1. Trauma – pointers to the diagnosis are: (a) the history, (b) the presence of a fracture, and (c) a joint effusion, especially a lipohaemarthrosis.

2. Osteoarthritis.

3. Crystal-induced arthritis

4. Rheumatoid arthritis* – occasionally. Also juvenile idiopathic arthritis.

5. Pyogenic arthritis – commonest joints affected are the hip, knee and small joints of the hands and feet. 15% of those due to Staphylococcus aureus and 80% of those of gonococcal aetiology involve two or more joints. The joint may be radiographically normal at first presentation.

6. Tuberculous arthritis – insidious onset with radiological changes present at the time of first examination. Erosions first develop at peripheral non-contact points of the joint.

7. Pigmented villonodular synovitis* – most commonly at the knee.

8. Sympathetic – a joint effusion can occur as a response to a tumour in the adjacent bone.

9. Neuropathic arthropathy*.

10. Synovial chondromatosis.

11. Amyloidosis.

Further Reading

1. Rheumatoid arthritis*.

2. Juvenile idiopathic arthritis.

3. Systemic lupus erythematosus*.

4. Pyogenic arthritis.

5. Tuberculous arthritis.

6. Reiter’s syndrome* – in the acute phase.

7. Scleroderma*.

8. Haemophilia*.

1. Osteoarthritis.

2. Calcium pyrophosphate arthropathy – see Calcium pyrophosphate dihydrate deposition disease*.

3. Gout*.

4. Psoriatic arthropathy*.

5. Ankylosing spondylitis.

6. Reiter’s syndrome* – in chronic or recurrent disease.

7. Neuropathic arthropathy* – especially in the spine and extremities.

8. Pigmented villonodular synovitis*.

1. Juvenile idiopathic arthritis*.

2. Reiter’s syndrome*.

3. Pyogenic arthritis.

4. Psoriatic arthropathy*.

5. Rheumatoid arthritis* – in less than 5% of patients.

6. Hypertrophic osteoarthropathy.

7. Haemophilia*.

8. AIDS-associated arthritis.

1. Early infective or inflammatory arthritis – because of joint effusion.

2. Psoriatic arthropathy* – due to deposition of fibrous tissue.

3. Acromegaly* – due to cartilage overgrowth.

4. Gout*.

5. Pigmented villonodular synovitis.

1. Gout*.

2. Rheumatoid arthritis*.

3. Pigmented villonodular synovitis*.

4. Multicentric reticulohistiocytosis.

5. Amyloidosis.

6. Sarcoidosis*.

Further Reading