Claudia698,
Welcome to eHealth. Just a note, if you have a new topic it is best to start a new post. But, anyways.
Oh my goodness, with all those injuries, you are very lucky to be alive. In the days before the trauma systems, you may have passed just waiting for an ambulance to arrive.
You have had significant trauma to all the systems within your body. The injuries you have sustained are similar to those seen in the wounded warriors returning from the war.
This amount of trauma will take a long time to recover from, often as much as 4 or 5 years. You are young and athletic, so you have that on your side. You know how much it takes, both physically and mentally, to achieve what you want in sports and life.
Unfortunately, the body often robs Peter to pay Paul, so to speak. The body will take reserves from the uninjured tissues to heal the damaged ones. So muscles will atrophy and the bones will become osteoporotic. The heart, lungs, and immune systems are stressed to the max. The skin wants to break down and the GI tract just doesn't want to work.
As you have noted, any time you fracture into a joint you will develop traumatic arthritis. Calcaneus fractures are very difficult to treat, and widening is often a problem. This makes shoe wear very difficult and lends to leg length discrepancy. Even though the pubic rami fractures were nondisplaced, patients still occasionally have problems with dyspareunia.
The reason your knee is giving way is due to extreme weakness of the quad muscles. These muscles have been severely damaged by the fractured femur and the following surgeries. So, they have healed with a lot of scar tissue, that is not great in terms of contractile ability. They also have not had to do any work for two years, so the have deconditioned to the max. You have to start from zero and get them back into playing condition.
The mass in your thigh could be from several different things. Two that it could be; is a muscle hernia through the fascia (which would not look any different than muscle on an ultrasound) or the early stage of myositis ossificans (this is where bone actually forms within traumatized muscle. In the early stage, before it calcifies, it may not show up on ultrasound). Other causes of the mass would show up on the ultrasound, like infection, seroma, hematoma, AV malformation, granuloma, foreign body reaction, etc.
One issue that people often do not want to address is that of depression. You have been severely injured in an event that was no fault of your own. You have a long road ahead of you. You are missing out on things that you should be doing at your age. But, it is well known that depression makes pain significantly worse and it can lead to problems with the immune system and tissue healing. So, it is very important to address and treat.
So, you still have that long road ahead of you. But, you are young and strong, so you have a good chance of getting back to a happy, productive life. I know that after my fourth knee replacement and thirty-fifth knee surgery, I got out a poem that my Da gave me when I was 16 and read it again and again. It was the poem "If" by Rudyard Kipling. You might want to get a copy.
Wishing you the very best in your future rehab work. Good luck.