I had to go back to see it but yeah definitely not common, looks like it was probably initially an MCL injury and then the second impact the PCL gave way when his knee hyperextended. The ACL prevents the lower leg from shifting forward under the femur and the PCL does the opposite, usually happens with a blow to the front of the knee. It was definitely not a normal mechanism of injury. (This is about the college injury btw)
Nothing will ever be worse than seeing the Kevin Ware injury live on television but this is up there.