Abstract/Summary

Knee osteoarthritis(OA) is the most common form of OA and mild-to-moderate OA. Patients who do not respond to conversative treatment or yet warrant joint replacement represent a significant clinical challenge. Genicular Arterial Embolisation(GAE) is a promising interventional radiological technique for OA. However, data highlight a consistent subset of patients that do not respond to GAE, despite a successful procedure. Pain Catastrophising(PC) represents a set of cognitive/affective biases to pain, linked to maladaptations in the descending pain modulatory system and has been frequently identified as a predictor of clinical outcomes. This study investigated the association between PC and GAE outcomes and underlying neural correlates, using resting-state functional magnetic resonance imaging. Thirty patients participated in a presurgical assessment battery, including psychometric profiling and quantitative sensory testing. Due to MR exclusions, a subset of seventeen patients also completed an rs-fMRI session. Patients recorded their outcomes at 6-weeks, 3-months and 12-months. The dorsolateral prefrontal cortex(DLPFC) served as a seed for whole-brain voxel-wise connectivity, with pain catastrophising scores as a regressor. PC was associated with a myriad of psychological/lifestyle baseline variables, such as depression, anxiety and poor sleep. Surprisingly, high pain catastrophisers demonstrated the best improvements, with PC scores predicting the higher reductions in pain at 6-weeks(R2=.18,p=.024), 3-months(R2=.37,p<.001) and 1-year(R2=.18,p=.027). Resting-state analyses revealed that catastrophising was associated with higher connectivity between the DLPFC and areas of the brain associated with pain processing, suggesting more frequent engagement of top-down modulatory processes. These results highlight that, interestingly, patients who catastrophise may benefit most from GAE. Potential explanations for this are discussed within. Overall, this data indicates GAE is an effective treatment for knee OA, and may be valuable at managing pain for high catastrophisers, who often fare worse in more invasive surgical procedures.