We found that increased cartilage degradation is associated with synovial inflammation and the formation of osteophytes in CD11b KO mice after meniscectomy, while we could rule out that an underlying pre-existing pathology or bone phenotype exists in sham-operated knees and knees of old CD11b KO mice, which may predispose them to OA. The gene discussed is ITGAM; the disease is inflammatory response.