Neuropathic-like symptoms in hip and knee osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis. It is characterized by degeneration of the joint. Typical symptoms are joint pain, stiffness and deficits in joint function. Around 10% of men and 18% of women aged over 60 have symptomatic OA. Around 20% of the hip OA and 20-67% of the knee OA patients experience neuropathic pain-like symptoms like tingling and burning sensations. These neuropathic-like symptoms are likely a proxy for a more sensitized pain system. The overall aim of this thesis was to further elucidate the role of neuropathic-like symptoms in symptomatic OA of the hip and knee. Furthermore is was studied whether neuropathic-like symptoms could be treated to reduce experienced pain. In this thesis it is described that OA patients with neuropathic-like symptoms experienced diminished joint function and a lower quality of life. Moreover it was seen that more pain was experienced one year after total hip/knee replacement when patients experienced neuropathic-like symptoms preoperatively. This suggests that an established more sensitized pain system (preoperatively) could still be present after joint replacement. Finally this thesis describes the results of a study that investigates the addition of the medicine duloxetine in the period before total hip/knee replacement in highly symptomatic patients that experienced neuropathic-like symptoms. The results showed that duloxetine was effective in knee OA patients in terms of pain relief, but not in hip OA patients. Future research is needed to elucidate these findings.