Definitions for the ratings of the strength of recommendation (A-D) and the levels of evidence (Type I-Type V) are provided at the end of the "Major Recommendations" field.
Diagnosis
Osteoarthritis of the Knee
Definition of the Problem
Osteoarthritis of the knee is an increasingly common problem due to a more active society, often leading to prior knee injuries; an increasingly elderly population; and a growing percentage of the population that is overweight. Osteoarthritis of the knee should be suspected when a patient presents with knee pain that has been longstanding, increases with activity, particularly weight bearing and stairs, and improves with rest. Onset of pain and dysfunction is often insidious. Deformity, fixed contracture, crepitance and effusion are common findings. The differential diagnoses include inflammatory arthritis, bursitis or tendonitis, anterior knee pain and internal derangement.
Recommendations
For patients presenting to the first contact physician with knee pain, those with incapacitating instability, deformity or pain should be referred immediately to a musculoskeletal specialist. For the remainder, initial treatment should include activity modification and trial of an analgesic or non-steroidal anti-inflammatory medication (NSAID) ("A" recommendation). Acetaminophen has been shown to be as effective a pain reliever as NSAIDs in patients with osteoarthritis (OA) of the knee ("A" recommendation). Selective cyclooxygenase II (COX-II) inhibitors should only be used in those patients with renal or GI risk factors ("B" recommendation). Patients that respond well to initial treatment should be monitored. Those that use NSAIDs for 6 months should have a complete blood count (CBC), renal and liver function tests and a stool guaiac every 6 months ("D" recommendation). *See Note from NGC at the end of the "Major Recommendations" field.
Patients should be re-assessed within 1 to 4 weeks, based on the severity of the presenting problem. For patients that fail to respond to the initial treatment, or for whom pain returns, radiographs should be obtained ("D" recommendation). A standing anteroposterior (AP) and a lateral view should be taken initially. A tangential view of the patella-femoral joint ("sunrise" view) and a standing posteroanterior (PA) view taken in 40 degrees of flexion can be useful ("B" recommendation). Radiographic feature of OA include: narrowing of the cartilage space, marginal osteophytes, subchondral sclerosis, and beaking of the tibial spines ("B" recommendation). For those patients with radiographic OA, subsequent treatment should include consideration of: changing to a different NSAID ("B" recommendation), patient education ("D" recommendation), physical therapy ("A" recommendation), and possibly durable medical equipment (DME) ("B" recommendation). Patient education includes counseling about weight loss, avoidance of aggravating activities, and support groups such as the Arthritis Foundation ("B" recommendation). Physical therapy should include general conditioning, muscle strengthening, particularly the quadriceps, and range of motion. Durable medical equipment that can reduce pain includes: assistive devices for ambulation such as a cane, appropriate and occasionally modified footwear, and bracing.
Patients should again be reassessed within 1 to 4 weeks. The final treatment intervention involves consideration of aspiration and cortisone injection ("D" recommendation). If the patient has an effusion and the physician is technically proficient at aspiration, the knee joint should be aspirated in a sterile manner, and the fluid sent for appropriate studies. If the synovial fluid does not show signs of hemarthrosis or infection, the knee joint should be injected with corticosteroid. If the physician is not technically proficient at arthrocentesis, or a hemarthrosis or infection is suspected or confirmed, referral to a musculoskeletal specialist is recommended. In patients without an effusion, a cortisone injection may be indicated if there are signs of inflammation such as: synovial thickening, pain that is diffuse or felt at night or rest, or improved with NSAIDs. Localized knee pain that is felt only with weight bearing is less likely to respond to cortisone injection.
Clinical Outcomes
Control of pain and maintenance of activity correlate well with satisfactory quality of life. If the patient is not satisfied with the outcome due to continued pain and limitation of activity, more aggressive intervention may be warranted. Referral to a musculoskeletal specialist is warranted.
Alternative Approaches
Viscosupplementation ("C" recommendation) may have a role in the treatment of knee pain due to osteoarthritis during the initial 12 weeks in the hands of physicians technically proficient in arthrocentesis. The role of 'Chondroprotective' agents such as Glucosamine (GA) and Chondroitin Sulfate (CS) in treatment of osteoarthritis is not yet clear. There is a need for unbiased studies to clarify the issue.
Definitions:
Strength of Recommendation
A. Type I evidence or consistent findings from multiple studies of types II, III, or IV
B. Types II, III, or IV evidence and findings are generally consistent
C. Types II, III, or IV evidence, but findings are inconsistent
D. Little or no systematic empirical evidence
Levels of Evidence
Type I. Meta-analysis of multiple, well-designed controlled studies; or high power randomized, controlled clinical trial.
Type II. Well-designed experimental study; or low-power randomized, controlled clinical trial.
Type III. Well-designed, non-experimental studies such as nonrandomized, controlled single-group, pre-post, cohort, time, or matched case-control series.
Type IV. Well-designed, non-experimental studies, such as comparative and correlational descriptive and case studies.
Type V. Case reports and clinical examples.
Consensus/opinion (as it is used in bibliography of the original guideline): Articles representing expert consensus and not meeting the rigid I-V measurement are noted to represent consensus/opinion.
