Chapter 27-10: Osteoarthritis (OA)

TEXTBOOK PRESENTATION

OA most commonly presents in older patients as chronic joint pain and stiffness. Pain is usually worse with activity and improves with rest. Knees, hips, and hands are most commonly affected. On examination of the joints, there is bony enlargement without significant effusions. Mild tenderness may be present along the joint lines. There is limited range of motion. Radiographs are diagnostic.

DISEASE HIGHLIGHTS

1. OA is a disease of aging, with peak prevalence in the eighth decade. However, as obesity is a risk factor, it may be seen in much younger people with severe obesity.

2. More common in women than men

3. Although often referred to as “wear and tear” arthritis, the pathophysiology is actually quite complicated.

4. Joint destruction manifests as a loss of cartilage with change to the underlying bone seen as bony sclerosis and osteophyte formation.

5. Joint distribution

   1. OA is most common in the knees, hips, hands, and spine.

   2. Nearly any joint can be affected.

   3. Non–weight-bearing joints other than the hand, such as the elbow, wrist, and shoulder, are less commonly affected by OA. The ankle is also not a common location.

6. Classic symptoms include

   1. Pain with activity

   2. Relief with rest

   3. Periarticular tenderness

   4. Occasional mildly inflammatory flares

   5. Gelling: Joint stiffness brought on by rest and rapidly resolving with activity.

   6. Late in the disease, constant pain with joint deformation and severe disability is common.

7. Physical exam findings

   1. In general, there is bony enlargement, crepitus, and decreased range of motion without signs of inflammation or synovial thickening.

   2. Knee

      1. Crepitus

      2. Tenderness on joint line

      3. Varus or valgus displacement of the lower leg related to asymmetric loss of the articular cartilage.

   3. Hip

      1. Marked decrease first in internal and then external rotation

      2. Groin pain with rotation of the hip

   4. Hand

      1. Tenderness and bony enlargement of the first carpometacarpal joint

      2. Joint involvement in decreasing order of prevalence is DIP, PIP, MCP.

      3. Heberden nodes (prominent osteophytes of the DIP joints)

      4. Bouchard nodes (prominent osteophytes of the PIP joints)

      5. Figure 27-3 shows a hand with some of the classic findings of OA.

   5. Spine

      1. Signs of spinal OA vary depending on location.

      2. Pain and limited range of motion are common.

      3. Radicular symptoms resulting from osteophyte impingement on nerve roots is seen.

      4. Spinal stenosis with associated symptoms (radiculopathy and pseudoclaudication) can result from bony hypertrophy (see Chapter 7-11: Spinal Stenosis).

EVIDENCE-BASED DIAGNOSIS

1. The diagnosis of OA is clinical, based on a compatible history, physical exam, and radiologic findings.

2. Because of the high prevalence of OA, the diagnosis should lead the differential in any patient with suspicious symptoms.

3. Diagnostic criteria have been established.

   1. Hand

      1. Pain, aching, or stiffness

      2. Three of the following

         1. Hard tissue enlargement of at least 2 of the following joints:

            1. Second and third DIP joints

            2. Second and third PIP joints

            3. First MCP ...