Synovitis Diagnosis

Synovitis refers to inflammation of the synovial membrane of the joint, commonly seen in the knee, hip, shoulder, and elbow joints. It manifests as joint swelling, pain, and restricted mobility. Accurate diagnosis of synovitis is crucial for identifying the cause, selecting treatment strategies, and preventing complications.

1. Clinical Symptom Analysis

① Pain

● Mild to moderate persistent pain, aggravated during activity and relieved by rest.

● Obvious pain when the joint is pressed or twisted, indicating severe inflammation.

② Joint Swelling

● Synovitis leads to synovial thickening and increased synovial fluid secretion, resulting in joint swelling.

● Early swelling is mild, but can become more pronounced as the disease progresses.

③ Restricted Movement

● Due to inflammation and swelling, joint flexibility decreases, and some patients experience stiffness.

● In severe cases, flexion and extension may be completely restricted, affecting daily activities.

④ Other Symptoms

● Joint Effusion: A fluid wave sensation can be felt on palpation.

● Morning Stiffness: Patients with rheumatoid synovitis may have prolonged morning stiffness.

● Joint Crepitus: Patients with synovial thickening or cartilage damage may experience abnormal friction sensations.

2. Physical Examination

Doctors evaluate the patient’s joint condition through inspection, palpation, and functional tests.

① Examination of Joint Swelling and Effusion: Floating patella test or fluctuation test is used to assess knee joint effusion.

② Tenderness Examination: Pressing specific joint areas to determine inflammation.

③ Passive and Active Motion Test: Assessing joint range of motion and severity of synovitis.

④ Joint Crepitus Examination: Checking for cartilage damage accompanied by synovitis.

3. Laboratory Tests

① Blood Tests

● C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR): Elevated levels indicate inflammation or infection.

● Rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibodies (Anti-CCP): Used for diagnosing rheumatoid arthritis-related synovitis.

● White blood cell count (WBC): Elevated WBC may indicate infectious synovitis.

② Synovial Fluid Analysis

Synovial fluid is obtained by joint aspiration and analyzed as follows:

● White blood cell count: High levels suggest infection or inflammation.

● Transparency and viscosity of synovial fluid: Cloudy fluid with reduced viscosity indicates infection.

● Bacterial culture: To identify septic synovitis (bacterial infection).

● Uric acid crystal detection: Used to confirm gouty synovitis.

4. Imaging Studies

① X-ray Examination

● Mainly used to rule out fractures, deformities, or osteophytes.

● Early-stage synovitis may appear normal on X-rays, while late-stage may show narrowed joint space or bone destruction.

② Ultrasound Examination

● Can detect synovial thickening, effusion, and degree of inflammation.

● Provides guidance during joint aspiration to improve accuracy.

③ Magnetic Resonance Imaging (MRI)

● The most sensitive imaging method for synovitis, clearly showing synovial thickening, joint effusion, and soft tissue damage.

● Helps differentiate between infectious synovitis, rheumatoid arthritis, and traumatic synovitis.

④ CT Scan

Primarily used for evaluating complex joint injuries or tumor-related synovitis.

5. Synovial Biopsy (Special Cases)

When routine examinations cannot determine the cause, doctors may recommend synovial biopsy in the following cases:

① Suspected Tuberculous Synovitis: Pathological examination may reveal Mycobacterium tuberculosis.

② Suspected Synovial Proliferative Disease: Such as pigmented villonodular synovitis (PVNS).

Conclusion

The diagnosis of synovitis relies on clinical symptoms, physical examination, laboratory tests, and imaging studies. Among these, MRI and synovial fluid analysis are the most important diagnostic tools, helping determine the type, cause, and severity of inflammation. Early and accurate diagnosis is essential for selecting appropriate treatment and preventing synovitis from progressing into joint dysfunction or osteoarticular damage. For unexplained cases, synovial biopsy can be performed to further clarify the cause and ensure precise treatment.