CA,
Both of my kneecaps partially sublux (slip partially out of the groove in the end of the femur) on a regular basis. In addition, apparently because of the alignment of my hips, my knees are very "knocked" and I have chronic patellar tendonitis. I also have shattered articular cartilage on the surface of my femur in my right knee. I had retinacular release surgery on both knees about 15 years apart. In that surgery, the tissues along the upper outside edge of the kneecap are cut so the kneecap is not held as tightly against the other bones and so the kneecap can move more side to side. The cartilage on the underside of my left kneecap is fissured down to the bone, and that on the underside of my right kneecap is shredded a bit. The surgery on my left knee was successful (in that my kneecap no longer "hangs up"), but that on my right knee wasn't. Although some of my knee problems are obviously mechanical, when my arthritis flares up, my right knee and tendonitis flare up, too.

I've gotten the most improvement (in terms of kneecap pain) in the past by building up the strength in my quadraceps muscles. A PT also taught me how to get up out of a chair while protecting my knee (or sore hip or whatever hurts that day). You tuck one foot under the chair (the foot that should take most of your weight), place your hand on that thigh, and push down firmly with your hand as you are pushing your body up and straightening your knee in a fluid movement. It's less stressful on the knee that's doing the work (and also allows you to get up out of a chair in a dignified manner while wearing a dress--bonus!). Crutches would make it much more difficult. Maybe a PT could help you out with ideas? Even if they don't know AS, almost all of those guys know knees.

I'm sending lots of empathy,

LW