The medial collateral ligament (MCL) on the inner side of the knee is most often torn when there is a force that strikes the outside of the knee. The MCL attempts to resist widening of the joint and tears if the force is too great. When this happens, you face a recovery time of weeks to months, depending on the grade of the MCL tear.
You've tried nearly everything for your worn-out knee. But the remaining possibilities may include some risky options.
A dislocation of the kneecap occurs when the patella comes completely out of its groove on the end of the thigh bone (femur), and comes to rest on the outside of the knee joint. Kneecap dislocations usually occur as a significant injury the first time the injury occurs, but the kneecap may dislocate much more easily thereafter.
A shoulder separation sounds like an odd injury, but in reality, it refers to the stretching or tearing of ligaments where the collarbone (clavicle) meets the shoulder blade (scapula). This intersection is also called the acromioclavicular or AC joint.
Internal impingement is a specific type of shoulder injury that is seen primarily in throwing athletes.