Level of physical activity of individuals with patellofemoral pain and their associations with biomechanical, clinical and psychological parameters: a prospective study

Abstract

Patellofemoral pain (PFP) characterized by the presence of peri or retro patellar pain, of insidious onset, exacerbated during weight support activities involving knee flexion which overload the patellofemoral joint, being one of musculoskeletal disorders of lower limbs more frequent in orthopedic and sports practice. Some factors have been pointed out as the key mechanism for the development and chronicity of pain, with a focus on biomechanical alterations and lower limb muscle imbalances that compromise the movement pattern, however, the level of physical activity and overuse also seem to contribute to the development and/ or exacerbation of symptoms. In this sense, the physical activity level is an important factor to be considered in people with PFP, since modifications such as an abrupt increase or reduction on physical activity levels may be associated with increased of pain, kinesiophobia and a greater number of biomechanical changes in this population. Cross-sectional studies investigated the association between the physical activity level and the intensity of symptoms and the association between physical activity level with psychological and biomechanical parameters. However, to date, there are no longitudinal studies that have evaluated changes in physical activity levels in people with PFP and its association with these parameters. The aim of this project is to investigate whether individuals with PFP modify their physical activity levels over time and to verify the possible relationship between these changes and biomechanical, clinical and psychological parameters after 24 months. This is a prospective study, which will monitor men and women with PFP over 24 months period. Data will be assessed at two different times, initial assessment (baseline), previously collected between 2018-2019, and a second evaluation after 24 months (follow-up). The sample will be composed by 104 participants, 37 men and 67 women. Data collection will be divided into two steps that will be carried out on different days: (1) assessment of the level of physical activity (Baecke's Habitual Physical Activity Questionnaire), assessment of clinical and psychological parameters (Visual Analog Pain Scale (VAS), Anterior Knee Pain Scale (AKPS), TAMPA Scale, Pain Catastrophizing Scale) and biomechanical evaluation during the step down test (using a three-dimensional movement system); (2) evaluation of muscle function - maximum torque, torque development rate and strength stability (using the isokinetic dynamometer). The statistical analysis will compare the two periods, initial assessment (baseline) and after 24 months (follow-up) using the Student's T test for independent samples or the Mann-Whitney U Test, depending on the data distribution. Subsequently, the variables will be inserted in the correlation model, the difference in the physical activity levels detected between the two periods (baseline - follow-up = ”) and the variables related to the biomechanical, clinical and psychological parameters after 24 months will be analyzed. The Pearson (r) or Spearman correlations tests will be used, depending on the data distribution. Finally, the data will be inserted in a linear regression model, the independent variable analyzed will be the difference in the physical activity levels detected between the periods (”) and the dependent variables will be related to biomechanical, clinical and psychological parameters. The level of significance adopted will be ± <0.05. (AU)