A degenerative joint disease, osteoarthritis (OA) is marked by cartilage erosion, osteophyte formation, joint hypertrophy, and subchondral sclerosis. A leading cause of disability in older adults, it affects more than 30% of American older than age 65. It’s more prevalent in women than men. Overall risk rises with age.
About 80% of people with OA of the knee report movement limitations, and 25% have difficulty performing activities of daily living (ADLs), especially those involving ambulation and transfer. Chronic pain from OA contributes to decreased quality of life, increased depression, immobility, falls, isolation, and diminished restorative sleep. This article describes nonpharmacologic and pharmacologic management of knee OA, associated risks, and delineates the nurse’s role in managing older adults with OA-related knee pain.
Diagnosis of knee OA most often comes from a thorough patient history and exam. The most common presenting symptoms in persons older than age 38 are pain most days of the month, along with at least three other symptoms, such as:
- morning stiffness lasting less than 30 minutes
- bony enlargement of the knee joint without warmth, with or without tenderness.
Other manifestations include occasional knee buckling and symptom aggravation during weight-bearing activities that improves with rest. A key finding is absence of systemic symptoms.
A comprehensive nursing assessment is crucial to developing a safe, appropriate, individualized plan of care for older adults with knee OA. As a nurse, you can play a key role in diagnosis by gathering a detailed history, including risk factors and signs and symptoms. Risk factors for knee OA include trauma linked to abnormal loading of the knee joint, certain types of body build or physiques, genetic factors, occupation, and recreational activities.
Obtain the patient’s pain score and determine symptom onset and duration, specific pain location, whether symptoms are unilateral or bilateral, exacerbating and relieving factors, pain characteristics (such as burning or throbbing), loss of function, and impact of symptoms on ADLs.
Then perform a physical examination, staying alert for crepitus with active range of motion, diminished range of motion, mild joint effusions without palpable warmth, bony tenderness, and bony enlargement, such as varus deformity (inward deviation) to the medial knee joint.
If assessment findings suggest OA, expect the physician to order such studies as weight-bearing radiographs and, if ligament injury is suspected, a magnetic resonance imaging scan. If the physician suspects an inflammatory condition, such as inflammatory arthritis, gout, or infection, he or she will order laboratory tests.
Nonpharmacologic and complementary management of knee OA
Exercise is the key nonpharmacologic treatment for OA, regardless of the patient’s age, comorbidities, pain severity, and disability. Encourage patients to stay active and participate in an exercise program tailored to their exercise capacity and physical limitations. Exercise modalities may include water- and land-based activities that improve functional status, gait, and pain management.
In overweight patients, weight management is essential. Teach patients about a healthy diet and the importance of losing weight. Inform them that a 1-lb weight loss can reduce 4 lb of load on the knee and significantly decrease pain.
Other nonpharmacologic interventions include resting the knee joint between exercise sessions, getting adequate restorative sleep, applying thermal heat alternating with ice or cooling therapy, and using assistive devices.
Complementary and alternative treatments
Complementary and alternative treatments include patellar taping, psychosocial interventions, meditation, t’ai chi, acupuncture, and transcutaneous electrical stimulation. Despite their varying efficacy, more than 40% of adults ages 71 and older with OA use these treatments.
A specific supplement of glucosamine and chondroitin has been widely studied; unfortunately, the combination shows little benefit in knee OA. However, research shows both products are relatively safe (except glucosamine in those with shellfish allergy). Due to lack of scientific evidence, the American College of Rheumatology (ACR) doesn’t recommend using these supplements and advises healthcare providers to educate patients about their potential risks and limited benefits.
Pharmacologic management of knee OA
Drugs used to manage knee OA usually include over-the-counter (OTC) analgesics. Opioids may be prescribed for patients who don’t meet pain-management goals.
Acetaminophen is a first-line drug for pharmacologic management. Regimens vary in strength and frequency but shouldn’t exceed 1 g every 4 hours and a maximum daily dose of 4,000 mg. Teach patients about the risk of liver damage with acetaminophen doses above the daily recommendation, and urge them to avoid alcohol ingestion due to additive effects on the liver. Caution them about using OTC agents that contain acetaminophen. If an acetaminophen regimen fails to reduce pain to a satisfactory level, adding OTC oral or topical nonsteroidal anti-inflammatory drugs (NSAIDs) is recommended.
For patients who don’t obtain a satisfactory clinical response, ACR’s evidence-based guidelines recommend oral or topical NSAIDs (or both) as second-line therapy, in conjunction with nonpharmacologic measures. Topical NSAIDs have proven benefits in knee OA because of their efficacy, safety, and ease of use. They limit systemic drug exposure and GI risk by acting locally with diminished systemic absorption. In the United States, two equally effective topical prescription NSAIDs are available for treating OA pain—diclofenac sodium 1% gel and diclofenac sodium 1.5% in 45.5% dimethyl sulfoxide solution (DMSO). Topical capsaicin, an OTC analgesic, is a potentially effective (and relatively cheap) option when combined with nonpharmacologic methods.
