Diagnosis of Knee Osteoarthritis

Knee osteoarthritis (KOA) is a common chronic joint disease, mainly manifested as degenerative changes of articular cartilage, osteophyte formation, and joint dysfunction. It is more common in middle-aged and elderly people, but in recent years, young individuals have increasingly become a high-risk group due to sports injuries, obesity, and unhealthy lifestyle habits. The diagnosis of KOA mainly relies on clinical symptoms, physical examination, imaging studies, and laboratory tests to clarify the condition and develop a reasonable treatment plan.

Diagnostic Basis

1. Clinical Symptoms

The symptoms of knee osteoarthritis usually develop gradually, being mild in the early stages, but worsening with disease progression, with increased pain and dysfunction.

① Knee pain

● Aggravated by activity and relieved by rest, with obvious pain after prolonged walking, stair climbing, or exercise.

● In advanced cases, pain may also occur during rest or at night, affecting sleep.

● Weather changes (cold, damp) may exacerbate symptoms.

② Joint stiffness and limited mobility

● After getting up in the morning or prolonged inactivity, the knee feels stiff, lasting for several minutes to half an hour.

● In severe cases, stiffness may persist all day, accompanied by limited mobility, such as difficulty squatting, standing, or climbing stairs.

③ Joint swelling and deformity

● Some patients may experience joint swelling due to synovitis or effusion.

● In advanced stages, it may develop into bow-legged (O-shaped) or knock-kneed (X-shaped) deformities, leading to abnormal gait.

2. Physical Examination

Doctors assess knee joint function and pathological changes through physical examination.

① Inspection

Observe whether the knee joint is red, swollen, or asymmetrical, and whether gait abnormalities (such as limping) are present.

② Palpation

● Check for tenderness points (such as around the patella, joint space).

● Assess for joint effusion (positive patellar tap test).

③ Knee function tests

● Range of motion test: Assess whether the knee joint can fully extend or flex.

● Patellar grind test: Determine whether the patellofemoral joint is involved.

3. Imaging Examinations

Imaging studies are an important method for diagnosing KOA and determining the extent of lesions.

① X-ray examination (preferred)

● Narrowed joint space: Indicates cartilage wear.

● Osteophyte formation: Joint margin proliferation, suggesting bone overgrowth.

● Subchondral bone sclerosis or cysts: Indicate long-term joint damage.

② Magnetic resonance imaging (MRI)

Suitable for early KOA, MRI can detect cartilage damage, synovitis, and meniscus injury.

③ Ultrasound examination

Assesses joint effusion and synovitis, useful for disease monitoring.

4. Laboratory Tests

Laboratory tests help exclude other joint diseases, such as rheumatoid arthritis or gout.

① Blood tests

● C-reactive protein (CRP), erythrocyte sedimentation rate (ESR): Inflammatory markers, usually normal or mildly elevated in KOA.

● Rheumatoid factor (RF), anti-CCP antibodies: If positive, suggest rheumatoid arthritis.

● Uric acid levels: Used to rule out gout.

② Synovial fluid analysis (for difficult cases)

Synovial fluid is usually clear or pale yellow, with normal or mildly elevated white blood cell counts.

Conclusion

Experts at United Life International Medical Center state that the diagnosis of knee osteoarthritis relies on clinical symptoms, physical examination, imaging studies, and laboratory tests. Early diagnosis helps to adopt appropriate treatment measures, slow disease progression, and improve quality of life.