Osteoarthritis

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

General Considerations

• Degeneration of cartilage and hypertrophy of bone at the articular margins

• Inflammation is usually minimal

PRIMARY

• Most commonly affects some or all of the following

  • Distal interphalangeal (DIP) joints and, less commonly, proximal interphalangeal (PIP) joints

  • Carpometacarpal joints of the thumbs

  • Hip

  • Knee

  • Metatarsophalangeal joint of the big toe

  • Cervical and lumbar spine

SECONDARY

• May occur in any joint as a sequela to articular injury

• Causes of articular injury that lead to secondary degenerative arthritis include

  • Trauma

  • Gout

  • Rheumatoid arthritis

  • Hyperparathyroidism

  • Hemochromatosis

  • Charcot joint

Demographics

• The most common form of joint disease

• 90% of all people have radiographic features of osteoarthritis in weight-bearing joints by age 40

• Patient sex is also a risk factor; osteoarthritis develops in women more frequently than in men

• Obesity is a risk factor for knee and hand (and probably hip) osteoarthritis

Symptoms and Signs

• Insidious onset

• Pain is made worse by activity or weight bearing and relieved by rest

• Bony enlargement of the interphalangeal joints is occasionally prominent

  • DIP (Heberden nodes)

  • PIP (Bouchard nodes)

• Crepitus may often be felt over the knee

• Joint effusion and other articular signs of inflammation are mild

• Because articular inflammation is minimal and systemic manifestations are absent, degenerative joint disease should seldom be confused with other arthritides

• The distribution of joint involvement in the hands also helps distinguish osteoarthritis from rheumatoid arthritis

  • Osteoarthritis primarily affects the DIP and PIP joints and spares the wrist and metacarpophalangeal joints (except at the thumb)

  • Rheumatoid arthritis involves the wrists and metacarpophalangeal joints and spares the DIP joints

• In some cases, a one-way valve effect between the knee joint and gastrocnemius-semimembranosus bursa can lead to accumulation of synovial fluid, referred to as a popliteal or Baker cyst

• No systemic manifestations

Differential Diagnosis

• Rheumatoid arthritis

• Seronegative spondyloarthropathy, eg, psoriatic arthritis

• Gout

• Chondrocalcinosis, eg, pseudogout, Wilson disease

• Other bone disease, eg, osteoporosis, metastatic cancer, plasma cell myeloma

Laboratory Tests

• No laboratory evidence of inflammation such as elevated erythrocyte sedimentation rate

• Synovial fluid is noninflammatory (Table 20–2)

Imaging Studies

• Radiographs may reveal

  • Narrowing of the joint space

  • Osteophyte formation and lipping of marginal bone

  • Thickened, dense subchondral bone

  • Bone cysts

• The correlation between radiographic findings and symptoms is poor

Diagnostic Procedures

• Aspiration of effusions for pain relief

• Corticosteroid injections for pain relief

Medications

• Nonsteroidal anti-inflammatory drugs (NSAIDs) (see Table 5–5)

  • An option for patients who do not respond to acetaminophen

  • Topical NSAIDs are preferred for patients 75 years of age and older

• Diclofenac gel 1%

  • Recommended dose is 4 g applied to the affected joint four times daily

  • Topical diclofenac appears more effective than placebo for knee and hand osteoarthritis

  • Rates of systemic side effects are lower with topical than with oral diclofenac

• Topical capsaicin may be beneficial for osteoarthritis of the hand but is not recommended for osteoarthritis of the knee or hip

• Acetaminophen is not recommended given that its impact on pain is frequently negligible and hepatotoxicity can occur from high doses

• Duloxetine

  • Can reduce pain

  • Used in patients with osteoarthritis in multiple joints who either have not responded to or cannot use NSAIDs

  • Dosage: 30–60 mg orally daily

  • Nausea occurs in 6–15% of patients

• Chondroitin sulfate and glucosamine, alone or in combination, are no better than placebo in reducing pain in patients with knee or hip osteoarthritis

Surgery

• Total hip and knee replacement provides excellent symptomatic and functional improvement when osteoarthritis severely restricts walking or causes pain at rest, particularly at night

• Arthroscopic surgery is ineffective for knee osteoarthritis

Therapeutic Procedures

• Patients with osteoarthritis of the hand may benefit from assistive devices and instruction on techniques for joint protection

• Splinting is beneficial for those with symptomatic osteoarthritis of the first carpometacarpal joint

• Patients with mild to moderate osteoarthritis of the knee or hip should participate in a regular exercise program (eg, a supervised walking program, hydrotherapy classes) and, if overweight, should lose weight

• Intra-articular injections of corticosteroids, hyaluronate, or platelet-rich plasma

  • Used in patients with moderately severe osteoarthritis of the knee who do not respond to NSAIDs

  • Although each of these can temporarily reduce pain, none has convincingly produced long-term benefits in reducing pain or preserving function

  • The American College of Rheumatology does not recommend corticosteroid injections for osteoarthritis of the hand

Prognosis

• Symptoms may be quite severe and limit activity considerably (especially with involvement of the hips, knees, and cervical spine)

Prevention

• Weight reduction in women reduces the risk of developing symptomatic knee and hand osteoarthritis

• Correcting leg length discrepancy of > 1 cm with shoe modification may prevent knee osteoarthritis from developing in the shorter leg

When to Refer

• When recalcitrant symptoms or functional impairment warrant consideration of joint replacement surgery of the hip or knee