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Osteoporosis, Arthritis, and DEXA Scans: Does a DEXA Scan Show Arthritis?

This article explains the difference between osteoporosis and arthritis and whether a DEXA scan can show arthritis.

Written by Chelsea Okonkwo
Last updated 18 Jun, 2024

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As we age, our musculoskeletal system, which provides structure, support, and protection, naturally experiences degeneration and can be compromised by two common conditions: osteoporosis and arthritis. If you are experiencing symptoms that make you wonder if either of these conditions might be the cause, you've landed on the right resource.

In this article, we clearly define osteoporosis and arthritis and explain their differences. We also explore the symptoms of each condition to help you identify which one might be affecting you. Finally, you'll learn about the diagnostic process for both conditions, including the tests such as DEXA, X-rays, MRI, and ultrasound scans needed for accurate diagnosis, so you are empowered to seek the appropriate medical attention.

What is the difference between osteoporosis and osteoarthritis?

Your bones are living tissue consisting of 35% protein and 65% minerals such as calcium, phosphorus, and sodium. They are constantly maintained by a remodelling process, where old bone tissue is broken down and replaced with newly formed, healthy tissue. As you age, particularly past 40 years, there can be an imbalance causing bones to be broken down faster than they can be replaced. Osteoporosis can occur if this imbalance causes a significant loss of the bone’s mineral content.

Osteoporosis is caused by dangerously low bone mineral density or mass. It is characterised by bone weakness, fragility, and increased susceptibility to fractures (broken bones).

Unlike osteoporosis, arthritis is a disease of the joints. There are more than 100 types of arthritis. Osteoarthritis is the most common type, primarily affecting people aged 45 and older. Osteoarthritis is also called a degenerative joint disease or wear-and-tear disease. Here's why:

Every bone in the human body, except the hyoid bone at the base of the tongue, is connected to another at a joint. The ends of the bones that meet to form a joint are covered by a layer of flexible tissue called articular cartilage, which allows the two bones to glide smoothly against each other during movements.

However, not all joints facilitate movement. There are joints, namely fibrous (fixed) and cartilaginous joints, that don’t allow a full range of motion. But as we talk about osteoarthritis, we’ll be referencing the synovial joint (otherwise called a freely movable joint), found in places where mobility is necessary, such as the shoulder, elbow, wrist, hands, fingers, knees, and hips. In the synovial joint, there is usually a thick, slippery fluid between the two connecting bones called the synovial fluid.

Like bones, the articular cartilage is maintained by a remodelling process, which involves the continuous breaking down of old tissue and the production of new, healthy tissue. With age and several risk factors, the rate at which this process occurs slows down, and the old cartilage wears out faster than new cartilage can be made.

Osteoarthritis is characterised by an imbalance between the wearing down of cartilage and the slowed production of new cartilage. It commonly affects the joints in the knees, hips, hands, and lower back.

It’s important to note that both osteoporosis and osteoarthritis can occur at the same time. Let’s move on to explore their symptoms.

Symptoms of osteoporosis

There are usually no symptoms of osteoporosis until a fracture (broken bone) occurs. Osteoporotic fractures commonly occur in the spine, hip, or neck. When an osteoporotic fracture occurs in the spine, it can cause any of the following symptoms: 

  • Stooped or hunched posture (kyphosis)

  • Severe back pain

  • Height loss

If a fracture occurs in the hips, you might experience pain, stiffness and discomfort in the hip, groin, or buttocks area that worsens with weight-bearing activities.

Symptoms of osteoarthritis

It is important to note that some people with osteoarthritis may be asymptomatic, even if imaging scans clearly show joint changes indicative of the condition. When symptoms do appear, they may include:

  • Pain in the affected joint(s) that worsens during or after activity—or in the more advanced stages of the disease—at nighttime. This pain might be dull, burning, or throbbing.

  • Stiffness in the joint, especially in the early morning upon waking or during the day after several hours of inactivity.

  • Swelling in or around the affected joint(s).

  • Reduced function of the affected joint, resulting in a limited range of motion.

Is osteoporosis arthritis?

No, arthritis and osteoporosis are not the same condition. Although both are bone diseases, they don’t develop or present in the same way, nor are they diagnosed or treated using the same methods.

Osteoporosis is marked by severely low bone mineral density and mass, often progressing without causing any symptoms until a bone is broken. In contrast, arthritis is a disease of the joints with more noticeable symptoms, including joint pain, swelling, stiffness, and reduced mobility and function.

Which is worse: osteoarthritis or osteoporosis?

Both osteoporosis and osteoarthritis are chronic, long-term conditions that cause painful symptoms ranging from mild to severe. They affect the body in different ways, and the impact on a person's life depends on factors such as the location of the affected joints and the degree of bone loss. We can’t definitively say which condition is worse since experiences with either are unique. However, many would argue that osteoporosis is worse than osteoarthritis because it gradually weakens the bones without showing any symptoms until a fracture (broken bone) results from a minor fall, coughing, or even sneezing. This is why osteoporosis is often called a silent thief. Although, there are early warning signs of osteoporosis that are subtle and easily missed. 

You can read more about these signs here: Osteoporosis Symptoms: What Are the Early Warning Signs of Osteoporosis?.

