Abstract
Background:
Patellofemoral pain (PFP) is a chronic knee condition that affects over 1 in 4 physically-active girls. PFP symptomology contributes to dysfunctional motor control and heightened kinesiophobia (i.e., fear of pain/movement). Both chronic pain and kinesiophobia induce substantial changes throughout the central nervous system (CNS) in many populations who experience pain (e.g., low back pain), but such relationships have not been explored in pediatric patients with PFP. As current treatment approaches for PFP generally fail to provide complete symptom mitigation, identifying the mechanisms by which kinesiophobia exacerbate PFP and disrupt the CNS could provide mechanistic neural pathways to guide novel, brain-based treatments for pain relief.
Hypothesis/Purpose:
The purpose of this study was to determine the relationship between kinesiophobia and brain functional activation during a knee motor control task in pediatric patients with PFP.
Methods:
Girls clinically diagnosed with PFP (n = 15; 14.3 ± 3.2 yrs) were positioned supine in a 3 Tesla magnetic resonance imaging (MRI) scanner and completed a series of unilateral 45° knee extension/flexion movements during functional MRI (fMRI). Patients completed this open kinetic chain movement at a frequency of 1.2 Hz (Figure 1.1). Patients also completed the Tampa Scale of Kinesiophobia (TSK; scores range from 0 – 68, with scores greater than 37 indicating high kinesiophobia). Correlation analyses were performed to determine whether kinesiophobia was associated with brain activity during the motor task. Statistical corrections were made to account for multiple, voxel-wise comparisons.
Results:
Study patients exhibited high kinesiophobia, with a mean TSK score of 38.27 (SD = 5.79). Neuroimaging analyses revealed that greater kinesiophobia was directly associated with increased brain activity in a cluster located within the occipital pole/cuneus, supracalcarine cortex, and intracalcarine cortex (p < .001, z-max = 4.30; Figure 1).
Conclusion:
The results revealed that the degree of kinesiophobia was related to the magnitude of visual-related brain activity for knee motor control. As perceived fear of movement increases, patients with PFP may recruit additional visual resources to compensate for pain-disrupted somatosensory processing. Future interventions that promote sensorimotor engagement and reduce visual feedback for motor control (i.e., dynamic movements with occluded vision) may be beneficial to reorganize neural processes, decrease kinesiophobia, and restore an active lifestyle in young girls with PFP.
Tables/Figures:
Left: participant demonstrating the knee flexion/extension movement. Right: Greater kinesiophobia was associated with increased visual-related brain activity (yellow/orange clusters) during the open kinetic chain movement for patients with PFP.