Abstract
Patellofemoral pain (PFP) is a multifactorial condition closely associated with deficits in knee and hip muscle strength, aberrant movement patterns, and psychological factors. These factors not only contribute to the onset and recurrence of pain but also influence patients’ responsiveness to rehabilitation interventions. This study aimed to evaluate how patients with PFP characterized by different baseline profiles respond to a combined intervention of patient education and exercise (EDU + EX) compared with exercise alone (EX). The findings are expected to provide empirical evidence supporting the precision and personalization of PFP rehabilitation strategies, while reducing unnecessary intervention costs associated with the indiscriminate implementation of patient education programs. Participants were randomly assigned to either the EDU + EX group or the EX group for an 8-week rehabilitation intervention, followed by a 20-week post-intervention assessment. The primary outcome measure was patellofemoral joint load. Potential effect modifiers included body mass index, Anterior Knee Pain Scale score, pain catastrophizing, fear of movement, hip–knee kinematic parameters, and hip and knee muscle strength. A linear mixed-effects model was employed to examine how these patient-specific characteristics influenced responsiveness to the EDU + EX and EX interventions. Compared with baseline, patellofemoral joint load was significantly reduced after 8 weeks of intervention in both the EDU + EX group (3.46, P = 0.0013) and the EX group (3.38, P < 0.001). Patients with PFP exhibiting gluteus minimus strength < 8.37 N/kg (2.93, 95% CI: − 6.28 to 0.42), gluteus medius strength < 16.82 N/kg (–3.46, 95% CI: − 7.14 to 0.50), vastus lateralis strength < 44.87 N/kg (1.86, 95% CI: − 5.03 to 1.31), or a Tampa Scale for Kinesiophobia score > 37 (–11.45, 95% CI: − 15.47 to − 2.13) were more likely to benefit from the EDU + EX intervention. In contrast, PFP patients with gluteus minimus strength > 8.37 N/kg (3.29, 95% CI: − 0.58 to 7.15) or vastus lateralis strength > 44.87 N/kg (4.15, 95% CI: 1.37 to 6.93) demonstrated greater improvement following the EX intervention. For PFP patients with hip muscle weakness, knee muscle imbalance, or elevated fear of movement, the EDU + EX intervention demonstrates superior comprehensive benefits by improving postural control and cognitive–behavioral adaptation, thereby enhancing rehabilitation outcomes. In contrast, for patients with sufficient hip and knee strength and stable psychological profiles, the EX intervention alone appears adequate to meet rehabilitation demands. This stratified intervention strategy may enhance the efficiency of resource utilization while maintaining therapeutic effectiveness.
Data availability
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.
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The authors would like to express gratitude to the participants for their voluntary participation in this study.
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ZZ contributed to the conceptualization, methodology, investigation, data curation, formal analysis, and software development. He also played a significant role in the writing of the original draft and reviewing and editing the manuscript. TF contributed to the investigation, data curation, formal analysis, and visualization. Additionally, she provided substantial input to the writing and editing of the manuscript. JW contributed to the conceptualization, methodology, and project administration. He also provided valuable contributions to data curation, formal analysis, and the review and editing of the manuscript. YS, as the corresponding author, made significant contributions to the conceptualization, methodology, project administration, supervision, and validation. He was also involved in securing funding, providing resources, and overseeing the writing and editing of the manuscript. YS critically revised the manuscript for important intellectual content and provided overall guidance throughout the project.
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The study was conducted in accordance with the ethical standards of the Declaration of Helsinki, with ethics approval obtained from the Ethics Committee of the authors’ affiliated institution (approval number: 2024-22). The study was prospectively registered with the Chinese Clinical Trial Registry (Registration No. ChiCTR2500103109) on 25-05-25.
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Zhang, Z., Fan, T., Wu, J. et al. Patient characteristics modify the effects of education plus exercise on patellofemoral joint loading: a secondary effect-modifier analysis of a randomized controlled trial. Sci Rep (2026). https://doi.org/10.1038/s41598-026-48631-y
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DOI: https://doi.org/10.1038/s41598-026-48631-y
