Question:

just returned from a long flight, now have pain behind right knee, cannot put foot flat on floor feel like pins & needles in right leg when sitting

Answer:

The most serious and dangerous possible cause for your symptoms, given that your pain began after a long flight, is a blood clot in your leg (deep venous thrombosis or DVT). I urge you to seek medical attention ASAP. Alternative causes include pain “referred to” the back of your knee due to a “pinched nerve” in your lumbar spine (lower back) – which would usually but not always be accompanied by low back pain, or such knee problems as arthritis, a cartilage tear, or a Baker’s cyst. Again, please consult with your physician as soon as possible.

For more information:

Go to the Sports Medicine health topic.