Five words have been used to describe osteoarthritis (OA)—progressive, degenerative, inflammatory, chronic, and insidious.
OA is progressive because its symptoms slowly but surely get worse over a lifetime, eventually causing disability and a diminished quality of life. It often begins with a single joint (the knee or hip, for example), but for some people it progresses to other joints, such as the spine, hands, and ankles.
OA is a degenerative disease in which cartilage, the tissue that covers the ends of bones and enables smooth movement, begins to wear away. Some of it wears away naturally; some wears away because of overuse or injury. Whatever the cause, once enough cartilage wears away, there is bone-to-bone contact every time an affected joint is moved. The result is pain, swelling, and stiffness.
OA once was thought not to be an inflammatory disease. However, studies show that it does involve inflammation that may underpin its progressively worse symptoms.
According to the Arthritis Foundation, OA is the most common chronic condition involving inflammation of the joints. Once you have it, you’ll have it for the rest of your life (unless the affected joint is replaced). OA is incurable but extremely manageable.
Of all the words used to describe osteoarthritis, insidious may be the most important. OA can be described as insidious because it comes on slowly and does not at first have obvious symptoms. It may begin with just a stiff back when waking, or a sore knee after exercise. The discomfort may persist or temporarily go away. It is perfectly natural for us to brush off symptoms like these as normal aches and pains. But aches and pains may be the first noticeable signs of a progressive, degenerative, inflammatory, and chronic disease. People who ignore these warning signs put themselves at risk of more severe and harder-to-treat problems later on.
What Happens in Osteoarthritis?
In the early stages of OA, microscopic cracks appear in the cartilage. Early changes also occur in the synovial fluid, subchondral bone (the bone beneath the cartilage), the joint capsule, and other soft tissue. Chondrocytes (cells that produce and maintain cartilage) attempt to counteract this process by increasing the production of growth factors that remodel the cartilage. This repair mechanism fails in later stages and the cartilage becomes soft and irregular, especially in load-bearing joints like the spine, hips, knees, and ankles.
Eventually, areas develop where there is complete erosion of cartilage, and the space between the bones becomes so narrow that bone grates against the opposing surface. The stressed bone fights back with a proliferation of 
cells and blood vessels, resulting in thicker bone in the damaged area. Cysts also may develop. The synovial membrane calcifies, and osteophytes (irregular bony spurs) grow at the edges of the bone. Pieces of bone and damaged cartilage may break off and float within the joint.
Osteoarthritis Risk Factors
The main risk factor for OA is age. The disease is rare in people age 30 and younger. Conversely, at least one in three adults age 65 and older have a diagnosis of OA, while many more have early signs on x-ray but are currently without symptoms. The association with advancing age may be linked to the fact that cartilage naturally becomes less effective with age, due to declining protein levels and a diminished blood supply.
Weight is another major risk factor for OA. The greater your weight, the more stress is placed on your load-bearing joints. Being overweight also elevates levels of inflammatory chemicals.
Gender and race also play a role. Knee OA is 1.7 times more common in women, and erosive OA is 12 times more common. Women also are more likely than men to develop OA in their finger joints. OA generally is more common in Native American people than in other groups, but knee OA is most common in African-American women.
Joints are resilient structures, but consistent overuse of a joint raises the risk of OA. Athletes and people who frequently engage in leisure activities that increase the stress on certain joints are more likely to develop OA. The same is true in people with occupations that require repetitive movements and/or heavy lifting.
At least nine additional factors raise the risk of OA. These are:
- Inactivity. Chronic inactivity is associated with being overweight and obese. Both increase the load on joints. Less physical activity causes stiffness, especially in the knees, and stiffness is an early symptom of OA.
- Smoking. People who smoke experience increased inflammation, cartilage loss, and pain.
- Sex hormones. In women, low estrogen levels are associated with an increased risk of OA, as are low testosterone levels in men.
- Genetics. If you have a strong family history of OA, you may have a gene defect that impacts collagen, which is the main structural protein in bones, cartilage, and soft tissue.
- Injury. Any injury to the joint, especially if it results in deformity.
- Anatomy. Structural abnormalities may put unusual loads on joints.
- Other joint disorders. Gout and pseudogout (covered in Chapter 5), congenital dislocation of the hip, and previous RA or infections make joints more susceptible to OA.
- Bone diseases, such as Paget’s disease (abnormal bone metabolism) and avascular necrosis (lack of blood supply to the bone).
- Other conditions. People with type 2 diabetes have an increased risk of OA in the weight-bearing joints and hands. Other health issues that are associated with OA include the blood disorders sickle cell disease and thalassemia, and acromegaly, a rare condition that results from too much growth hormone.
