I had an ACD Arthroplasty on C5/6 on Apr 26, 2016. The recovery did not go well, and my symptoms became worse. X-rays showed abnormal angulation and movement of the artificial disc, so I was scheduled to have it removed. I had an ACDF on Aug 26, 2016. The surgeon told me that the disc was defective. The abnormal angulation was because the center piece had became dislodged and was preventing the correct movement and placement of the disc. He also stated that C5/6 were completely unstable because of this. I am so thankful that I had not gotten into a car accident during the period of instability. Just curious if anyone else has experienced this. When I asked the surgeon how many times he has seen this happen, he said never.