Egypt's second faith is Coptic Christianity. Copts are heirs of an ancient Christian rite. Coptic Christianity was the predominant religion in Egypt until the 10th century when a lot of Christians diverted to Islam. Christianity itself was brought in Egypt by St. Mark in the middle of the first century AD.
Other possible causes of swelling behind the knee include abscesses (infections); tumors of the skin, soft tissue, or bones; bleeding; deep venous thrombosis (blood clot in the deep veins of the legs); or deformity of the joint after a fracture of any of the bones of your knee joint.
Swollen Knee. A swollen knee is a common problem caused by accumulation of fluid in or around the knee joint. It is commonly referred to as water on the knee or a knee joint effusion. A swollen knee can come on suddenly or gradually, and may limit the amount you can move your leg making walking very uncomfortable.