Hello, As the complaint is about the popliteal fossa region any compression over the area due to soft tissue or other ways might lead to swelling of the same below the injury site. We need to check out for thing like - medial collateral ligament injury, bursitis, varicose veins etc. Having a physical examination of the same can provide more insights. As the history do not mention any kind of injury mechanism this cannot be a ligament injury. But the doubt will follow to the bursitis or varicose veins. In both of the conditions, there is a possibility of swelling below the knee region. Allowing the rest for the knee and avoiding any forceful movement s of the knee joint like flexion and extension should avoid the trauma. Also getting it checked will be of good decision. Left ignored will not be a wise decision. Try keeping the leg in hot water and do ankle movements. Post which keeps the leg elevated over the pillow so the swelling comes down. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Jay Indravadan Patel, Physical Therapist or Physiotherapist