Particle Disease

 

 

General Considerations

• AKA particle inclusion disease or giant cell granulomatous response or aggressive granulomatosis
• Occurs from inflammation and osteolysis secondary to the shedding of portions of a prosthesis, more often the polyethylene and/or methylmethacrylate cement in submicron size
• The granulomatous response elicited manifests as osteolysis
• Typically occurs 1-5 years after surgery, now most often in cementless prostheses
• The head may be made out of a cobalt-chromium alloy with a polyethylene cup
• Particles may migrate along the entire course of the prosthesis

Clinical Findings

• Asymptomatic until substantial bone loss
• Then, pain
• Limb shortening
• Limitation of motion

Imaging Findings

• Normal lucency is < 2mm at cement-bone interface
• Lucencies at metal-cement interface or metal-bone interface may be secondary to surgery and should remain unchanged over time
  • They are usually 2 mm or less
• Lucencies greater than 2 mm can indicate loosening or infection or particle disease, or all three
• Particle disease usually produces multifocal lucencies which may not conform to the shape of the prosthesis
• There is usually no associated sclerotic reaction
• In the hip, the lesions occur mostly at the medial border of the tip of the femoral component

Differential Diagnosis

• Mechanical loosening
• Infection

Treatment

• Surgical revision is almost always necessary

Complications

• Dislocation
• Peri-prosthetic fracture