Inrteresting reading about those who share the same thing. I was going down a step on November 17th and my right knee gave out and I fell. The tendon tore completely off my knee cap. I was standing with all my weight on my left leg with the ambulance attendents helping me onto the stretcher when the leg knee gave out also completely tearing off the knee cap. The emergency room personnel examined me and wanted to send me home to see an ortho specialist on Monday. I convinced them, there was something more serious and they called in an ortho to look at it. They then admitted me (Saturday night) and operated on both legs Sunday morning.
(I am 75 and very active and have no known health problems. My knees always felt tight and as a child could never squat as a catcher does. Couldn't sit with legs bent for extended periods of time as the knees started to hurt. Went to a ortho dr about 40 years ago and he said the tendons were too short, a type of "birth defect". Didn't offer or suggest any cure or corrective surgery. I asked the surgeon about what I was told 40 years ago and he said ne never heard of such a thing.) Just a little background.
Had both legs in immobilizers for 12 weeks, no weight bearing for 9 weeks and walked with legs straight for 3 more weeks with a walker then to a cane. It's now been almost 19 weeks since surgery, still going to therapy and both legs can be flexed to 140 degrees. Knees are still swelling especially after exercise and therapy. Dr says it will be a year until I'm back to normal and it's super critical that I work-out in a gym on a regular basis.
I can walk a half mile with no problem. I am normally a fast walker, but so far I can't meet my previous pace.