Special Focus: Osteoarthritis
From the September ACP Observer, copyright © 2007 by the American College of Physicians.
While it may be easier for time-crunched primary care physicians to write a prescription for a patient suffering from osteoarthritis (OA), internists can make a real difference in the life of this patient by focusing on what can be modified in the long term—weight, muscle strength and altered alignment.
Color-enhanced frontal X-ray of a knee showing advanced osteoarthritis. The right side of the image shows severe narrowing of the joint space of the knee, sclerosis and osteophyte formation along the margins of the distal femur and proximal tibia.
"Primary care physicians should recognize risk factors rather than just treating [with medications]," said David Hunter, chief, division of research at New England Baptist Hospital, Boston, and an editorial consultant for the PIER module on OA.
It's not easy to make that time commitment, he acknowledged. But the increasing number of patients with OA will pressure internists to take another look at how to make it happen. OA now occurs in 13% of people aged 60 and older, and that number may double by 2020. The increase is due to the aging of the U.S. population and the growing prevalence of obesity.
The evidence for treating OA has been around for a while, but has not always been put into practice. In particular, weight reduction is critical, yet takes time as well as buy-in from patients—something that can be elusive.
Having a multidisciplinary approach is one long-term solution, Dr. Hunter said. In that scenario, the primary care physician diagnoses the patient with OA, and then brings in other professionals to work with the patient on weight management, a physical therapist to help with exercise, and other specialists as needed. As a result, treating OA patients, Dr. Hunter said, may require a basic change in how the disease is viewed.
"It's difficult [for the primary care physician] to tackle all that in a five-minute consultation," he said. "It is more complicated than the current health care system acknowledges."
Weight control is the most critical, yet most challenging, issue in preventing OA. It requires not only counseling overweight patients with radiographic findings of OA to lose weight to prevent progression, but also requires patient buy-in. Given that each one-pound increase in weight increases the force across the knee joint by two to three pounds, weight loss can have a dramatic effect on OA.
The Framingham study, for example, found that a BMI decrease of more than two units over 10 years reduced the chance of women developing knee OA by 50%. A similar weight gain was associated with an increased risk. If obese men (BMI>30) lost enough weight to fall into the overweight category (BMI 26-29.9) and overweight men lost enough weight to move into the normal category (BMI<26), the incidence of knee OA would decrease by 21.5%. Similar changes in weight in women would result in a 33% decrease in knee OA.
Other studies have shown that obesity is associated with development of both unilateral and bilateral hip OA. Therefore, counsel patients to maintain a BMI below 25.
It may also help to recommend reducing or eliminating activities that combine repetitive knee bending and heavy lifting, which may lead to OA. Certain occupations that require heavy lifting and repetitive knee bending have been shown to increase risk for radiographic knee OA. In fact, these occupations may be responsible for 15% to 30% of knee OA in men.
Quadriceps weakness decreases the ability of muscles to distribute load across the knee joint and maintain joint stability. This weakness may result from OA pain, although the weakness may precede the onset of and be a risk factor for knee RA. Encourage women to maintain quadriceps muscle strength, which increases the muscle's ability to distribute load across the joint and maintains joint stability.
Use appropriate methods to prevent joint injuries. In particular, advise patients who participate in sports to use graduated training schedules and conditioning programs, which have been shown to lead to fewer injuries. They should avoid intense loading of previously injured joints, since that predisposes those joints to OA. For example, while running itself does not increase the risk for knee OA, running on an injured knee may do so. One study showed that young adults who suffered knee injuries were at significantly higher risk for knee OA in later life.
SCREENING AND DIAGNOSIS
Although radiographic OA exists in at least one joint in nearly everyone over age 75, it is mostly asymptomatic. Because current treatment is directed toward symptomatic OA, there is no evidence that shows that screening persons for OA helps prevent the disease or improve outcomes.
OA presents as pain that is:
- deep, aching and not well localized,
- insidious in onset, and
- more noticeable with use early in disease and at rest in advanced disease.
Stiffness after inactivity lasts less than 30 minutes, and there may be crepitus, reduced joint motion and giving way of weight-bearing joints.