Osteoarthritis Symptoms
OA initially manifests as stiff joints in the morning, and/or aches and pains after strenuous exercise. Over time, these symptoms become more noticeable—the pain intensifies, range of motion in the joint decreases, and swelling occurs. You also may notice crepitus: cracking, clicking, and popping noises in the joint.
Most people with OA have symptoms that do not affect quality of life—for example, in a study of 714 people with OA, only one in 10 had severe OA, compared to four in 10 with moderate OA and five in 10 with mild OA. Among study participants age 65 and older, two in 10 had severe OA, five in 10 had moderate OA, and three in 10 had mild OA. Those unfortunate enough to develop severe OA may find that their ability to function is significantly impaired in some or all areas of life.
Joints Affected by Osteoarthritis
OA is most likely to affect weight-bearing joints, such as the spine, hips, and knees. The shoulders also are vulnerable because their extensive range of motion makes them susceptible to injuries that increase the risk of OA. The disease also can affect the hands, wrists, feet, and ankles, probably because we use these joints constantly.
Shoulders: Crepitus Is Common
OA in the shoulder causes significant difficulty performing everyday tasks such as dressing, brushing your hair, reaching to get things from cabinets, and driving. Crepitus is most likely to accompany shoulder OA.
Hands: Pain, Stiffness, Weakening
Pain and stiffness are early symptoms of hand OA. Instability and deformity occur later, along with a weakening of the grip that makes it increasingly difficult to perform fine motor tasks, such as writing and opening jars. Bumps may develop on the bone ends.
Spine: Nerve Impingement a Risk
The lumbar spine (lower back) and cervical spine (neck) are particularly vulnerable to OA. Pain may occur in the neck and radiate to the shoulders and arms. Pain in the lower back may radiate to the buttocks and legs. Neck movements may become restricted, and the whole back may appear stiff and inflexible.
In severe cases, nerve impingement—pressure on a nerve caused by bone or soft tissue—occurs. This may be of slow onset, causing weakness, radiating pain, and sensory loss in the arm or leg, or it may manifest as a sudden and acute episode of severe pain and loss of function. Sciatica is a common form of nerve impingement in which pain travels along the path of the sciatic nerve, causing one-sided pain in the lower back, hip, buttock, and leg.
Hips: Radiating Pain
Hip OA causes pain that radiates to the buttocks and even the knees. Other symptoms include an unusual gait or limp, difficulty bending, groin pain upon standing, and difficulty with rotational movements, like getting in and out of a car. The hip may feel stiff, and internal rotation (the ability to roll your knee inward) may be limited.
Knees: Prone to Erosion
The knee joint is particularly susceptible to OA because of the load it supports. Joint effusion (excess fluid) and popliteal cysts (also known as Baker’s cysts, these swellings occur behind the knee) add to the problem. Late in the process, the knee may become unstable and deformed to the extent it deviates outward or inward.
Feet and Ankles: Stiffness Impacts Walking
OA pain and stiffness in the ankle and foot make walking more difficult as the disease progresses. The bones in the mid-foot and ankle are particularly prone to OA, especially the joint of the big toe, where a bunion may develop. A bunion is a bony deformity that forms when the joint becomes diseased. Because of friction from footwear, bunions often get inflamed and may cause significant pain. Lateral deviation of the big toe (movement toward the outside of the foot) also can push the other toes out of alignment, causing deformity.
Osteoarthritis
Beyond the Joints
A 2017 study found that people with OA have a 24 percent greater risk of cardiovascular disease than people who don’t have OA. The reason for the link is not clear, but some experts suggest it may be due to the fact that nonsteroidal anti-inflammatory drugs (NSAIDs)—which many people with OA take to ease pain—raise cardiovascular risk. Being overweight or obese also raises cardiovascular risk, and many people with OA fall into these categories due to the fact that they find it painful to burn calories through exercise.
Diagnostic Tests
for Osteoarthritis
There is no definitive test for OA, and it may mimic other forms of arthritis. To diagnose what is causing your symptoms, your doctor will take a medical history, conduct a physical exam, and order various tests. The diagnosis of arthritis is discussed in depth in Chapter 2, but here is a brief review of the testing methods:
- Blood tests. There are currently no blood tests for OA, but tests to rule out other causes of arthritis may be useful. Blood tests likely will assess your erythrocyte sedimentation rate (to determine the presence of inflammation), and check your levels of C-reactive protein and rheumatoid factor.
- Imaging tests. Subtle joint abnormalities may be seen on an x-ray before OA symptoms occur. Signs suggestive of OA include narrowing of the space between the bones in a joint, thickening or thinning of the bone, and the development of osteophytes and bone cysts. Magnetic resonance imaging (MRI) may be ordered to determine the level of soft tissue damage, while ultrasound is helpful in identifying inflammation and can help guide joint aspiration or injection. Computed tomography may be ordered to further assess bony abnormalities seen in other imaging tests.
