What are the signs and symptoms of osteoarthritis (OA) of the knees?

Signs and Symptoms of Osteoarthritis of the Knees

The primary signs and symptoms of knee osteoarthritis include joint pain that worsens with activity, morning stiffness lasting less than 30 minutes, limited range of motion, and difficulty with purposeful movement. 1

Clinical Presentation

Pain Characteristics

• Pain is typically mechanical in nature, worsening with activity and improving with rest 2
• Pain may initially present as intermittent episodes but can progress to become nearly constant in advanced stages 2
• Pain during usage is a common feature, though it has limited diagnostic value (high specificity but low sensitivity) 1

Stiffness

• Morning or inactivity stiffness is typically mild and of limited duration (less than 30 minutes) 1
• This contrasts with inflammatory arthritis where morning stiffness is typically more prolonged 1

Functional Limitations

• Difficulty with purposeful movement, particularly weight-bearing activities 1
• Reduced ability to perform daily activities 1
• Functional impairment may be as severe as in rheumatoid arthritis 1
• Decreased mobility and walking distance 1

Physical Examination Findings

• Joint crepitus (crackling or grating sensation during movement) 2
• Limited range of motion 1
• Joint swelling or effusion 3
• Bony enlargement around the joint margins 2
• Muscle weakness, particularly of the quadriceps 1
• Joint instability or malalignment (may develop as disease progresses) 2

Disease Progression

Early Stage

• Intermittent pain with activity 2
• Minimal stiffness after periods of inactivity 1
• Preserved joint function with minor limitations 1

Advanced Stage

• More constant pain, including at rest and during the night 2
• Increased joint stiffness 1
• Progressive loss of joint function 1
• Development of joint deformity 2

Risk Factors and Associations

• Female sex (women represent 78% of diagnosed cases) 1
• Increasing age, especially over 40 years 1
• Obesity (BMI >25) 1
• Prior joint injury or trauma 1
• Occupation or recreation-related joint usage 1
• Family history of osteoarthritis 1
• Presence of osteoarthritis in other joints (particularly hands) 1

Impact on Quality of Life

• Reduced physical activity levels 4
• Increased disability (accounts for 2.4% of all years lived with disability globally) 4
• Reduced ability to work (affects 66% of US patients with OA) 4
• Increased healthcare utilization (older adults with OA visit physicians more frequently) 1

Common Pitfalls in Assessment

• Poor correlation between radiographic findings and symptom severity 2
• Symptoms may be attributed to normal aging rather than recognized as a treatable condition 1
• Failure to distinguish mechanical knee pain of OA from inflammatory or other causes of knee pain 1
• Overlooking the impact of muscle weakness on symptom severity and functional limitations 1

Early recognition of these signs and symptoms is crucial for timely intervention, which may help slow disease progression and improve quality of life for patients with knee osteoarthritis.