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.
Other injuries that can lead to knee swelling include cartilage or meniscus tears, and knee overuse, which may lead to irritation, states Mayo Clinic. Conditions that can give rise to swollen knees include bursitis, osteoarthritis, rheumatoid arthritis, tumors and infections. Cysts, gout and pseudogout may as well cause knees to swell. Risk factors for swollen knees include advanced age and obesity, explains Mayo Clinic.