Lipoma Removal from Behind Knee - Is It Possible for Nerve Damage to Affect the Ligament?

I had a lipoma removed behind my knee, just above the joint. Now I have numbness below the skin from the wound to the mid-section of the calf and I can no longer extend my leg completely. At 95% I get excruciating pain in the ligament and of course in the wound. It has been three days and I expect the wound to heal somewhat okay, considering the area, but the numbness and the ligament pain concerns me. Thank you.