A systematic search of the medical literature was performed on
August 20, 2007, using the terms osteoarthritis and arthritis. The
search, limited to human subjects and English language journals, included
the PubMed and Cochrane Collection databases.
Osteoarthritis (OA) is the most common of the rheumatic diseases,
with a prevalence of approximately 200 per 100,000 person-years,
and is responsible for enormous disability and loss of productivity.1–3 The
prevalence and severity of OA is higher in older age groups than
in younger groups, affecting an estimated 46 million Americans.4
The most common risk factors for the development of OA, which
is typically a multifactorial disease, include obesity, previous
occupation, participation in certain sports, history of joint trauma, and
a genetic predisposition to OA. Patients with osteoarthritis are
less likely to have osteoporosis, probably because heavy individuals
have higher bone density because of weight-bearing, but increased
risk of OA as a result of excessive joint loading.3
The typical patient presenting with OA is older than 50 years
of age and has had the presenting symptoms for months to years,
often having treated them with nonprescription medications or dietary
supplements. Pain in the affected joint is a nearly universal complaint,
and hands, knees, or hips are the most commonly affected joints.
Pain is most common with motion, unless the disease is advanced,
in which case pain can be present at rest. Joint stiffness resolves
with motion and recurs with rest.
Late-stage disease is associated with joint deformity (Fig. 35-1).
Joint space narrowing and/or osteophytes may be evident
in X-ray films (Fig. 35-2). Abnormal alignment of joints and joint effusion
can occur in late disease (Fig. 35-3).
Typical appearance of the bony changes associated with
Heberden’s and Bouchard’s nodes.
Plain X-ray films of the knee demonstrating joint space
Physical findings of joint enlargement and genu varum
of the knees.
The diagnosis of OA is made through history, physical examination,
characteristic radiographic findings, and laboratory testing.2,5 The
major diagnostic goals are: (1) to discriminate between primary
and secondary OA and (2) to clarify the joints involved, severity
of joint involvement, and response to prior therapies, providing
a basis for a treatment plan.
Physical examination reveals a patient in mild, moderate, or
severe pain. Crepitus—a crackling or grating sound heard
with joint movement that is caused by irregularity of joint surface—may
be present. Limited range of motion may be accompanied by joint
The American College of Rheumatology has published traditional
diagnostic criteria and also “decision trees” for