Analyzing the Interaction between Clinical, Neurophysiological and Psychological Outcomes Underlying Chronic Plantar Heel Pain: A Network Analysis Study

Plantar heel pain (PHP) is one of the most common foot pain conditions in adults. Several biological and psychological factors could be involved in chronic PHP in a complex matrix. However, reciprocal interactions between these factors are unknown. The aim of the present study was to use network analysis to quantify potential multivariate relationships between pain-related, function, clinical, mechanosensitivity, psychological, and health-related variables in individuals with PHP. Demographic (age, gender), pain-related (pain intensity), function, clinical (myofascial trigger points [TrPs]), mechanosensitivity (pressure pain thresholds), psychological (Beck Depression Inventory), and health-related variables (EQ-5D-5L) were collected in 81 PHP patients. Network connectivity analysis was conducted to quantify the adjusted correlations between the modeled variables and to assess their centrality indices. The connectivity network showed local associations between pain-related variables, foot function, and mechanosensitivity. Additionally, associations between quality of life, depression, and pain-related variables were found, while TrPs was associated with quality of life and mechanosensitivity. The node with the highest strength centrality was the worst pain intensity, while mechanosensitivity and worst pain intensity showed the highest closeness and betweenness centrality. This is the first study to apply network modeling to understand the connections between pain-related, function, clinical, mechanosensitivity, psychological, and health-related variables in PHP. The role of pain severity and mechanosensitivity is highlighted and supported by the network. Thus, this study reveals potential factors that could be the target in the management of PHP, promoting a comprehensive and effective therapeutic approach.