my rt. leg slipped on my floor mat in my car on Wednesday night and when I got home, I was not able to bear any wt. on my rt. leg and I had rt. knee pain, moderate, could not fully extend my rt. knee to 180 degrees, only 30 to 45 degrees of flexion, only partial wt. bearing as of Thursday am, and back to 100% normal as of Friday am! what was it?