Infectious Arthritis of the Knee - Erler Zimmer 3D anatomy Series MP2119

This dissection model highlighting an Infectious Arthritis of the Knee is part of the exclusive Monash 3D anatomy series, a comprehensive series of human dissections reproduced with ultra-high resolution color 3D printing.

Clinical history

An 82-year-old man had a history of tuberculosis of the left knee in childhood. He developed a painful swollen knee 10 days before admission to the hospital. Examination revealed an inflamed knee, painful on movement, which improved slightly with antibiotic therapy and rest. Radiography showed a disorganized knee joint, and mid-thigh amputation was performed 3 days after admission. Postoperative recovery was satisfactory.

Pathology

The specimen shows the articular surfaces of one femur and one tibia. The articular surfaces were severely eroded. They are brown in color, very irregular, and there are ruffled adhesions and plaques of yellow necrotic material. No normal articular cartilage is present. Irregular bony protrusions of variable size (up to 1 cm in diameter) are present on the femoral condyles. Staphylococcus aureus was cultured from the joint. This is an example of suppurative arthritis in a joint previously damaged by tuberculosis.

Additional Information.

Suppurative arthritis is usually caused by a bacterial infection in the joint. Diagnosis is made by analysis of synovial fluid, including microscopic examination and culture. Suppurative arthritis is also referred to as pyarthrosis and bacterial or septic arthritis. Tuberculous septic arthritis should be considered in patients presenting with acute or chronic monoarthritis who have an abnormal chest radiograph or eosinophilia or a previous history of tuberculosis.

Pulmonary tuberculosis accounts for about 52 percent of tuberculous infections, but musculoskeletal involvement is present in up to 19 percent of cases.1 It is more common in children than in adults, probably because of the greater amount of bone marrow present in immature bone. In adults, TB shows a preponderance at the spine (40%), followed by the hip (25%) and then the knee (8%). While extrapulmonary manifestations of tuberculosis are common, accounting for about 15-20% of cases in immunocompetent patients, the first presentation of the disease as a joint infection is rare[1].

Scientific references

1. Carrol ED, Clarke JE, Cant AJ. Non-pulmonary tuberculosis. Paediatr Respir Rev. 2001;2:113-9.

What advantages does the Monash University anatomical dissection collection offer over plastic models or plastinated human specimens?

• Each body replica has been carefully created from selected patient X-ray data or human cadaver specimens selected by a highly trained team of anatomists at the Monash University Center for Human Anatomy Education to illustrate a range of clinically important areas of anatomy with a quality and fidelity that cannot be achieved with conventional anatomical models-this is real anatomy, not stylized anatomy.
• Each body replica has been rigorously checked by a team of highly trained anatomists at the Center for Human Anatomy Education, Monash University, to ensure the anatomical accuracy of the final product.
• The body replicas are not real human tissue and therefore not subject to any barriers of transportation, import, or use in educational facilities that do not hold an anatomy license. The Monash 3D Anatomy dissection series avoids these and other ethical issues that are raised when dealing with plastinated human remains.