foot injury

[BIGNICK]

Over 4 years ago I stepped on a tree root protruding from the ground.I was wearing thin soled shoes and I experienced pain shooting up my leg momentarily.About 2 weeks later I began to get pain in my leg particularly behind knee--it felt really tense.This tenseness is now not so bad,but does feel quite sore at times.I've also experienced sharp stabbing pains in my leg.If I walk very far I also get pain in foot.Since this incident I've seen several consultants but nobody seems able to help.I've also had various scans and x-rays but all to no avail.If I take the weight off my foot for more than about 5 hours,when I stand on the ground again I can feel the joint at base of toe moving back into its correct position.When this happens I seem to get more pain in my leg.I would be grateful for any help!