Figure 2: (A) Joint architecture: Synovial tissue: synthesizes synovial fluid, nourishes and lubricates the articular cartilage, enabling smooth movement of the joints. The synovial tissue has a synovial lining and the sublining. The synovial lining is composed of Macrophages (Type A synovial cells) and specialized fibroblasts (Type B synovial cells). The uptake of excess synovial fluid or breakdown products of cartilage is achieved by the synovial tissue. Articular cartilage is avascular, aneural, and depends mostly on the synovial fluid for its nutrition and maintenance. The main function of chondrocytes (sole population of cartilage) is the production and maintenance of extracellular matrix and balancing catabolic processes in the joint space. Blood induced joint damage is widely thought to happen by direct damage to the chondrocyte metabolism and integrity by components of the blood, while the indirect one is attributable to the inflammatory mediators and enzymes released by the inflamed synovium as a result of the blood in the joint cavity. (B) Radiographs of knee joints from normal individual (Panel 1), haemophilic patients with articular damage (Panel 2) and synovitis (Panel 3).