Clinical, Psychological, and Neurophysiological Outcomes Associated with Pain and Function in Individuals with Unilateral Plantar Heel Pain.

OBJECTIVE: To assess the potential relationship of demographic (age, gender, body mass index, height, weight), clinical (affected side, duration of symptoms, health-related quality of life), psychological (depressive levels), or neurophysiological (pressure pain sensitivity and number of trigger points) variables with foot function and pain intensity in patients with unilateral plantar heel pain (PHP). METHODS: Fifty-four patients with PHP (48% females) were recruited. Data on demographics, months with pain, time in standing position, depression, pressure pain thresholds (PPTs), number of trigger points, health-related quality of life, function, and pain intensity were collected. A multivariable correlation analysis was performed to determine the associations among the variables, and a regression analysis was conducted to explain the variance in function and pain intensity. RESULTS: Pain intensity was negatively correlated with symptom duration and calcaneus bone PPT and positively associated with gender, time in standing position, and number of trigger points. Function was negatively correlated with PPTs on the calcaneus bone, the flexor digitorum brevis muscle, and the abductor hallucis muscle and with quality of life and was positively correlated with age, gender, and depressive levels. Stepwise regression analyses revealed that 60.8% of pain intensity was explained by female gender, calcaneus PPTs, time in a standing position, and function. Furthermore, gender, quality of life, age, depressive levels, and calcaneus bone PPTs explained 52.4% of function variance. CONCLUSIONS: This study found that demographic, clinical, psychological, and neurophysiological variables can mutually interact to affect function and pain intensity in patients with unilateral PHP. These findings could guide clinicians in the identification, prevention, and treatment of PHP risk factors.