The predictive role of pain catastrophising following genicular arterial embolisation for the treatment of mild and moderate knee osteoarthritis

Knee osteoarthritis (OA) is the most common form of OA and is not currently considered to be a curable disease. Specifically, mild-to-moderate knee OA that is resistant to conservative treatment, but does not warrant joint replacement, poses a significant clinical problem. Genicular arterial embolisation (GAE) is an interventional radiological technique designed to subvert neoangiogenesis within the joint, in turn reducing pain and improving function. Preliminary data has identified a subset of patients who do not respond, despite a technically successful procedure. We therefore investigated individual differences in pain and pain perception to identify predictive pre-surgical markers for clinical outcomes. Specifically, we investigated pain catastrophising (PC) and its neural correlates using resting-state functional magnetic resonance imaging (rs-fMRI). Thirty patients participated in a presurgical assessment battery during which they completed psychometric profiling and quantitative sensory testing. A subset of seventeen patients also completed an rs-fMRI session. Patients then recorded post-surgical outcomes at 6-weeks, 3-months, 12-months and 24-months. The dorsolateral prefrontal cortex (DLPFC) served as a seed for whole-brain voxel-wise connectivity with pain catastrophising scores entered as a regressor in group analysis. Pain catastrophising was associated with a myriad of aversive psychological/lifestyle variables at baseline, as well as a predisposition for attending to pain. Surprisingly, high pain catastrophisers stood to gain the best improvements from GAE, with PC scores predicting the higher reductions in pain across all time-points. Seed-based whole-brain connectivity revealed that PCS 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 when experiencing pain. These results are an early step towards understanding outcomes from novel interventional treatments for mild-to-moderate knee OA. Data suggests that improvements in pain and function via GAE could help high catastrophisers manage their pain, and in turn, the negative associations with pain that were identified at baseline.