ABSTRACT
Introduction: Osteoarthritis is an important cause of disability and dysfunction in the community. The incidence of osteoarthritis is rising with increasing obesity prevalence and longevity. Osteoarthritis is a degenerative joint disease with articular cartilage loss and reactive bone changes. Some cartilage regeneration with cartilage cell proliferation and cartilage matrix production do occur
Aim: To present a case of osteoarthritis with profound chondroid proliferation and discuss the possible reasons for this unusual reaction are discussed
Materials and methods: A 49 year old obese man decreased sensation on the left side corresponding to the L4 to S1 dermatomes after sustaining a low back injury while swimming. Investigations revealed osteoarthritis in his hip joints. He underwent bilateral total hip replacement during a 12 month period
Results: The femoral heads were very irregular with a polypoid appearance due to areas of florid cartilage proliferation with some ossification. The new cartilage had grown over damaged cartilage and bone. Features of usual osteoarthritis with frayed and fragmented cartilage, bone sclerosis and subchondral cyst formation were also seen
Conclusion: Exuberant chondrocyte proliferation and pronounced new cartilage formation, as seen in this case, are rarely observed in surgically removed specimens. This proliferative articular cartilage change in this patient is likely to represent an attempt at repair. The reason for these proliferation changes is unclear but according to the literature an imbalance between the catabolic and anabolic growth factors and cytokines may account for the changes