Osteoarthritis: The Disability Epidemic

The ability to move pain-free is one of life’s greatest privileges. Unfortunately, osteoarthritis can take that away; it is the leading cause of work disability, affecting 57.3% (32.5 million) of American adults.

On top of that, one out of every five patients with osteoarthritis experiences depressive symptoms. This further affects their physical, social, and financial well-being.

With that said, managing osteoarthritis is simpler than you may think (without resorting to surgery). The process begins, though, by learning more about it.

Seen (and Unseen) Osteoarthritis Suffering

• One-fourth of affected adults report constant severe pain (usually a seven in intensity on a ten-point scale).
• For 10% of patients, the pain is so severe that it confines them to their beds.
• Up to 60% of patients with osteoarthritis report being unable to work full-time.
• Osteoarthritis prevalence has risen 113.25% in the past two decades, with direct medical expenses amounting to $303.5 billion USD annually.
• 60% of patients with osteoarthritis experience mental health issues.

What is Osteoarthritis and The Science Behind It?

Osteoarthritis refers to a joint degenerative process. Normally, cartilage (specifically hyaline cartilage) and fluid (namely synovial fluid) help lubricate and reduce friction between the bones that comprise a joint.

Damage to the hyaline cartilage sets off an inflammatory cascade that reduces synovial fluid production and damages cartilage-producing cells (chondrocytes). This increases bone friction, leading to bone remodeling (scarring and overgrowth) and degeneration.

What Joints are Affected by Osteoarthritis?

Osteoarthritis commonly affects weight-bearing joints (given their susceptibility to wear and tear) and other joints prone to injury. These include (percentage in brackets refers to the frequency of joint involved):

• Knee joint (26.7%)
• Hip joint (18.5%)
• Distal (35%) and proximal interphalangeal (18%) joints
• Thumb joint (1.4%)
• Cervical (13.76%) and lumbar vertebrae (27-37%)
• 1st metatarsophalangeal joint (13.5%)

Types of Osteoarthritis

There are two types of Osteoarthritis: Primary and secondary.

Primary Osteoarthritis and its Risk Factors

Primary osteoarthritis refers to joint degeneration without any history of trauma or a known medical cause. It primarily affects large weight-bearing joints (such as the knee and hip) and has many risk factors:

• Age: Osteoarthritis predominantly affects individuals aged 65 and over. In addition, its prevalence increases with age. In other words, osteoarthritis affects 33% of individuals aged between 60 and 70 years and 43.7% above 80 years. This is because of the age-related increase in inflammatory mediators (especially interleukin-6) and subsequent cartilage degeneration.
• Genetics: Studies show that 60% of hip osteoarthritis (and 38% of knee osteoarthritis) patients share a common gene.
• Body weight: A study, including 1.7 million participants, found that individuals with a BMI (body-mass index) greater than 35 were 5 times more likely to develop osteoarthritis than people with a normal BMI. This is because of the increased production of pro-inflammatory chemicals (such as leptin and adiponectin) that deteriorate joint integrity.
• Repetitive movements: Individuals who repeatedly perform a similar set of movements (for example, construction workers) are more likely to develop osteoarthritis. This is because repetitive stress triggers the release of dangerous chemicals (reactive oxygen species) that kill chondrocytes (cartilage-producing cells).
• Muscular weakness: Studies show that muscle wasting (and weakness) greatly increases the risk of developing osteoarthritis. This is because the weakness creates joint instability, which understandably raises injury risk.

