Effectiveness of early physical therapy for patients with patellofemoral pain: a multicentre randomized clinical trial

Abstract

Patellofemoral pain (PFP) is a persistent musculoskeletal disorder in which pain may last for up to 20 years after diagnosis. PFP is also challenging to treat, with up to 60% of patients reporting poor or incomplete recovery of their pain and/or restoration of their functional levels one to eight years after treatment. This may suggest that delivering interventions supported by level 1 evidence may be not sufficient to manage PFP when the timing in which they are delivered is not considered. Because pain in the early stages after PFP development may be mild to moderate, people with PFP seems to seek care only when their symptoms are already chronic, whereas greater symptom duration (i.e., >4 months) has been considered as one of the main prognostic factors for PFP. In this scenario, delivering early physical therapy for patients with PFP may be helpful to optimize patients' responses after treatment, and to prevent long term complications. Also, although education and exercise therapy are currently recommended to manage PFP, it is possible that a minimal and cost-effective intervention (i.e., only education) may be beneficial for patients with acute PFP. Still, the effectiveness of early physical therapy has not been tested in patients with PFP. Therefore, the aims of this project are to investigate: i) the effectiveness of a 12-week early physical therapy program for people with acute PFP (i.e., 4-12 weeks of pain) as compared to a 12-week delayed physical therapy program for patients with chronic PFP (pain lasting for >4 months) for clinical and psychological outcomes; ii) the effectiveness of two early physical therapy programs, one based on patient education and another based on the delivery of a multimodal program with education plus exercise therapy, for clinical and psychological outcomes of patients with acute PFP; and iii) mediators for the changes on pain and function depending on symptom duration and timing of physical therapy.Participants will be recruited in three cities of Brazil and in two cities of United States of America. Eligible participants will be then randomized and allocated (concealed allocation 1:1:1) in 3 groups: 1) early physical therapy with education (minimal intervention); 2) early physical therapy with education and exercise therapy; and 3) delayed physical therapy with education and exercise therapy. The program will be delivered using an online platform through a telerehabilitation modality. A hybrid approach will be used with non-supervised sessions delivered for patients followed by scheduled supervised meetings with one physical therapist (meetings once a week every 2 weeks). Participants allocated to the multimodal treatments will also receive, by mail, elastic bands to help the conduction of the exercises. Outcomes will be assessed during baseline (i.e., before randomization and allocation) and follow-up assessments will be performed immediately (week 12), and in 3, 6, and 12 months after treatment completion. For statistical analyses, a regression model using Generalized Estimating Equations will be performed for group-by-time comparisons and a 3-variable framework will be used for mediation analyses. At the end of this study, we expect to find that early physical therapy will be superior to delayed physical therapy for clinical and psychological outcomes of patients with PFP, but that early physical therapy with education will be equivalent to early physical therapy with education plus exercise.