- Arthrocentesis. Aspiration of the synovial fluid in a joint can be useful in OA because it helps exclude other causes that might benefit from specific treatment—for example, RA, gout, and infection. You may feel some temporary relief after the aspiration, due to a reduction in fluid pressure.
Osteoarthritis Treatment
The goals of OA treatment are to reduce pain and inflammation, and improve joint function. If you have mild-to-moderate OA, your treatment regimen will likely involve a combination of lifestyle changes, pain medication, 
and complementary approaches. In severe OA, joint surgery may be advisable.
Lifestyle: Weight, Physical Activity
If you are overweight or obese, you may find that losing weight relieves your OA symptoms. A 2018 study in Arthritis Care & Research concluded that people with knee OA should be encouraged to lose up to 20 percent of their body weight if they are overweight or obese.
You also should aim to get as much physical activity as possible. In early OA, exercise may help preserve cartilage (see “Exercise Helps Prevent Degradation of Cartilage”). Once OA has progressed, you may not feel like giving painful joints a workout. However, regular exercise can help preserve your range of motion. Choose exercises that do not aggravate your symptoms, such as walking, swimming, or gentle yoga.
If you are not sure of how to exercise without aggravating your symptoms, ask your doctor to refer you to a physical therapist who can work with you to devise an individualized exercise program.
Medications: Start with Acetaminophen
There has been some investigation into whether certain drugs that are used to treat RA also might relieve pain and disease progression in OA, but research is ongoing. In lieu of clarification on this, most people with OA are advised to relieve their pain with acetaminophen (Tylenol). Keep track of how much of the drug you are taking—acetaminophen is an ingredient in many over-the-counter cold and flu medications, and it is all too easy to inadvertently overdose on it.
If acetaminophen does not provide you with sufficient pain relief, discuss with your doctor whether you should add NSAIDs, such as ibuprofen (Advil, Motrin) and naproxen (Aleve, Naprosyn), to your medication regimen.
Keep in mind that oral NSAIDs are associated with serious side effects, including gastrointestinal bleeding and a raised risk of high blood pressure and heart attack. In older adults, they should be used at the lowest effective dose. Topical NSAIDs also are available, and research suggests that these may be less likely to cause side effects.
Check with your doctor about possible drug interactions if you take other medications. The American Society of Health-System Pharmacists website also has information regarding OA medications (see the Resource on page 79).
Injectable medications for OA include hyaluronic acid. Hyaluronic acid is a key component of the fluid that lubricates joints, but it may be lacking in OA-affected joints. In a procedure called viscosupplementation, a manufactured version of hyaluronic acid is injected into the joint space to provide temporary (typically up to six months) lubrication and pain relief in the joint (see “Hyaluronic Acid Injections Reduce Pain and Improve Function”).
The hyaluronic acid used to make viscosupplements may be derived from rooster combs (the fleshy red growth on a rooster’s head), and people with an allergy to poultry and eggs may not be able to receive this formulation. Newer synthetic formulations are available.
Nerve-Based Treatment: Long-Lasting Relief
For people with knee OA who can’t have or don’t want surgery, nerve blocks can provide almost immediate pain relief that may last for several months. The procedure, which can be done in a doctor’s office, involves injecting an anesthetic drug into at least three nerves that provide sensation to the knee joint.
Complementary Alternatives: Increasingly Popular
Many people with OA report that complementary therapies, such as acupuncture, massage, and spinal manipulation, help alleviate OA pain. A 2018 study found that therapeutic massage may relieve the symptoms of knee OA.
You also may wish to try a glucosamine/chondroitin supplement. Glucosamine and chondroitin are normal components of cartilage, and many people report that taking them in supplement form improves their OA symptoms. Research has been promising for decades, but is still not conclusive.
Other drug-free pain relief options include the application of heat or cold packs. A knee brace or hand/finger splints also may help by supporting and immobilizing affected joints.
If you decide to use complementary approaches to treat your symptoms, be sure to notify your physician. Research suggests that many people do not keep their doctor informed about this. However, it is a wise precaution, particularly if you are using herbal remedies that may interact with conventional medications.
See Chapter 10 for detailed information on a range of complementary treatment approaches that may ease OA.
Surgery: Last Resort
Joint surgery or replacement may be your best option if your symptoms are no longer relieved by lifestyle approaches, standard pain-relieving drugs, or complementary approaches. Surgery also may be considered if OA symptoms are affecting your ability to carry out activities of daily living and/or disturbing your sleep.
While surgery may seem like an extreme choice, most people with OA have excellent outcomes. See Chapter 8 for more information.
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