Knee injuries are among the most common musculoskeletal injuries affecting military personnel, accounting for 22% of limited duty profiles and an average of 53 limited duty days per injury in 2017 alone. Patellofemoral pain (PFP) is the most prevalent knee injury affecting Service members but has historically been considered an innocuous and self-limiting condition despite its high rate of persistence. Physical therapy is often the first line-of-defense for PFP management. Published data support the notion that adherence to evidence-based Clinical Practice Guidelines (CPG) improves outcomes 1) for patients, via greater improvements in pain and disability; 2) for providers, by supporting clinical decision making and practice efficiency; and 3) for healthcare systems, by reducing length of treatment, resource utilization, and costs. In 2019, the American Physical Therapy Association (APTA) published its first CPG for PFP management to better enable physical therapists to make evidence-based treatment decisions; however, there is limited evidence regarding the effectiveness of a collective, standardized CPG-adherent approach in clinical care. To evaluate whether patients with PFP who receive CPG-adherent care demonstrate superior outcomes as compared to patients receiving the current usual care, we will compare: (1) CPG-adherent care (intervention arm), wherein physical therapy care is provided according to the CPG "Decision Tree" recommendations for PFP management, to (2) Usual Care (UC; comparator arm), wherein care decisions are made by non-research physical therapists in alignment with current organizational and clinical practice standards in the Military Health System (MHS). This multisite, single-blind randomized controlled trial will include 440 active-duty Service members with PFP across four major MHS physical therapy facilities (i.e., Naval Medical Center San Diego, Naval Hospital Camp Pendleton, Brooke Army Medical Center, and Womack Army Medical Center). The sample will include Service members from the Army, Navy, and Marines, as well as both conventional and special operations forces. The co-primary outcomes include changes in two CPG-recommended outcome measures \[Anterior Knee Pain Scale (AKPS) and the Numeric Pain Rating Scale (NPRS)\]. Outcomes will be assessed at baseline; 6-weeks post-randomization; and 3-, 6-, and 12-months post-randomization (primary endpoint: 3-months). Secondary outcomes will include between-group differences in confidence with completing duty-related tasks and 12-month analgesic medication prescription and PFP-specific medical resource utilization. An exploratory analysis will seek to determine the predictors and mediators of clinical benefit from physical therapy care for Service members with PFP. Baseline and follow-up assessments will be administered remotely to maximize participant reach and retention. The intervention of interest, CPG-adherent care, is designed to be clinically feasible, with high potential for clinician adoption, which may improve care quality and patient outcomes for Service members with PFP. Long-term, findings from this study have the potential to improve patient care for PFP and other musculoskeletal injury conditions across the MHS by demonstrating the feasibility and positive impact of CPG-adherent care, particularly in terms of improving clinical outcomes and resource utilization and reducing unwanted variability in rehabilitation.