Secondary Osteoarthritis and its Causes

Secondary osteoarthritis is joint degeneration due to a known medical cause, for example:

• Congenital joint abnormalities: Up to 45% of individuals with hip dysplasia or scoliosis develop osteoarthritis. Understandably, this is because of joint misalignments that create undue stress.
•  Joint trauma or surgery: Up to 38% of patients who undergo surgery for traumatic joint injury develop osteoarthritis.
• Hormonal imbalance: Hormones such as growth hormone (by promoting bone growth) and estrogen (through its bone protective properties) affect joint integrity and structure. This is why patients with hormonal imbalances (e.g., those with diabetes) are more likely to develop osteoarthritis.
• Storage disorders: Excess joint mineral deposition (for example, iron in hemochromatosis or copper in Wilson’s disease) triggers a massive inflammation reaction that leads to bone (and, as a result, joint) degeneration. Unsurprisingly, 72.4% of patients with hemochromatosis and 86% with other storage disorders develop osteoarthritis.
• Inflammatory arthritis: Other pro-inflammatory joint disorders, such as gout and rheumatoid arthritis, for obvious reasons, can cause osteoarthritis. 
• Infections: Joint infections can cause inflammation and subsequent joint degeneration (i.e., osteoarthritis).

Osteoarthritis Treatment: Is It Curable?

Many osteoarthritis treatment options exist. Let’s discuss these further.

Exercise, Diet and Physical Therapy: First-Line Treatment for Osteoarthritis

• Exercise — A large meta-analysis of 48 trials shows aerobic exercise can reduce pain and improve mobility in patients with osteoarthritis. This is because it triggers the release of feel-good hormones (endorphins).
• Tai Chi — For the same reasons (as exercise), a trial including 40 patients with osteoarthritis reported significant improvements in quality of life with Tai Chi. Another systematic review of 7 trials corroborated these results. 
• Knee taping — A systematic review of 7 clinical trials found that knee taping (by alleviating joint stress) reduces pain (particularly after walking) and increases joint range of motion in patients with osteoarthritis. For some patients, this effect is comparable to taking pain medications.
• Physical therapy — A systematic review, including 730 participants, showed significant pain and mobility improvements in patients with osteoarthritis receiving physical therapy (owing to its muscle strengthening and joint biomechanic restoration effects).
• Weight loss — Weight loss (by reducing joint stress) reduces the risk of developing osteoarthritis and improves outcomes in patients with osteoarthritis.

Medical Therapy for Osteoarthritis: Second-Line Treatment

Doctors recommend acetaminophen (Tylenol) as the initial medical treatment for osteoarthritis. This is because it’s safe to use and helps relieve pain. For the same reasons, topical pain medications are a great option. For example, 47,113 patients with osteoarthritis, in an analysis of 122 trials, reported pain relief with acetaminophen and topical medication.  

NSAIDs (Non-steroidal anti-inflammatory drugs), the next line of medical treatment, offer more significant pain relief and quality of life improvements than acetaminophen. However, they also increase the risk of gastrointestinal discomfort.

For patients who do not respond to acetaminophen or NSAIDs, a doctor may try:

• Tramadol (a synthetic opioid): A study on 1,020 patients showed that it can significantly relieve pain and improve sleep quality.
• Duloxetine (an antidepressant, specifically an SSRI); A systematic review including 2,102 patients with osteoarthritis reported significant improvements in pain, function, and quality of life with duloxetine.

Viscosupplementation: Surgery is Not Your Only Option

Viscosupplementation is the introduction of hyaluronic acid, a gel-like fluid, into the joint capsule. This helps reduce friction between bones and, thus, relieves pain and limits joint degeneration.

A systematic review of 25 clinical trials shows viscosupplementation is a safe and effective treatment for osteoarthritis. Another large study, including 4,866 patients with osteoarthritis, corroborates this. Thus, in view of the overwhelming evidence, the EULAR (European Alliance of Associations for Rheumatology) recommends viscosupplementation for all patients with osteoarthritis who do not benefit from medical therapy.

Surgery for Osteoarthritis: The Last Resort

Research shows that ⅓ of all patients with osteoarthritis who undergo surgery do not need it. This is concerning due to the surgery-associated risks:

• Anesthesia-related complications can be fatal in 11% of patients.
• Post-op infections and complications affect up to 53.6% of patients undergoing knee surgery.

Thus, most patients benefit from a trial of viscosupplementation before surgery. This is why doctors recommend surgery only for patients:

• With irreversible joint damage.
• Who do not respond to six months of non-pharmacological and medical treatment (including viscosupplementation).