J. Young1, S. Snodgrass2, J. Cleland3, D. Rhon4
1Bellin College, Green Bay, United States, 2University of Newcastle, Newcastle, Australia, 3Tufts University, Boston, United States, 4Baylor University, Fort Sam Houston, United States
Background: Physical therapy and exercise therapy are deemed core treatments for patellofemoral pain (PFP), and should be considered essential to initial management. Incidental findings on imaging studies are common, can lead to additional unnecessary tests, and the results rarely change management strategies, so routine radiographs are discouraged in most guidelines for non-traumatic knee pain. Still, radiographs are often ordered for PFP, despite limited evidence for their value in guiding treatment choices. Exercise therapy should be started as soon as is appropriately possible, and starting physical therapy earlier has been associated with improved outcomes and lower long-term costs for other musculoskeletal disorders. It is possible that the wait for imaging appointments and results creates a missed window of opportunity to otherwise start treatments with known efficacy. Additionally, this delay in treatment caused by unnecessary radiographs could potentially lead to worse outcomes, and even greater risk for chronicity or recurrence.
Purpose: The purpose of this study was to identify how the use of knee radiographs impacted the use and timing of exercise therapy and physical therapy in patients with PFP. A secondary objective was to determine if radiographic imaging was associated with having additional episodes of knee pain. The hypothesis was that initial knee radiograph use would delay the start of exercise therapy and physical therapy, and patients who received initial radiographic imaging would be more likely to have a recurrent episode of knee pain.
Methods: 26,633 individuals aged 18 to 50 diagnosed with PFP between 2010 and 2011 in the Military Health System received exercise or physical therapy. They were further categorized based on the presence and timing of knee radiographs. Utilization and timing of physical therapy, exercise and recurrence of knee pain was compared between groups (with and without initial radiographs). A negative binomial regression was used to calculate odds ratios with 95% confidence intervals.
Results: If radiographs were used, the odds of receiving exercise (OR = 0.56; 95% CI 0.53 to 0.60) or physical therapy (OR = 0.44; 95% CI 0.40 to 0.49) were significantly lower. The mean days to exercise was 14.2 (95% CI 12.8 to 15.9) with radiographs versus 7.1 (95% CI 6.4 to 7.9) without (p<0.001). The mean days to physical therapy was 14.1 (95% CI 11.4 to 17.4) with radiographs versus 5.1 (95% CI 4.2 to 6.3) without (p<0.001). The odds of recurrence were significantly greater if radiographs were used (OR = 1.17; 95% CI 1.15 to 1.20; P<0.001).
Conclusion(s): Knee radiographs reduced the odds of receiving exercise or physical therapy, delayed initiation of these interventions, and increased the odds of having an additional episode of knee pain. Routine use of radiographs for PFP can potentially cause harm by delaying appropriate treatment.
Implications: Patients who receive an early knee radiograph may start physical therapy or exercise therapy later or not be referred at all, which may increase their healthcare utilization and costs. This study provides evidence to support clinicians to advocate for the use of safe interventions, such as physical therapy or exercise therapy, before radiographs are required.
Funding, acknowledgements: N/A
Keywords: patellofemoral pain, exercise therapy, physical therapy
Topic: Musculoskeletal: lower limb
Did this work require ethics approval? Yes
Institution: Army Regional Health Command Central
Committee: Institutional Review Board
Ethics number: C.2016.048n
All authors, affiliations and abstracts have been published as submitted.
