 Femoral neuropathy after anterior cruciate ligament reconstruction with femoral nerve block may be as high as 24 at 6 postoperative weeks when evaluated prospectively and systematically through a clinical neurological and an electroneuromyography ENMG. It is still unclear whether this neuropathy is the result of the surgery, especially the Tourniquet, or the block nerve. The goal of this study is to define the etiology of this postoperative neuropathy. 