My knee makes a clicking sound?

MRI is normal still the back side of my knee locks and the knee cap makes a pop sound...plsss help?

• i had an injury in my right knee,i was in an awkward position and the weight of my body was put on my knee and it made a click sound at the back of the knee,8 months after the injury my knee is the same and it locks at the back of the knee and my knee cap is not smooth,as in when i stretch my leg a few times it locks and then makes a loud pop sound and opens by moving up and then settling down again, i have had 2 mri's on this knee and both say its normal...i cant walk for more than 5 minutes because then the back of my knee starts locking and then pain all on the inner side of the knee starts....WHAT CAN THIS MEAN?doctors are also not sure what is the cause because the ligaments,miniscus and cartilage all seem fine

• Answer:

  Did they do a side view x ray? My husband had a knee replacement and 5 surgery later from day 1 he has been in so much pain, we went to a different doc had all x rays sent to him and right were my husband has pain a fragment of his knee cap that is in two part the 1st doc never told he also has f my husband's knee up 5 surgery later, My husband had a ultrasound done and also found a bakers cyst. SO ALWAYS GET A 2ND OPION.