Osteoporosis vs arthritis: how are they diagnosed

The diagnostic process of both arthritis and osteoporosis typically starts with a thorough review of a patient’s medical and family history. Your healthcare provider may ask questions about your symptoms, such as when they first appeared and whether specific factors worsen or lessen your pain. Also, you may be required to share information about any past injuries or fractures, current or past medical conditions and medication use, your lifestyle habits, the health conditions of select family members, and, if you are a woman, your menstrual history.

Next, your provider may perform a physical exam, which can involve touching your joints to assess your pain level and observe any stiffness or swelling, in addition to checking your reflexes, balance, and muscle strength, changes in posture, and a height reduction greater than 1.5 inches (~4 cm).

In a suspected case of osteoporosis, your provider may proceed by ordering a dual-energy X-ray absorptiometry (DXA or DEXA) scan. A DEXA scan is a non-invasive and painless imaging test that uses low-dose X-rays—much lower than a standard X-ray test—to measure how dense your bones are in a specific body part, usually the ones prone to osteoporotic fractures, such as the hips and spine. It is also called a bone density test.

With its considerably high sensitivity (detection) and specificity (accurate identification) rate, a DEXA scan is the gold standard for diagnosing osteoporosis. It also helps to detect pre-osteoporosis (osteopenia), predict the risk of future fractures, and monitor the effectiveness of ongoing treatment.

A DEXA scan is relatively quick and requires no special preparation. After the test measures the mineral content in your bones, the results are compared to the average bone density of a healthy young adult to derive a number called a T-score. If you are a premenopausal woman or a man younger than 50, your bone density will be compared to the average of healthy people your age, gender, height, weight, and ethnicity, resulting in a Z-score.

If your Z- or T-score is:

  • -1.0 and higher, your bones are healthy.

  • -1.0 to -2.4, you have osteopenia.

  • -2.5 and lower, you might have osteoporosis. We say ‘might’ because a low bone density score may also represent other metabolic bone diseases such as osteomalacia (soft bone disease) and Paget’s disease of the bone. Therefore, your provider may likely order further testing for a confirmative diagnosis.

How is arthritis diagnosed?

Since there are many different types of arthritis and it’s possible to have more than one present at the same time, the diagnostic process may involve several additional tests. Your provider may proceed with:

  • Laboratory tests. These tests involve the collection of blood or urine samples to check for biomarkers (e.g., proteins, antibodies, and blood cell count) that may indicate inflammation, autoimmune disorders, and infections associated with arthritis.

  • Arthrocentesis (also known as joint aspiration). It is a procedure that involves using a thin needle and syringe to extract synovial (joint) fluid for a comprehensive analysis. 

  • Imaging scans. They give detailed visuals of what’s happening to your joints. The most commonly used imaging tests for arthritis include:

  • X-rays. X-rays use low-dose radiation to produce detailed, two-dimensional (2D) images of dense internal organs, mainly bones. They help show bony changes indicative of arthritis. These changes may be the narrowing or complete loss of the joint space between two connecting bones, the presence of osteophytes (bone spurs), subchondral sclerosis (an increase in the density or thickness of the bone directly under the cartilage), and subchondral cysts (a small, fluid-filled sac that forms under the layer of cartilage in one or both bones that make up a joint). However, an X-ray test may not be sensitive to the early stages of osteoarthritis, which usually involves cartilage loss, as it is less effective on soft tissues. 

  • Ultrasound. An ultrasound scan uses high-frequency sound waves to visualise different organs and tissues inside the body. It is not often used to diagnose arthritis because it can’t properly assess bony structures. However, it may be used when there is noticeable joint swelling to observe joint effusion (excess fluid buildup in the joints). It can check the synovial membrane lining the joint for cysts and inflammation and also evaluate surrounding structures, such as ligaments and tendons.

  • Magnetic resonance imaging (MRI). An MRI scan uses a strong magnetic field and radio waves to generate detailed, three-dimensional (3D) images of the body’s internal organs, including the bones, joint space, and soft tissue joint structures (such as cartilage, muscles, and nerves) affected by arthritis. It can visualise all the characteristic features of arthritis and is highly sensitive to early arthritic changes that X-rays and an ultrasound might miss. 

Does a DEXA scan show arthritis?

If you’re wondering: ‘Does a bone density test show arthritis?’ The answer is no! A DEXA or bone density scan doesn’t show arthritis. It can’t provide a detailed image of the joint and isn’t sensitive enough to detect arthritic changes in bones or soft tissues. For diagnosing arthritis, imaging tests like X-rays, MRI, ultrasound, or CT scans are more appropriate as they can visualise joint spaces, bones, cartilage, and soft tissue structures.

Conclusion

We’ve discussed the difference between arthritis and osteoporosis, explained their diagnostic processes, and answered the question: Does a bone scan show arthritis?

If you're now wondering about your next steps, we recommend you book a DEXA scan for osteoporosis diagnosis or check our MRI, ultrasound and X-ray scans, which can all be used to assess arthritis. Scan.com is the UK's largest imaging network, with over 150+ scanning centres nationwide. You can browse through locations near you, compare prices, and book the earliest appointment time, all in a matter of minutes. Skip NHS waiting lists. No GP referral needed. No hidden costs.

Not sure which test to choose? Book a consultation for £50 for expert clinician advice and a no-obligation referral to the scan best suited to your unique concerns. 

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