ESSENTIALS OF DIAGNOSIS
A degenerative disorder with minimal articular inflammation.
No systemic symptoms.
Pain relieved by rest; morning stiffness brief.
Radiographic findings: narrowed joint space, osteophytes, increased subchondral bone density, bony cysts.
Osteoarthritis, the most common form of joint disease, is chiefly a disease of aging. Ninety percent of all people have radiographic features of osteoarthritis in weight-bearing joints by age 40. Symptomatic disease increases with age. Sex is also a risk factor; osteoarthritis develops in women more frequently than in men.
This arthropathy is characterized by degeneration of cartilage and by hypertrophy of bone at the articular margins. Inflammation is usually minimal. Hereditary and mechanical factors may be involved in the pathogenesis.
Obesity is a risk factor for osteoarthritis of the knee, hand, and probably of the hip. Recreational running does not increase the incidence of osteoarthritis, but participation in competitive contact sports (eg, football) does. Jobs requiring frequent bending and carrying increase the risk of knee osteoarthritis (see Chapter 41).
Degenerative joint disease is divided into two types: (1) primary, which most commonly affects some or all of the following: the DIP and the proximal interphalangeal (PIP) joints of the fingers (eFigure 20–8), the carpometacarpal joint of the thumb (eFigure 20–9), the hip, the knee (eFigure 20–10), the metatarsophalangeal (MTP) joint of the big toe, and the cervical and lumbar spine; and (2) secondary, which may occur in any joint as a sequela to articular injury. The injury may be acute, as in a fracture; or chronic, as from occupational overuse of a joint or metabolic disease (eg, hyperparathyroidism, hemochromatosis, ochronosis) or joint inflammation (eg, rheumatoid arthritis).
Osteoarthritis with joint space narrowing of both the distal interphalangeal joints and the proximal interphalangeal joints of the left hand. (Used, with permission, from Nicole Richman, MD.)
Radiograph of the left thumb shows loss of the joint space between the proximal thumb metacarpal and the trapezium bone. There is also bony sclerosis and bony cysts noted in both bones and faint osteophytes. Both are characteristic of carpometacarpal (CMC) joint arthritis. There is also proximal and radial subluxation of the thumb metacarpal, indicative of CMC joint ligament laxity, caused by the progressive arthritis. (Used, with permission, from Imboden JB et al. Current Diagnosis & Treatment: Rheumatology, 3e. McGraw-Hill, 2013.)
Osteoarthritis with medial compartment narrowing of both knees. (Used, with permission, from Nicole Richman, MD.)
The onset is insidious. Initially, there is ...