Other typical signs include:
- tenderness, usually over the joint line
- bony enlargement of the joint or deformity
- pain on passive range of motion
- instability of the joint
History and physical exam are the keys to making a clinical diagnosis of OA. Radiographs are less sensitive and specific than physical exam (more so for disease of the hip or knee and less so for the hand) and should only be used to confirm clinical suspicion when necessary or to exclude other conditions. Look for osteophytes, joint space narrowing, subchondral sclerosis and cysts. However, these findings don't exclude other diagnoses in patients with joint pain. Localized soft tissue disorders of the knee, hip and hand may cause pain that can be mistaken for OA, and such disorders and OA may coexist. Patients may have trochanteric bursitis, anserine bursitis or de Quervain's tenosynovitis even if they have OA on x-ray.
Magnetic resonance imaging (MRI) can facilitate diagnosis of other causes of joint pain that can mimic OA. However, note that MRIs of the knee frequently detect asymptomatic meniscus tears, which are nearly universal in persons with knee OA but may not be the cause of the patient’s pain.
Do not rely on laboratory testing to establish the diagnosis of OA. Because OA is considered to be a noninflammatory arthropathy, laboratory testing is expected to be normal. However, given the prevalence of OA, especially in elderly patients, it is likely that laboratory abnormalities such as elevated ESR levels and anemia will be present for other reasons. Such findings do not exclude a diagnosis of OA. Instead, use tests to detect conditions that therapy could worsen with treatment. Consider obtaining a blood count, creatinine level, and liver function tests before starting NSAIDs. However, reserve more extensive laboratory testing to exclude other types of arthritis when the diagnosis is uncertain.
Consider using the criteria of the American College of Rheumatology (published Arthritis Rheum 1986;29:1039-49) to diagnose and classify OA of the hip, knee and hands in patients with pain in those joints.
Diagnostic criteria for osteoarthritis
When making the diagnosis of OA consider using the criteria of the American College of Rheumatology for diagnostic purposes and classification of OA of the hip, knee, and hands in patients with pain in these joints.
Hip pain and at least two of the following
- ESR <20 mm/h
- Radiographic femoral or acetabular osteophytes
- Radiographic joint space narrowing (superior, axial, medial)
While previous injury may support an OA diagnosis in symptomatic persons, ACR criteria that can classify knee OA are included in the chart, Criteria for classification of knee osteoarthritis.
Hand pain, aching, or stiffness and hard tissue enlargement of 2 of 10 selected joints (second and third DIP, second and third PIP, and the first carpometacarpal joints of both hands) and
- Fewer than 3 swollen MCP joints and
- Either hard tissue enlargement of 2 or more DIP joints or
- Deformity of 2 or more of 10 selected joints
CONSULTATION FOR DIAGNOSIS AND MANAGEMENT
While primary care physicians can diagnose most cases of OA, consider referral for a consultation if the patient's pattern of joint involvement is atypical or if the patient has symptoms that indicate inflammatory arthritis (e.g., prolonged morning stiffness, soft tissue swelling).
Referrals to a rheumatologist can also help when patients have not responded to standard therapy, when they may have a different or concurrent rheumatologic disease, or if they may require arthrocentesis. Moreover, rheumatologists were more likely than primary care physicians to recommend quadriceps strengthening and other non-drug therapies, according to one study.
Physical and occupational therapists can help with exercise programs as well as determining the need for orthotics and other devices while diet and nutrition experts can help counsel obese patients with lower limb OA. As a last resort, refer patients to orthopedic surgeons for joint replacement or another surgical procedure or when medical therapy has failed.
Hospitalize patients with OA only if they need procedures that cannot be done in an outpatient setting such as major joint arthroplasty or, rarely, for pain control.
Weight loss, exercises and assistive devices such as shoes and braces—not drug therapy—should be the focus of the initial management consultation. Patients with OA are less active and less fit regarding musculoskeletal and cardiovascular status and are more likely overweight compared to normal controls.
Encourage patients with OA to begin appropriate exercise regimens that may include a low-impact aerobic program such as walking, biking, and swimming, and quadriceps strengthening exercises for patients with knee OA. Begin with isometric exercises and then move on to resistance exercises. Studies show that exercise programs can reduce knee and hip pain and increase function for both joints.
Other non-drug therapies include:
- canes for patients with persistent ambulatory pain from hip or knee OA. The cane, which reduces loading force on the joint, should be used in the hand opposite the painful joint.
- orthotics may help certain patients by decreasing NSAID use and increasing compliance, according to one study.
- knee braces, which have been shown to realign the knee, and patellar taping of the knee can help manage pain and disability in patients with OA.
