Lupus Arthritis – Knee

Author John Udall MD

Definition

Lupus arthritis of the knee joint is a degenerative process which is different in etiology from the degenerative changes seen with osteoarthritis. It is a chronic inflammatory disorder of autoimmune origin which affects primarily women and African Americans.

It is characterized by systemic manifestations including fever, butterfly malar rash, pancytopenia, pericarditis, nephritis, and polyarthritis. One of the things which sets it apart from osteoarthritis is the lack of bone spurs and osteophytes that is so characteristic in osteoarthritis (degenerative joint disease). Lupus arthritis is usually characterized by an acute, red, tender, swollen, and inflamed knee that often accompanies involvement of other joints. Usually this process is not as destructive as that seen in rheumatoid arthritis.

It is an autoimmune disease in which patients typically test positive for antinuclear antibodies (ANA), HLA-DR3, and sometimes rheumatoid factor (RF). It can lead to inflammation of the synovium and eventual deterioration of the cartilage of the knee joint.

Diagnosis is suspected clinically by involvement of other joints and the other manifestations which are listed above and can be confirmed with lab studies.

Imaging includes the use of plain x-rays. MRI is not usually needed. Aspiration of the knee can help distinguish an inflamed knee secondary to lupus from septic arthritis.

Treatment options depend on the chronicity of the disease and the status of the cartilage. Treatment for lupus arthritis usually includes similar medications used to treat rheumatoid arthritis, and total joint replacement only becomes necessary with severe damage of the cartilage of the joint.

References

Miller, Mark. Review of Orthopaedics, 5th ed. pp 49-50. Saunders Elsevier. Philadelphia. 2008.