Localized deposition of amyloid in articular cartilage.

The frequency, nature and tissue distribution of localized amyloid deposits in articular cartilage of young and elderly patients, with and without evidence of arthritic disease, was determined. Localized amyloid deposits in articular cartilage were not found in young patients with osteoarthritis of the hip or chondromalacia/osteoarthritis of the patella. However, in elderly patients with osteoarthritis of the hip, amyloid deposits were commonly found, although at no greater frequency than in elderly patients with no evidence of arthritis. Amyloid deposits were commonly present (in 95% of cases) in osteoarthritis of the knee joint and in the articular cartilage of all joints containing pyrophosphate deposits. Similar deposits of amyloid were also found in the articular cartilage of 40-45% of rheumatoid joints. These findings indicate that localized amyloid deposits in the articular cartilage are largely age-related and not due to specific pathological alterations affecting articular cartilage.