Page 13 - Imaging of Osteoarthritis and Rheumatoid Arthritis in Hand Joints
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 Joint diseases are a leading cause of pain and disability in developed countries, 1 with hand joint diseases having large impact on normal daily activities. Osteoarthritis (OA) and rheumatoid arthritis (RA) are two prevalent joint disease
of very different etiology, both affecting hand joints. The focus of this thesis lies
on improving knowledge of radiological imaging techniques to detect features of OA and RA in hand joints. The following introduction will describe these joint diseases, the radiological imaging techniques, and how these techniques are used to image the hand joints and these joint diseases. Followed by the aims and outline of this thesis.
Background of osteoarthritis and rheumatoid arthritis
Osteoarthritis is the most common joint disease worldwide. The prevalence of osteoarthritis increases with age, and 10-18% of people aged over 50 have osteoarthritis.1 Osteoarthritis occurs in the hand mainly in the distal interphalangeal (DIP) joints, the proximal interphalangeal (PIP) joints and the first carpometacarpal (CMC1)joint.2 Other joints often affected are the knees, hips, and joints of the spine. The exact mechanisms of OA are unclear, but the disease affects the whole joint. Key aspects are the degradation of the cartilage leading to cartilage destruction, low grade inflammation of the synovium, and involvement of subchondral bone.3, 4 With progression of disease, irregular outgrowth along the margin of the bone are created called osteophytes, probably because the body tries to reduce the stress on the bone by increasing the joint surface. Subchondral bone increases in cellularity and density, and can undergo cystic degeneration in advanced disease. While the joint degrades and gets inflamed, patients experience joint pain, and due to the bone remodeling the joint becomes deformed and loses range of motion.5 Research into disease- modifying osteoarthritis drugs (DMAODs) is ongoing, but a usable drug has yet to be found. Currently, no treatment is available to halt or cure OA.6 Treatment protocols for hand OA are focused on alleviating symptoms by subscribing pain medication, performing physiotherapy, and splinting of joints to decrease joint stress. In severe thumb base OA, joint surgery like trapeziectomy can be performed to alleviate symptoms and help restore some thumb movement.
Rheumatoid arthritis is the second most prevalent hand joint disease in the world. It is more prevalent in women and prevalence increases with age. The prevalence in women over 50 in Europe is 1- 2%.1 RA is a systemic auto-immune disease with an unknown cause, which mainly targets the joints. The joints in
General introduction

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