M. Pazzinatto1,2, C. Barton2,3, R. Willy4, A. Ferreira1, F. Azevedo1, D. De Oliveira Silva2
1Sao Paulo State University, Physiotherapy, Presidente Prudente, Brazil, 2La Trobe University, La Trobe Sports and Exercise Medicine Research Centre, Melbourne, Australia, 3University of Melbourne, Department of Surgery, St Vincent’s Hospital, Melbourne, Australia, 4University of Montana, School of Physical Therapy and Rehabilitation Sciences, Missoula, United States
Background: Strong evidence from cross-sectional studies indicates high levels of fear of movement and impaired physical function exists in women with patellofemoral pain. Both features are related to pain, disability and prognosis in this population, but it is unclear how they might relate to development of patellofemoral pain over time.
Purpose: To determine whether fear of movement and physical function are (i) prospectively associated with the risk of developing patellofemoral pain; or (ii) change following development of patellofemoral pain.
Methods: Uninjured women (n = 114) with no previous history of lower limb injury completed assessment of the following outcomes at baseline and 2-year follow-up: (1) fear of movement using the TAMPA Scale for Kinesiophobia; (2) physical function (forward step-down test, single leg hop for distance). Participants also completed questionnaires regarding their knee health status every 3-months, and if they reported knee pain, were immediately invited to attend the university's clinic for a clinical assessment. Patellofemoral pain was diagnosed following detailed clinical examination performed by a physical therapist, based on international patellofemoral pain consensus recommendations. The study was approved by the Sao Paulo State University Human Ethics Committee, and all participants provided written informed consent (number: 2.513.406). Logistic regression models were used to explore the association between outcomes at baseline and the development of patellofemoral pain. Independent t-tests were used to compare the group that developed patellofemoral pain with the pain-free group at 2-years follow up.
Results: Ninety participants completed the 2-year follow up assessment (retention rate 79%), with 27 (24% of the study cohort) developing patellofemoral pain. Fear of movement and objective physical function were not associated with the risk of developing patellofemoral pain (r2 range from 0.003 to 0.05; p-value > 0.122). Participants who developed patellofemoral pain had impaired physical function compared to those who remained uninjured at 2-years follow-up, presenting a reduction of 17% on the forward step-down test (mean difference = 3; p-value = 0.033) and 11% on the single leg hop for distance (mean difference = 9.01; p-value = 0.018). Fear of movement was not different between groups at the 2-years follow up (mean difference = 3.19; p-value = 0.095).
Conclusion(s): Fear of movement and physical function are not risk factors for the development of patellofemoral pain in young women. In a short-term following patellofemoral diagnosis (< 2 years), impairments in physical function but not in fear of movement could be observed. Future studies are needed to explore other factors which may provide insight into risk factors for patellofemoral pain.
Implications: Screening for fear of movement and physical function does not appear to be an effective means to identify young women at risk for developing patellofemoral pain.
Funding, acknowledgements: To São Paulo Research Foundation (FAPESP) for a scholarship to MFP (2016/19784-0).
Keywords: Kinesiophobia, Anterior knee pain, Function
Topic: Musculoskeletal: lower limb
Did this work require ethics approval? Yes
Institution: Sao Paulo State University
Committee: Sao Paulo State University Human Ethics Committee
Ethics number: 2513406
All authors, affiliations and abstracts have been published as submitted.
