Osteoarthritis (OA) is a clinical diagnosis, meaning that a diagnosis should be made primarily through a clinical examination by a doctor or a physiotherapist. As OA can affect a joint long before the disease is visible on an x-ray which is why a diagnosis is based on symptoms, risk factors, and medical history.  Sometimes OA is difficult to diagnose as symptoms such as pain, swelling and stiffness can vary over time. For symptoms to improve, worsen and then improve again is not uncommon, especially amongst patients with early stages of the joint disease. Many go weeks or even months with little to no symptoms before a flare-up.

An X-ray is often not necessary

Many believe that an X-ray is needed to diagnose OA, but the truth is that X-ray images can be misleading. Changes that in OA are visible on X-rays occur relatively late in the process. On the other hand, it is also possible to detect OA detected on an X-ray without experiencing any symptoms. Therefore, an X-ray picture is not always a good representation of the disease. However, in certain cases, it can be performed to rule out other diagnoses or to evaluate the appearance of the joint in later stages of the disease. Occasionally, a magnetic resonance imaging (MRI) scan is performed as it can detect OA earlier than an X-ray. However, MRI scans are mainly done on younger patients when the diagnosis is uncertain. The challenge with an MRI scan is that the procedure detects even the smallest of changes in the joint structure and it can thereby be difficult to determine whether these small changes have any clinical significance for the patient or are simply a normal part of aging. There is also the risk of incidental findings that may cause unnecessary concern for the patient.

Diagnosis based on medical history and symptoms

Unfortunately, the diagnosis of OA is still very often based on an X-ray examination. The issue with this is that many patients with symptoms yet no signs of OA on an X-ray image, do not commence treatment in time. According to the Swedish National Board of Health and Welfare's guidelines, an assessment of a person’s medical history and symptoms is sufficient for a diagnosis. It is important that OA is treated as early as possible as it gives a person more time to influence the course of the disease.