Refer patients with knee and hip OA for physical therapy. Patients will benefit from active and passive range of motion exercise, muscle strengthening, joint protection principles and manual therapy. Refer patients with hand OA for occupational therapy, which will help reduce pain and increase strength and hand function through range of motion exercises, joint protection instruction and splinting of the first carpometacarpal joint. Begin programs at a low intensity to avoid aggravating the pain, which in turn may lead the patient to quit.
Consider recommending acupuncture to patients with knee OA since there is growing evidence that this reduces pain when used as complementary therapy. Although increasing numbers of patients with OA may be using glucosamine or glucosamine plus chondroitin, data suggest its effectiveness is only equivalent to placebo.
Refer patients whose hip and knee pain has not responded to standard therapy to an orthopedic surgeon to consider total joint arthroplasty. Studies show arthroplasty can provide significant pain relief and functional improvement in most patients. However, do not recommend arthroscopic lavage and/or debridement or closed tidal lavage for knee OA.
Acetaminophen is the preferred drug therapy for painful hip and knee OA because it is effective, safe—especially relative to NSAIDs—and inexpensive. Use it in doses not exceeding 4,000 mg/d as initial therapy; it can be taken for up to two years in doses up to 2,600 mg/d without adverse GI outcomes.
If OA pain doesn't respond to acetaminophen, start NSAIDs at the lowest dose possible—naproxen at 250 mg twice daily, ibuprofen at 400 mg three to four times daily, diclofenac at 50 mg two to three times daily. Higher doses may be associated with greater toxicity and do not appear to increase pain relief. Do not use NSAIDs in patients with renal insufficiency. Topical NSAIDs may be considered for patients with knee pain due to OA but may not be readily available in the U.S.
Consider selective COX-2 inhibitors such as celecoxib at 200 mg once daily or 100 mg twice daily in patients who require NSAIDs and who are at high risk for peptic ulcer or GI bleeding, such as those with:
- age 65 or older,
- comorbid medical conditions,
- history of peptic ulcer disease or GI bleeding, or
- concomitant use of anticoagulants.
Although COX-2 inhibitors are less likely to cause GI problems, they have been associated with adverse cardiovascular events and thus should be used cautiously in patients with cardiac risk factors. Patients at higher risk for GI bleeding, those with mild preexisting renal disease or at higher risk of NSAID-induced renal insufficiency because of certain conditions such as hypertension or congestive heart failure may benefit from nonacetylated salicylates (salsalate, choline magnesium trisalicylate).
When these drugs are contraindicated or are not enough to relieve pain, narcotic analgesics and tramadol may play a role. Studies show, for example, that controlled or immediate release oxycodone plus an NSAID provided better pain relief than a placebo and that tramadol is comparable to ibuprofen in relieving hip and knee OA pain. Use extreme caution with these drugs in elderly patients who are more susceptible to side effects.
Use intraarticular glucocorticoids for patients with exacerbations of knee pain due to OA who also have effusions. This reduces pain and swelling quickly, but only for a short time—about one week. Do not use intraarticular steroids more than once every four months because repeated use may cause cartilage and joint damage that can make the OA worse.
Intraarticular hyaluronan is another option for patients with knee OA who have not responded to non-drug therapy and simple analgesics and in whom NSAIDs and COX-2 inhibitors are contraindicated, poorly tolerated or not effective. However, its effect is relatively small, and it is unclear which patients may benefit most.
Consider topical capsaicin to treat OA-related pain of the hand and knee as an adjunct to conservative therapy. Apply a concentration of 0.025% of capsaicin three to four times per day for at least three to four weeks.
PATIENT EDUCATION AND FOLLOW-UP
Encourage patients to participate in self-management programs, such as the Arthritis Foundation's (www.arthritis.org) Self-Help Program, provide resources for social support and coping skills and emphasize that strengthening muscles around affected joints will help prevent further damage.
Optimize patient comfort and function over time by assessing response to therapy, daily function and other needs at follow-up. Ask about severity, location and frequency of pain; activities of daily living; range of motion, knee tenderness and swelling; quadriceps strength and adherence to quadriceps exercises and PT/OT exercises. Ask about adherence to weight loss and exercise programs. Review medication use and adverse effects at each visit and adjust the drug regimen as needed.
|For information on osteoarthritis, see the PIER module "Osteoarthritis"|
The information included herein should never be used as a substitute for clinical judgment and does not represent an official position of ACP.
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