perception and kinesiophobia. Family members represent an important source of emotional and i...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Broadbent et al. [25]	Standard scale	Measurement of illness perception
Smilkstein G. [23]	Standard scale	Assessment of family function
IBM Corp. (Armonk, NY, USA)	Version 27.0; RRID: SCR_002865	Descriptive and inferential statistics
Research Team (Pilot-tested)	N/A	Collection of demographic and clinical data
Microsoft Corp. (Redmond, WA, USA)	Microsoft 365	Data entry and management
Andrew F. Hayes	Version 3.5; RRID: SCR_021369	Mediation analysis
Kori et al. [28]	Standard scale	Evaluation of kinesiophobia