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.
Pain in the lower back or spine, or another part of the knee, can travel through nerves and be felt behind the knee. Less Common Causes of Behind-Knee Pain -Popliteus tendonitis is an injury to or inflammation of a small muscle at the back of the knee called the popliteus. -Gastrocnemius tendonitis is an inflammation of a calf muscle tendon that originates at the back of the knee.