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.
An accident or fall with the knee extended is a common cause of pain behind the knee. Occasionally hyperextension from a sports injury (or aggressive activity) can tear the muscle. Chronic overuse. Excessive running such as in a marathon can lead to pain behind the knee. In addition, bad workout techniques can lead to tendinitis in the legs which can cause a lot of pain. Reactive muscle tone. A reactive muscle from surgery or poor leg function can cause pain behind knee problems.