Are Genicular Nerve Blocks Effective in Predicting Positive Radiofrequency Ablation Outcomes?
According to the National Health Interview Survey, over 51 million people were diagnosed with arthritis in 2010 (1). Osteoarthritis (OA) encompasses a significant proportion of arthritis sufferers, affecting over a third of the population over 65 years old (2). Osteoarthritis is a progressive degeneration of both the joint cartilage and subchondral bone (3). Although OA can affect any joint, it most commonly manifests in the hands, knees, hips, and facet joints of the spine. Of these affected locations, knee osteoarthritis has the highest incidence with 240 cases per 100,000 person years (4). Treatments include both surgical and non-surgical options (lifestyle modifications, NSAIDS, intra-articular corticosteroid injections, viscosupplementation). Total knee arthroplasty is the gold standard for surgical treatment, however 15-30% of patients who have undergone surgery may continue to experience pain and functional limitation (3). For patients who have failed to improve following these options, radiofrequency ablation (RFA) has been observed to be a safe and beneficial treatment (3,5). RFA studies have reported significantly improved patient reported VAS scores at 4 and 12 weeks post-ablation with no harmful side effects reported (3,5). Prior to proceeding with a radiofrequency ablation, genicular nerve blocks (GNB) with local anesthetic are performed under fluoroscopic guidance to predict whether or not patients will have a positive outcome from the ablation.