Oral NSAIDs provide analgesic, anti-inflammatory, and antipyretic properties. They reduce inflammation by inhibiting the cyclooxygenase (COX) enzyme responsible for prostaglandin biosynthesis, in turn reducing inflammation.
The COX enzyme has two isoenzymes, COX-1 and COX-2. COX-2 inhibition specifically is linked to reduced inflammation. Be aware that COX inhibition has potential adverse events. COX-1 inhibition raises the risk of GI bleeding, while COX-2 inhibition increases the risk of edema, hypertension, and thrombotic events, such as myocardial infarction (MI). (See the box below.)
Nonselective oral NSAIDs
The two main types of oral NSAIDs are selective and nonselective. Nonselective NSAIDs, such as COX inhibitors, inhibit both COX-1 and COX-2 and thus increase the risk of adverse GI events. More than 20 nonselective oral NSAIDs are on the market. They differ slightly in mechanism of action, safety profile, and half-life.
Patients who fail to respond to anti-inflammatory pharmacologic pain management with acetaminophen and NSAIDs may need to transition to opioids. The decision to progress to opioids hinges on patient variables and should be made collaboratively with the patient. Teach patients about opioids’ risks and side effects, such as respiratory depression, sedation, confusion, increased fall risk, and constipation. Starting with a low dosage and frequency and titrating upward slowly may mitigate these side effects.
Many older adults with knee OA have significant preexisting conditions, such as GI disease, chronic kidney disease, cardiovascular disease, diabetes, and obesity. Healthcare providers must consider the patient’s medical history when choosing pain-management therapies, weighing benefits against risks. Factors to consider include the patient’s age, previous history of peptic ulcer or reflux disease, history of MI or other cardiovascular events, and increased risk for renal injury (as in patients with diabetes or uncontrolled hypertension).
For patients ages 75 and older, ACR strongly recommends topical NSAIDs as initial therapy, with the conditional recommendation of tramadol, duloxetine, intra-articular injections, or a combination as subsequent treatments for patients who don’t improve with first-line recommendations.
Such factors as a history of peptic ulcer or GI bleeding, active Helicobacter pylori infection, concurrent use of high-risk drugs (such as anticoagulants, antiplatelets, corticosteroids, or aspirin), and high-dose or long-term NSAID therapy increase the risk of GI adverse events. A selective NSAID (celecoxib) or nonselective NSAID in combination with a proton pump inhibitor (PPI) is recommended in patients with a history of symptomatic or complicated GI ulcers but no history of GI bleeding.
For patients whose knee OA is poorly controlled and who’ve had symptomatic upper GI bleeding within the last year, physicians usually prescribe a selective NSAID in combination with a PPI, or complete avoidance of NSAID therapy. NSAID therapy should be avoided in older adults at high risk for adverse GI effects.
All NSAIDs carry a “black box” warning from the Food and Drug Administration due to the risk of potentially life-threatening cardiovascular events. NSAIDs should be avoided in patients who’ve had a recent cardiovascular event, such as acute MI, percutaneous coronary angioplasty with stent placement, or coronary artery bypass grafting. They also should be avoided in patients with a history of or high risk for heart failure.
Older adults with a history of or a high risk for cardiovascular disease commonly are prescribed a daily aspirin regimen. Studies show that when taken with aspirin, NSAIDs reduce the cardioprotective efficacy of aspirin. Caution patients against taking NSAIDs and aspirin at the same time. Instruct them to space aspirin and NSAID doses at least 2 hours apart.
All patients receiving NSAIDs are at risk for acute kidney injury. Patients diagnosed with stage IV or V chronic renal disease (which generally equates to a glomerular filtration rate of less than 30 mL/minute) should avoid NSAIDs. Be sure to monitor renal function in patients with stage IV or V renal disease, as well as those at high risk for renal complications (such as patients with preexisting renal disease, cirrhosis, or heart failure and those taking drugs that may increase the risk of renal complications). Signs of renal complications include increased blood pressure, edema, heart failure exacerbation, and decreased renal function.
Improving patient outcomes
Failure to treat OA safely and adequately using evidence-based guidelines affects patients’ quality of life and ability to perform ADLs. It also puts patients at risk for drug complications. The first-line approaches of weight loss, physical exercise, and thermal modalities can greatly improve pain control and patient mobility. Patients who don’t obtain pain relief and mobility goals may benefit from pharmacologic management.
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The authors work at the Medical University of South Carolina in Charleston. Catherine O. Durham and Terri Fowler are instructors; Barbara Edlund is a professor in the MSN/DNP program.