A diagnosis of osteoarthritis is usually drawn based on the clinical presentation of symptoms and taking a medical history. It can then be confirmed with X-ray imaging of the affected joints.
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Symptoms usually present with swollen joints, often in the hands but may also affect the spine, hips, knees, feet as well as other joints in the body. The affected areas are often associated with stiffness and distinctive pain.
As a result of these symptoms, many people who suffer from the condition have difficulty completing everyday tasks, particularly in later stages as the severity of the disease progresses. This is because the freedom of movement of the joints is greatly affected.
Confirmation with X-ray
Confirmation of the diagnosis can be made with X-ray imaging by observing the typical changes associated with osteoarthritis. It is common to see a narrowing of spaces in the joints, increased formation of bone around joints (also known as subchondral sclerosis), cyst formation and osteophytes. It is worth noting that plain films do not always correlate precisely to the physical presentation or reported degree of pain.
In most cases, other types of imaging techniques are not required to make an accurate clinical diagnosis of arthritis and X-ray imaging alone is sufficient.
In 1990, a set of criteria to be used in the diagnosis of osteoarthritis of the hands was developed by the American College of Rheumatology. It was based on a multi-center study and used hard tissue enlargement and swelling of certain joints to indicate osteoarthritis.
These criteria where found to be a highly effective way to distinguish osteoarthritis from other conditions with 92% sensitivity and 98% specificity.
Pseudo-arthrosis is another health condition that has similar characteristics to osteoarthritis, increasing the possibility of misdiagnosis. Radiographic imaging can help to differentiate osteoarthritis from this, which should depict the degenerative pathology of the distal phalangeal joints. Eburnation refers to a change in the affected joints involving a polished ivory-like development on the associated bones.
Classification by severity
There are two classification systems that may be used to define the severity of the condition: the WOMAC scale and the Kellgren-Lawrence grading scale.
The WOMAC scale is the most widely used and involves measures of pain, stiffness and functional limitation to determine the overall severity of an individual’s condition. Each measure is self-reported, so depends on the individual’s response to pain and body dysfunction. It is, however, a very useful tool in helping to understand the impact of osteoarthritis on an individual’s life and give an indication as to the place and efficacy of treatment.
The Kellgren-Lawrence grading scale is another alternative, which assesses the severity of knee osteoarthritis based on a plain audiograph. The scale ranges from 0 (no signs) to 4 (severe bone deformity).
Classification by cause
Classification of osteoarthritis can also be made according to whether it results from an identifiable underlying cause.
Primary osteoarthritis refers to when symptoms present without an obvious cause. Both generalized nodal and erosive osteoarthritis are sub-sets of primary osteoarthritis. The erosive type is rare but particularly aggressive and often affects the distal inter-phalangeal joints of the hand, which is evident on inspection of X-ray images.
Secondary osteoarthritis occurs as a result of another cause. There are several health conditions that may lead to symptoms of osteoarthritis such as obesity, diabetes and inflammatory disorders.