You may consult another knee replacement surgeon to evaluate for your device alignment,axis etc. Depending on your initial pathology in and around knee tissues which I believe were adequately taken care of before your initial surgery, sometimes surrounding pathology remains unabated despite several measures and need to be taken care of even at later time after surgery.A second opinion might remove your doubts and also add up to precise information. Trust your arthroscopist/knee surgeon they might be doing their best for you.

Hi, Your knee ( and all synovial joints ) are enclosed in a special covering called CAPSULE which contains SYNOVIAL FLUID). This is how frictionless movement in the knee joint occurs. Due to various reasons inflammation in the knee capsule can cause it to stick to its inner bones and joint surfaces by forming a mesh of fibrous tissue ( ADHESIONS). This cause limitation in range of motion of the knee joint and pain in the early stages. Sometimes just forced exercise breaks these adhesions ( Can be very painful). If not, we are able to remove these adhesions by Arthroscopy. The tricky thing about adhesions is - joints can also react to surgery or physiotherapy by causing adhesion formation and joints form adhesions if you do not move them enough too! Once you have adhesions in a joint there is always a higher probability to adhesion formation again. Hence the repeated stiffness and procedures you have been advised.
The iliotibial band is a 1" thick band or tissue which starts from the outer part of your hip joint and ends just below the outer part of you knee. It acts like a spring helping to bend your knee and hip joint. A tight Iliotibial band will hinder free movement of your knee joint and can cause pain.
Evidently, knee function depends on many factors concerning the joint surfaces, the capsule, the muscles and tendons surrounding the knee (e.g. quadriceps, hamstring, Iliotibial band) and the tissue response of our joints to stress, inflammation etc. LOA is probably a short form of Looking over arthroscopy and MUA means Manipulation Under anesthesia ( freeing the joint by moving it with force)
This sort of situation can occur with anyone and we have yet to find out why some people are predisposed to such post-operative problems. Repeated attempts have to be made to get the joint into motion and complete motions is sometimes still not possible in spite of all our efforts.