Diagnosis
- Clinical diagnosis based on history & physical exam, with laboratory & radiologic investigations requested to exclude other diagnosis
Physical Examination
- Normal exam does not rule out establishing the diagnosis of osteoarthritis
- Features that suggest diagnosis of establishing the diagnosis of osteoarthritis include:
- Tenderness usually over the joint
- Crepitus on joint movement
- Limited range of motion
- Bony enlargement of the finger joints (eg Heberden’s or Bouchard’s nodes)
- Pain on passive range of motion
- Deformity (eg angulation in the hand joints, varus, valgus)
- Joint instability
- Periarticular muscle weakness (ie quadriceps muscle)
Assessment
Diagnostic Criteria of Osteoarthritis by the American College of Rheumatology
Osteoarthritis of the Hand
- Hand pain, aching or stiffness for most days or prior month plus at least 3 of the following features:
- Hard tissue enlargement on ≥2 of selected joints [bilateral 2nd or 3rd distal interphalangeal (DIP), 2nd & 3rd proximal interphalangeal (PIP) or 1st carpometacarpal joints]
- Hard tissue enlargement of ≥2 DIP joints
- <3 swollen metacarpophalangeal joints
- Deformity of at least 1 of selected joints (bilateral 2nd or 3rd DIP, 2nd & 3rd PIP or 1st carpometacarpal joints)
- With sensitivity of 94% & specificity of 87%
Osteoarthritis of the Hip
- Hip pain for most days or prior month plus at least 2 of the following features:
- ESR <20 mm/hr
- Presence of femoral & acetabular osteophytes on X-ray
- Presence of superior, axial, &/or medial joint space narrowing on X-ray
- With sensitivity of 89% & specificity of 91%
Osteoarthritis of the Knee (Clinical & Radiographic Features)
- Knee pain plus 1 of the following features:
- Patient >50 years old
- Stiffness <30 minutes
- Crepitus
- Presence of osteophytes on X-ray
- With sensitivity of 91% & specificity of 86%
Laboratory Tests
- May help exclude other diagnosis & monitor side effects of medications
- Not reliable & required in establishing the diagnosis of osteoarthritis
- May help exclude other diagnosis & monitor medications
- Usually normal, except for possible elevated erythrocyte sedimentation rate (ESR) & anemia, which are common in the elderly
- Should consider obtaining complete blood count (CBC), liver function test (LFT), creatinine (Cr) level before starting therapy with NSAIDs, esp in elderly & in patients with other chronic illness
- Aspiration of synovial fluid may be done to exclude other diagnosis such as septic arthritis, gout, pseudogout
- Usually clear, viscous & with leukocyte count <2000/mm3
Imaging
Imaging Procedures
- Assist in diagnosing establishing the diagnosis of osteoarthritis
- Suggested for patients ≥45 years, with joint pain especially at movement, & with morning stiffness lasting for >30 minutes
Plain X-rays
- Primary imaging method used to confirm the diagnosis of establishing the diagnosis of osteoarthritis, stage its severity & follow its progression
- Severity of radiographic findings do not correlate well with the severity of the symptoms or the presence of functional disability
- Absence of radiologic features does not exclude establishing the diagnosis of osteoarthritis
- May be used to exclude other diagnosis (eg trauma)
- Almost always sufficient in diagnosing establishing the diagnosis of osteoarthritis
- Radiologic features indicative of establishing the diagnosis of osteoarthritis but may not be observed in early disease include the following:
- Joint space narrowing which is often irregular or asymmetric
- Subchondral sclerosis which appears as an increased density in subchondral bone
- Bony proliferation with the presence of osteophytes/spurs
- Cysts in subchondral marrow adjacent to or sometimes remote from the joint which is usually seen in late cases
- Soft tissue changes (eg small effusions, calcification & soft tissue swelling)
- Taken in standing antero-posterior (AP) & lateral position; Should be interpreted together with the clinical presentation of the patient
Magnetic Resonance Imaging (MRI)
- Used to study joints, cartilage, subchondral bone & synovial tissue simultaneously
- May be useful in studying the secondary causes of establishing the diagnosis of osteoarthritis (ie meniscal tear, previous ligament injury) or identifying any intraarticular loose body
Ultrasound
- May be useful in investigating alterations in joint structure & in guiding intra-articular steroid injections but should not be used routinely